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SMU physicists: CERN’s Large Hadron Collider is once again smashing protons, taking data

CERN’s Large Hadron Collider (LHC) and its experiments are back in action, now taking physics data for 2016 to get an improved understanding of fundamental physics.

Following its annual winter break, the most powerful collider in the world has been switched back on.

Geneva-based CERN’s Large Hadron Collider (LHC) — an accelerator complex and its experiments — has been fine-tuned using low-intensity beams and pilot proton collisions, and now the LHC and the experiments are ready to take an abundance of data.

The goal is to improve our understanding of fundamental physics, which ultimately in decades to come can drive innovation and inventions by researchers in other fields.

Scientists from SMU’s Department of Physics are among the several thousand physicists worldwide who contribute on the LHC research.

“All of us here hope that some of the early hints will be confirmed and an unexpected physics phenomenon will show up,” said Ryszard Stroynowski, SMU professor and a principal investigator on the LHC. “If something new does appear, we will try to contribute to the understanding of what it may be.”

SMU physicists work on the LHC’s ATLAS experiment. Run 1 of the Large Hadron Collider made headlines in 2012 when scientists observed in the data a new fundamental particle, the Higgs boson. The collider was then paused for an extensive upgrade and came back much more powerful than before. As part of Run 2, physicists on the Large Hadron Collider’s experiments are analyzing new proton collision data to unravel the structure of the Higgs.

The Higgs was the last piece of the puzzle for the Standard Model — a theory that offers the best description of the known fundamental particles and the forces that govern them. In 2016 the ATLAS and CMS collaborations of the LHC will study this boson in depth.

Over the next three to four months there is a need to verify the measurements of the Higgs properties taken in 2015 at lower energies with less data, Stroynowski said.

“We also must check all hints of possible deviations from the Standard Model seen in the earlier data — whether they were real effects or just statistical fluctuations,” he said. “In the long term, over the next one to two years, we’ll pursue studies of the Higgs decays to heavy b quarks leading to the understanding of how one Higgs particle interacts with other Higgs particles.”

In addition, the connection between the Higgs Boson and the bottom quark is an important relationship that is well-described in the Standard Model but poorly understood by experiments, said Stephen Sekula, SMU associate professor. The SMU ATLAS group will continue work started last year to study the connection, Sekula said.

“We will be focused on measuring this relationship in both Standard Model and Beyond-the-Standard Model contexts,” he said.

SMU physicists also study Higgs-boson interactions with the most massive known particle, the top-quark, said Robert Kehoe, SMU associate professor.

“This interaction is also not well-understood,” Kehoe said. “Our group continues to focus on the first direct measurement of the strength of this interaction, which may reveal whether the Higgs mechanism of the Standard Model is truly fundamental.”

All those measurements are key goals in the ATLAS Run 2 and beyond physics program, Sekula said. In addition, none of the ultimate physics goals can be achieved without faultless operation of the complex ATLAS detector, its software and data acquisition system.

“The SMU group maintains work on operations, improvements and maintenance of two components of ATLAS — the Liquid Argon Calorimeter and data acquisition trigger,” Stroynowski said.

Intensity of the beam to increase, supplying six times more proton collisions
Following a short commissioning period, the LHC operators will now increase the intensity of the beams so that the machine produces a larger number of collisions.

“The LHC is running extremely well,” said CERN Director for Accelerators and Technology, Frédérick Bordry. “We now have an ambitious goal for 2016, as we plan to deliver around six times more data than in 2015.”

The LHC’s collisions produce subatomic fireballs of energy, which morph into the fundamental building blocks of matter. The four particle detectors located on the LHC’s ring allow scientists to record and study the properties of these building blocks and look for new fundamental particles and forces.

This is the second year the LHC will run at a collision energy of 13 TeV. During the first phase of Run 2 in 2015, operators mastered steering the accelerator at this new higher energy by gradually increasing the intensity of the beams.

“The restart of the LHC always brings with it great emotion”, said Fabiola Gianotti, CERN Director General. “With the 2016 data the experiments will be able to perform improved measurements of the Higgs boson and other known particles and phenomena, and look for new physics with an increased discovery potential.”

New exploration can begin at higher energy, with much more data
Beams are made of “trains” of bunches, each containing around 100 billion protons, moving at almost the speed of light around the 27-kilometre ring of the LHC. These bunch trains circulate in opposite directions and cross each other at the center of experiments. Last year, operators increased the number of proton bunches up to 2,244 per beam, spaced at intervals of 25 nanoseconds. These enabled the ATLAS and CMS collaborations to study data from about 400 million million proton–proton collisions. In 2016 operators will increase the number of particles circulating in the machine and the squeezing of the beams in the collision regions. The LHC will generate up to 1 billion collisions per second in the experiments.

“In 2015 we opened the doors to a completely new landscape with unprecedented energy. Now we can begin to explore this landscape in depth,” said CERN Director for Research and Computing Eckhard Elsen.

Between 2010 and 2013 the LHC produced proton-proton collisions with 8 Tera-electronvolts of energy. In the spring of 2015, after a two-year shutdown, LHC operators ramped up the collision energy to 13 TeV. This increase in energy enables scientists to explore a new realm of physics that was previously inaccessible. Run II collisions also produce Higgs bosons — the groundbreaking particle discovered in LHC Run I — 25 percent faster than Run I collisions and increase the chances of finding new massive particles by more than 40 percent.

But there are still several questions that remain unanswered by the Standard Model, such as why nature prefers matter to antimatter, and what dark matter consists of, despite it potentially making up one quarter of our universe.

The huge amounts of data from the 2016 LHC run will enable physicists to challenge these and many other questions, to probe the Standard Model further and to possibly find clues about the physics that lies beyond it.

The physics run with protons will last six months. The machine will then be set up for a four-week run colliding protons with lead ions.

“We’re proud to support more than a thousand U.S. scientists and engineers who play integral parts in operating the detectors, analyzing the data, and developing tools and technologies to upgrade the LHC’s performance in this international endeavor,” said Jim Siegrist, Associate Director of Science for High Energy Physics in the U.S. Department of Energy’s Office of Science. “The LHC is the only place in the world where this kind of research can be performed, and we are a fully committed partner on the LHC experiments and the future development of the collider itself.”

The four largest LHC experimental collaborations, ALICE, ATLAS, CMS and LHCb, now start to collect and analyze the 2016 data. Their broad physics program will be complemented by the measurements of three smaller experiments — TOTEM, LHCf and MoEDAL — which focus with enhanced sensitivity on specific features of proton collisions. — SMU, CERN and Fermilab

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Physicists tune Large Hadron Collider to find “sweet spot” in high-energy proton smasher

New launch of the world’s most powerful particle accelerator is the most stringent test yet of our accepted theories of how subatomic particles work and interact.

Start up of the world’s largest science experiment is underway — with protons traveling in opposite directions at almost the speed of light in the deep underground tunnel called the Large Hadron Collider near Geneva.

As protons collide, physicists will peer into the resulting particle showers for new discoveries about the universe, said Ryszard Stroynowski, a collaborator on one of the collider’s key experiments and a professor in the Department of Physics at Southern Methodist University, Dallas.

“The hoopla and enthusiastic articles generated by discovery of the Higgs boson two years ago left an impression among many people that we have succeeded, we are done, we understand everything,” said Stroynowski, who is the senior member of SMU’s Large Hadron Collider team. “The reality is far from this. The only thing that we have found is that Higgs exist and therefore the Higgs mechanism of generating the mass of fundamental particles is possible.”

There is much more to be learned during Run 2 of the world’s most powerful particle accelerator.

The Large Hadron Collider, the most powerful proton smasher in the world, includes the ATLAS detector, one of the LHC's four particle detectors. (CERN)
The Large Hadron Collider, the most powerful proton smasher in the world, includes the ATLAS detector, one of the LHC’s four particle detectors. (CERN)

“In a way we kicked a can down the road because we still do not have sufficient precision to know where to look for the really, really new physics that is suggested by astronomical observations,” he said. “The observed facts that are not explained by current theory are many.”

The LHC’s control room in Geneva on April 5 restarted the Large Hadron Collider. A project of CERN, the European Organization for Nuclear Research, the 17-mile LHC tunnel — big enough to ride a bicycle through — straddles the border between France and Switzerland.

Two years ago it made headlines worldwide when its global collaboration of thousands of scientists discovered the Higgs Boson fundamental particle.

The Large Hadron Collider’s first run began in 2009. In 2012 it was paused for an extensive upgrade.

The new upgraded and supercharged LHC restarts at almost twice the energy and higher intensity than it was operating at previously, so it will deliver much more data.

The Liquid Argon Calorimeter sits at the heart of the ATLAS detector
Data flowing from the ATLAS detector’s Liquid Argon Calorimeter — which measures the energies carried by particle interactions — is delivered via a data link computer chip developed by physicists at Southern Methodist University. (CERN)

“I think that in the LHC Run 2 we will sieve through more data than in all particle physics experiments in the world together for the past 50 years,” Stroynowski said. “Nature would be really strange if we do not find something new.”

SMU is active on the LHC’s ATLAS detector experiment
Within the big LHC tunnel, gigantic particle detectors at four interaction points along the ring record the proton collisions that are generated when the beams collide.

In routine operation, protons make 11,245 laps of the LHC per second — producing up to 1 billion collisions per second. With that many collisions, each detector captures collision events 40 million times each second.

That’s a lot of collision data, says SMU physicist Robert Kehoe, a member of the ATLAS particle detector experiment with Stroynowski and other SMU physicists.

Evaluating that much data isn’t humanly possible, so a computerized ATLAS hardware “trigger system” grabs the data, makes a fast evaluation, decides if it might hold something of interest to physicists, than quickly discards or saves it.

The Liquid Argon Calorimeter sits at the heart of ATLAS, measuring the energies carried by particle interactions. (CERN)
The Liquid Argon Calorimeter sits at the heart of ATLAS, measuring the energies carried by particle interactions. (CERN)

“That gets rid of 99.999 percent of the data,” Kehoe said. “This trigger hardware system makes measurements — but they are very crude, fast and primitive.”

To further pare down the data, a custom-designed software program culls even more data from each nano-second grab, reducing 40 million events down to 200.

Two groups from SMU, one led by Kehoe, helped develop software to monitor the performance of the trigger systems’ thousands of computer processors.

“The software program has to be accurate in deciding which 200 to keep. We must be very careful that it’s the right 200 — the 200 that might tell us more about the Higgs boson, for example. If it’s not the right 200, then we can’t achieve our scientific goals.”

The ATLAS computers are part of CERN’s computing center, which stores more than 30 petabytes of data from the LHC experiments every year, the equivalent of 1.2 million Blu-ray discs.

Flood of data from ATLAS transmitted via tiny electronics designed at SMU to withstand harsh conditions
An SMU physics team also collaborates on the design, construction and delivery of the ATLAS “readout” system — an electronic system within the ATLAS trigger system that sends collision data from ATLAS to its data processing farm.

Data from the ATLAS particle detector’s Liquid Argon Calorimeter is transmitted via 1,524 small fiber-optic transmitters. A powerful and reliable workhorse, the link is one of thousands of critical components on the LHC that contributed to discovery and precision measurement of the Higgs boson.

The custom-made high-speed data transmitters were designed to withstand extremely harsh conditions — low temperature and high radiation.

“It’s not always a smooth ride operating electronics in such a harsh environment,” said Jingbo Ye, the physics professor who leads the SMU data-link team. “Failure of any transmitter results in the loss of a chunk of valuable data. We’re working to improve the design for future detectors because by 2017 and 2018, the existing optical data-link design won’t be able to carry all the data.”

Each electrical-to-optical and optical-to-electrical signal converter transmits 1.6 gigabytes of data per second. Lighter and smaller than their widely used commercial counterpart, the tiny, wickedly fast transmitters have been transmitting from the Liquid Argon Calorimeter for about 10 years.

Upgraded optical data link is now in the works to accommodate beefed-up data flow
A more powerful data link — much smaller and faster than the current one — is in research and development now. Slated for installation in 2017, it has the capacity to deliver 5.2 gigabytes of data per second.

The new link’s design has been even more challenging than the first, Ye said. It has a smaller footprint than the first, but handles more data, while at the same time maintaining the existing power supply and heat exchanger now in the ATLAS detector.

The link will have the highest data density in the world of any data link based on the transmitter optical subassembly TOSA, a standard industrial package, Ye said.

Fine-tuning the new, upgraded machine will take several weeks
The world’s most powerful machine for smashing protons together will require some “tuning” before physicists from around the world are ready to take data, said Stephen Sekula, a researcher on ATLAS and assistant professor of physics at SMU.

The trick is to get reliable, stable beams that can remain in collision state for 8 to 12 to 24 hours at a time, so that the particle physicists working on the experiments, who prize stability, will be satisfied with the quality of the beam conditions being delivered to them, Sekula said.

“The LHC isn’t a toaster,” he said. “We’re not stamping thousands of them out of a factory every day, there’s only one of them on the planet and when you upgrade it it’s a new piece of equipment with new idiosyncrasies, so there’s no guarantee it will behave as it did before.”

Machine physicists at CERN must learn the nuances of the upgraded machine, he said. The beam must be stable, so physicists on shifts in the control room can take high-quality data under stable operating conditions.

The process will take weeks, Sekula said.

10 times as many Higgs particles means a flood of data to sift for gems
LHC Run 2 will collide particles at a staggering 13 teraelectronvolts (TeV), which is 60 percent higher than any accelerator has achieved before.

“On paper, Run 2 will give us four times more data than we took on Run 1,” Sekula said. “But each of those multiples of data are actually worth more. Because not only are we going to take more collisions, we’re going to do it at a higher energy. When you do more collisions and you do them at a higher energy, the rate at which you make Higgs Bosons goes way up. We’re going to get 10 times more Higgs than we did in run 1 — at least.”

SMU’s ManeFrame supercomputer plays a key role in helping physicists from the Large Hadron Collider experiments. One of the fastest academic supercomputers in the nation, it allows physicists at SMU and around the world to sift through the flood of data, quickly analyze massive amounts of information, and deliver results to the collaborating scientists.

During Run 1, the LHC delivered about 8,500 Higgs particles a week to the scientists, but also delivered a huge number of other kinds of particles that have to be sifted away to find the Higgs particles. Run 2 will make 10 times that, Sekula said. “So they’ll rain from the sky. And with more Higgs, we’ll have an easier time sifting the gems out of the gravel.”

Run 2 will operate at the energy originally intended for Run 1, which was initially stalled by a faulty electrical connection on some superconducting magnets in a sector of the tunnel. Machine physicists were able to get the machine running — just never at full power. And still the Higgs was discovered, notes SMU physics professor Fredrick Olness.

“The 2008 magnet accident at the LHC underscores just how complex a machine this is,” Olness said. “We are pushing the technology to the cutting-edge.”

Huge possibilities for new discoveries, but some will be more important than others
There are a handful of major new discoveries that could emerge from Run 2 data, Stroynowski said.

  • New physics laws related to Higgs — Physicists know only global Higgs properties, many with very poor understanding. They will be measuring Higgs properties with much greater precision, and any deviation from the present picture will indicate new physics laws. “Improved precision is the only guaranteed outcome of the coming run,” Stroynowski said. “But of course we hope that not everything will be as expected. Any deviation may be due to supersymmetry or something completely new.”
  • Why basic particles have such a huge range of masses — Clarity achieved by precision measurements of Higgs properties may help to shed light on the exact reason for the pattern of masses found in the known fundamental particles. If new particles are discovered in the LHC during Run 2, the mathematical theories that could explain them might also shed light on the puzzle of why masses have such diversity in the building blocks of nature
  • Dark matter — Astronomical observations require a new form of matter that acts only via gravity, otherwise all galaxies would have fallen apart a long time ago. One candidate theory is supersymmetry, which predicts a host of new particles. Some of those particles, if they exist, would fit the characteristics of dark matter. LHC scientists will be looking for them in the coming run both directly, and for indirect effects.
  • Quark gluon plasma — In collisions of lead nuclei with each other, LHC scientists have observed a new form of matter called quark gluon plasma. Thought to have been present in the cosmos near the very beginning of time, making and studying this state of matter could teach us more about the early, hot, dense universe.
  • Mini black-holes — Some scientists are looking for “mini black-holes” predicted by innovative physicist Stephen Hawking, but that is considered “a v-e-e-e-e-r-y long shot,” Stroynowski said.
  • Matter-antimatter — A cosmic imbalance in the amounts of matter and its opposite, antimatter, must be explained by particle physics. The LHC is home to several experiments and teams that aim to search for answers.

— SMU, Fermilab, CERN

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SMU physicists celebrate Nobel Prize for discovery of Higgs boson “god particle”

SMU joins nearly 2,000 physicists from U.S. institutions — including 89 U.S. universities and seven U.S. DOE labs — that participate in discovery experiments

SMU’s experimental physics group played a pivotal role in discovering the Higgs boson — the particle that proves the theory for which two scientists have received the 2013 Nobel Prize in Physics.

The Royal Swedish Academy of Sciences today awarded the Nobel Prize to theorists Peter W. Higgs and François Englert to recognize their work developing the theory of what is now known as the Higgs field, which gives elementary particles mass. U.S. scientists played a significant role in advancing the theory and in discovering the particle that proves the existence of the Higgs field, the Higgs boson.

The Nobel citation recognizes Higgs and Englert “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN’s Large Hadron Collider.”

In the 1960s, Higgs and Englert, along with other theorists, including Robert Brout, Tom Kibble and Americans Carl Hagen and Gerald Guralnik, published papers introducing key concepts in the theory of the Higgs field. In 2012, scientists on the international ATLAS and CMS experiments, performed at the Large Hadron Collider at CERN laboratory in Europe, confirmed this theory when they announced the discovery of the Higgs boson.

“A scientist may test out a thousand different ideas over the course of a career. If you’re fortunate, you get to experiment with one that works,” says SMU physicist Ryszard Stroynowski, a principal investigator in the search for the Higgs boson. As the leader of an SMU Department of Physics team working on the experiment, Stroynowski served as U.S. coordinator for the ATLAS Experiment’s Liquid Argon Calorimeter, which measures energy from the particles created by proton collisions.

The University’s experimental physics group has been involved since 1994 and is a major contributor to the research, the heart of which is the Large Hadron Collider particle accelerator on the border with Switzerland and France.

SMU joins nearly 2,000 physicists from U.S. institutions — including 89 U.S. universities and seven U.S. Department of Energy laboratories — that participate in the ATLAS and CMS experiments, making up about 23 percent of the ATLAS collaboration and 33 percent of CMS at the time of the Higgs discovery. Brookhaven National Laboratory serves as the U.S. hub for the ATLAS experiment, and Fermi National Accelerator Laboratory serves as the U.S. hub for the CMS experiment. U.S. scientists provided a significant portion of the intellectual leadership on Higgs analysis teams for both experiments.

Preliminary discovery results were announced July 4, 2012 at CERN, the European Organization for Nuclear Research, near Geneva, Switzerland, and at the International Conference of High Energy Physics in Melbourne, Australia.

“It is an honor that the Nobel Committee recognizes these theorists for their role in predicting what is one of the biggest discoveries in particle physics in the last few decades,” said Fermilab Director Nigel Lockyer. “I congratulate the whole particle physics community for this achievement.”

The majority of U.S. scientists participating in LHC experiments work primarily from their home institutions, remotely accessing and analyzing data through high-capacity networks and grid computing. The United States plays an important role in this distributed computing system, providing 23 percent of the computing power for ATLAS and 40 percent for CMS. The United States also supplied or played a leading role in several main components of the two detectors and the LHC accelerator, amounting to a value of $164 million for the ATLAS detector, $167 million for the CMS detector, and $200 million for the LHC. Support for the U.S. effort comes from the U.S. Department of Energy Office of Science and the National Science Foundation.

“It’s wonderful to see a 50-year-old theory confirmed after decades of hard work and remarkable ingenuity,” said Brookhaven National Laboratory Director Doon Gibbs. “The U.S. has played a key role, contributing scientific and technical expertise along with essential computing and data analysis capabilities — all of which were necessary to bring the Higgs out of hiding. It’s a privilege to share in the success of an experiment that has changed the face of science.”

The discovery of the Higgs boson at CERN was the culmination of decades of effort by physicists and engineers around the world, at the LHC but also at other accelerators such as the Tevatron accelerator, located at Fermilab, and the Large Electron Positron accelerator, which once inhabited the tunnel where the LHC resides. Work by scientists at the Tevatron and LEP developed search techniques and eliminated a significant fraction of the space in which the Higgs boson could hide.

Several contributors from SMU have made their mark on the project at various stages, including current Department of Physics faculty members Ryszard Stroynowski, Jingbo Ye, Robert Kehoe and Stephen Sekula. Faculty members Pavel Nadolsky and Fred Olness performed theoretical calculations used in various aspects of data analysis.

University postdoctoral fellows on the ATLAS Experiment have included Julia Hoffmann, David Joffe, Ana Firan, Haleh Hadavand, Peter Renkel, Aidan Randle-Conde and Daniel Goldin.

SMU has awarded eight Ph.D. and seven M.Sc. degrees to students who performed advanced work on ATLAS, including Ryan Rios, Rozmin Daya, Renat Ishmukhametov, Tingting Cao, Kamile Dindar, Pavel Zarzhitsky and Azzedin Kasmi.

Significant contributions to ATLAS have also been made by SMU faculty members in the Department of Physics’ Optoelectronics Lab, including Tiankuan Liu, Annie Xiang and Datao Gong.

“The discovery of the Higgs is a great achievement, confirming an idea that will require rewriting of the textbooks,” Stroynowski says. “But there is much more to be learned from the LHC and from ATLAS data in the next few years. We look forward to continuing this work.”

Higgs and Englert published their papers independently and did not meet in person until the July 4, 2012, announcement of the discovery of the Higgs boson at CERN. Higgs, 84, is a professor emeritus at the University of Edinburgh in Scotland. Englert, 80, is a professor emeritus at Universite Libre de Bruxelles in Belgium.

The prize was announced at 5:45 a.m. CDT on Tuesday, Oct. 8, 2013.

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Observed! SMU’s LHC physicists confirm new particle; Higgs ‘God particle’ opens new frontier of exploration

Physicists from SMU and around the globe were euphoric Wednesday with the revelation that a new particle consistent with the Higgs boson “God particle” has been observed.

Described as a great triumph for science, the observation is the biggest physics discovery of the last 50 years and opens what scientists said is a vast new frontier for more research.

The achievement is the result of the global CERN scientific collaboration of thousands of scientists, including physicists from SMU, and CERN’s massive $10 billion Large Hadron Collider proton smasher.

“The observation opens up clear directions for physicists at SMU and throughout the world to study the properties of the Higgs,” said SMU physicist Ryszard Stroynowski, a principal investigator in the search for the Higgs and the leader of SMU’s team from the Department of Physics on the experiment.

“The experimental physics group at SMU has been involved since 1994 and is a major contributor to this study. This discovery was many years in the making, but it was worth the wait,” Stroynowski said.

The results, which are preliminary, were announced at CERN, the European Organization for Nuclear Research, near Geneva, Switzerland, and at the International Conference of High Energy Physics in Melbourne, Australia.

SMU Dean of Dedman College of Humanities and Sciences William M. Tsutsui noted that the crucial work contributed by SMU scientists gives Dallas standing in the discovery.

“Although the world’s eyes are on Switzerland, it is important to remember how much of the expertise driving the revolutionary experiments at CERN came from right here in Dallas,” Tsutsui said. “Distinguished scholars in Dedman College’s Department of Physics, including Ryszard Stroynowski and Jingbo Ye, have played critical roles in the search for the tiniest and most elusive building blocks of the universe.”

Observation is culmination of nearly 50 years of research
In making the announcement, CERN’s scientists stopped short of declaring the new particle the Higgs, saying they will further analyze the data to see whether it is the Higgs boson as originally theorized more than 40 years ago, but which has never been observed through experiments.

A Higgs particle is necessary to round out the fundamental particles that make up physics’ Standard Model, which describes the fundamental particles and their interactions.

Without a Higgs, the Standard Model does not fully explain how the universe emerged from the Big Bang. The Higgs explains how matter acquires mass.

CERN’s Large Hadron Collider along the border of France and Switzerland made it possible to observe evidence of the Higgs by smashing together protons at high energies so their breakup replicates the Big Bang. The LHC, which took a decade to build, started operation in 2010. It is home to the largest high-energy physics experiments in the world, including the ATLAS and CMS particle detectors, which supplied the data for Wednesday’s results.

Scientists from 45 collaborating nations work on the LHC experiments, including more than 1,700 from 89 U.S. universities. They have helped design, build and operate the LHC accelerator and its particle detectors.

LHC’s data equivalent to grains of sand needed to fill Olympic-size pool
The LHC is a 17-mile tunnel some 100 meters below ground. Within the tunnel, billions of protons are sent hurling into one another to re-create the high-energy explosions present at the Big Bang. In those rare instances when protons collide in the LHC tunnel, the smashing protons break up into smaller particles. In a process akin to reverse engineering, the resulting particle sprays are captured as data that are then analyzed for evidence that they emerged from the fundamental Higgs.

In announcing the results, CERN scientists said data taken the past two years represent 500 trillion collisions. That equates to the grains of sand it would take to fill an Olympic-size swimming pool. Within that data, evidence pointing to the Higgs equals an amount of sand covering the tip of a finger, they said.

Discovery made possible by global supercomputing grid that includes SMU
Credit for the discovery goes not only to the scientists and to CERN’s Large Hadron Collider, but also to a vast worldwide computing grid at partnering institutions. Physicists rely on supercomputers to assist their analysis of the massive flow of raw data containing the Higgs.

The SMU High-Performance Computing system is part of that grid and routinely runs data that contributed to the observation, Stroynowski said.

“Much of the success of our small group in the highly competitive environment of a large international collaboration has been due to an easy access and superb performance of the SMU High Performance Computing system,” Stroynowski said. “We used the HPC for fast data analyses and complex calculations needed for the discovery.”

Discovery of the new particle demonstrates the importance of basic research, said James Quick, associate vice president for research at SMU and dean of graduate studies.

“SMU is proud and excited that its Department of Physics has been an active participant in this effort and looks forward to the department’s continued participation at CERN,” he said. “Launched by a federal research project sponsored by Congressman Pete Sessions, high-performance computing at SMU played a role in the Higgs discovery and is a primary focus in the university’s drive to expand research and enhance education.”

Discovery is once-in-a-lifetime milestone for SMU researchers
SMU researchers contribute to the experiment through hardware and software development, as well as by taking operations shifts, both in the control room and in the United States, by remote, and through review of their colleagues’ work.

Besides Stroynowski, the SMU team includes Physics Department researchers Jingbo Ye, Ryan Rios and Julia Hoffman. In addition, physics faculty Robert Kehoe and Stephen Sekula are part of the SMU team. Theoretical faculty include Pavel Nadolsky and Fredrick Olness.

“It’s a very happy day for all of us in particle physics,” said Nadolsky, who with other physicists contributed calculations extensively used by LHC experimentalists, including for discovery of the Higgs boson candidate and for ongoing analyses to establish the properties of the new particle. Those working with him include postdoctoral researchers Marco Guzzi and Jun Gao, graduate student Zhihua Liang, and senior lecturer Simon Dalley.

Other researchers who have participated on the SMU team include Ana Firan, Haleh Hadavand, Sami Kama, Aidan Randle-Conde, Peter Renkel, Rozmin Daya, Renat Ishmukhametov, Tingting Cao and Kamile Dindar-Yagci.

Electronics development was carried out by research professors Andy Liu and Annie Xiang, with computer support by Justin Ross.

“The discovery of the Higgs is a once-in-a-lifetime event; this is the culmination of a 50-year quest,” said Olness, chair of the SMU Physics Department. “The last time a discovery of this import occurred was in 1983 with the observation of the W and Z boson — also at CERN; this achievement was recognized with the 1984 Nobel Prize. Many speculate the discovery of the Higgs boson also merits a Nobel Prize.”

The vast majority of U.S. scientists participate in the LHC experiments from their home institutions, remotely accessing and analyzing the data through high-capacity networks and grid computing.

“The results released on July 4 are truly a ‘team effort,’ not just by SMU but throughout all of ATLAS,” said Sekula, assistant physics professor. “These results are not possible without both the cooperation and competition that are needed to drive scientific innovation and progress.”

Waiting for Higgs for more than half a century
Physicists theorized in 1964 the existence of a new particle, now known as the Higgs, whose coupling with other particles would determine their mass.

SMU’s Kehoe said the observation changes our view of the universe. “It further transforms our daily experience of mass, which is hard and heavy, into the ghostly world of quantum mechanical interactions,” Kehoe said. “If what we are seeing is the Higgs particle, we will have identified the last unknown particle in the Standard Model.”

The Standard Model of particle physics has proved to explain correctly the elementary particles and forces of nature through more than four decades of experimental tests. But it cannot, without the Higgs boson, explain how most of these particles acquire their mass, a key ingredient in the formation of our universe.

CERN reported that both the ATLAS and CMS experiments within the LHC independently observed the new heavy particle in the mass region around 125-126 billion electron volts.

“So far, more than one study indicates an excess, but by a bit more than expected,” Kehoe said. “And the mass is in the range predicted for a Standard Model Higgs. However, measurements from other analyses need also to be brought to bear.”

The preliminary results announced Wednesday are based on data collected in 2011 and 2012, with the 2012 data still under analysis. A more complete picture will emerge later this year after the LHC provides more data.

Scientists to gather more data to learn about new particle
Sekula, who was at CERN and live-blogged Wednesday’s announcement, reported that “the atmosphere in the Main Amphitheater at CERN was electric, and all this energy burst forth in thunderous applause when first CMS, then ATLAS, showed independent and overwhelming evidence for the existence of a new particle in nature, consistent with the Higgs particle. Decades of scientific hope and frustration suddenly turned to joy and excitement — I can only imagine what the future holds as we gather more data and learn more about this particle.”

The CMS and ATLAS experiments in December announced seeing tantalizing hints of a new particle in their hunt for the Higgs. Since resuming data-taking in March 2012, the CMS and ATLAS experiments have more than doubled their collected data.

In the future, physicists will have to determine the properties of the new particle.

“How much does it weigh precisely? What are its quantum mechanical properties?” Kehoe said. “There are several theories that are consistent with what we’ve seen so far, like the theory of supersymmetry, and we need to make careful measurements to tell which one is correct. If what we’re seeing is a new type of particle that only superficially resembles the Higgs right now, then this will revolutionize our understanding of matter and energy at a fundamental level.” — Margaret Allen, CERN, Fermilab

Follow SMUResearch.com on Twitter, http://twitter.com/smuresearch.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smuresearch.com.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the SMU Broadcast Studio, call SMU News & Communications at 214-768-7650.

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Fiber-optic data link, now with DOE funding, is critical in the hunt for Big Bang’s “God” particle

Tiny optoelectronic module plays a key role in the world’s largest physics experiments; new module will be 75 times faster than the current fiber-optic data link on Large Hadron Collider’s ATLAS experiment

The SMU fiber-optic data link (above) was made specifically for ATLAS and its extremely harsh low-temperature, high-radiation environment. More than 1,500 of the data link modules are installed on ATLAS. A second-generation link, which is five times faster but with a smaller footprint, is slated for the next upgrade of the LHC detectors. A planned third-generation data link, being funded by DOE, will be 75 times faster.(Credit: www.smuresearch.com)

A tiny optoelectronic module designed in part by SMU physicists plays a big role in the world’s largest physics experiment at CERN in Switzerland, where scientists are searching for the “God” particle.

The module, a fiber-optic transmitter, sends the Large Hadron Collider’s critical raw data from its ATLAS experiment to offsite computer farms. From there, thousands of physicists around the world access the data and analyze it for the long-sought-after particle, the Higgs boson.

Now as a result of SMU’s role on the LHC data link, SMU Physics Research Professor Annie Xiang has won a three-year research and development grant with $67,500 in support annually from the U.S. Department of Energy to advance the design of the optoelectronic module.

The grant calls for a customized multi-channel optical transmitter that can be deployed on many of the world’s high-energy particle detectors.

Xiang is principal investigator for SMU’s Data Links Group in SMU’s Physics Department, working in the Optoelectronics Lab of Physics Professor Jingbo Ye. She coordinates the lab’s development of optical data transmission systems for particle physics experiments.

More than 1,500 data link modules are installed on ATLAS
“We made the first-generation fiber-optic data link specifically for ATLAS and its extremely harsh low-temperature, high-radiation environment,” Xiang said.

More than 1,500 of the first-generation data link modules are installed on the calorimeter detectors of ATLAS. The link’s job is to reliably offload a continuous flood of raw data without failure or error. Scientists scour the data for signs of the Higgs boson, which has been theorized for decades but never actually observed. It is believed the Higgs gives mass to the matter that we observe.

A second-generation data link, which SMU also helped design, is slated for deployment in the next upgrade of the LHC in coming years. The current data link installed in ATLAS can transmit up to 1.6 gigabits a second in a single channel, which equates to writing an HD DVD in one minute, Xiang said. The second-generation link, a 5 gigabit transceiver, has a smaller footprint than the current link, but can transmit three times faster and is qualified for even higher radiation. “Many thousands of the second-generation link can be expected across the LHC detectors,” Xiang said.

The data link being supported by DOE will be even faster. A transmitter only, it will have a transmission capacity of 120 gigabits a second, or 75 times faster than the data link currently installed on ATLAS, Xiang said.

DOE project will customize off-the-shelf commercial components for on-detector installation
To design the links, SMU’s team and its collaborators start with qualified commercial transmitters and receivers, then customize them for the LHC detectors, Xiang said. They will repeat that process to develop the data link being supported by DOE.

Called a “generic” module, the link supported by DOE isn’t specified for any particular detector, but rather will be available to deploy on detectors at the LHC, at Fermi National Accelerator Laboratory (Fermilab) and others.

The module — a 12-channel transmitter — must be high speed and low footprint, and able to withstand an extremely cold and high-radiation environment, while at the same time maintaining low mass and low power consumption, Xiang said.

The DOE award is part of a collaborative project with Fermilab, the University of Minnesota, The Ohio State University and Argonne National Laboratory, with a total funding of $900,000. SMU designed the first-generation module in collaboration with Taiwan’s Academia Sinica. SMU collaborated on the second-generation module with CERN, Oxford University and Fermilab.

Ye and Xiang are members of SMU’s ATLAS team, which is led by SMU Physics Professor Ryszard Stroynowski. — Margaret Allen

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smuresearch.com.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the SMU Broadcast Studio, call SMU News & Communications at 214-768-7650.

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SMU physicists at CERN find hints of long sought after Higgs boson — dubbed the fundamental “God” particle

Subatomic particle can explain why matter has mass

In a giant game of hide and seek, physicists say there are indications they finally may have found evidence of the long sought after fundamental particle called the Higgs boson.

Researchers at Switzerland-based CERN, the largest high-energy physics experiment in the world, have been seeking the Higgs boson since it was theorized in the 1960s.

The so-called “God” particle is believed to play a fundamental role in solving the important mystery of why matter has mass. (article continued below)

“It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” — physicist Richard Feynman

By Fredrick Olness
Chairman and Professor
SMU Department of Physics

A 50 year search for the origin of particle mass nears an end. Maybe.

Mass is a seemingly simple property of everyday objects — atoms, humans, coffee cups. Yet, to understand the origin of mass on a fundamental level has been a challenging problem with a long history. The solution to this problem, suggested nearly 50 years ago, was the Higgs Boson (or just Higgs, for short). However, it has yet to be discovered.

On Tuesday, Dec. 13, 2011, an end to the Higgs search appeared much closer when the CERN Laboratory in Geneva, Switzerland presented the latest results from the Large Hadron Collider (LHC) in a colloquium broadcast around the globe on the World Wide Web.

The announcement was a joint presentation by researchers from ATLAS and CMS, the two largest independent experiments at the LHC, in which they presented evidence for the Higgs based on the results of their 2011 data set.

Both the ATLAS and CMS experiments observed evidence for the Higgs. While the evidence was significant, it was not yet sufficient to claim an unambiguous discovery; however, it is quite compelling that the Higgs mass range obtained by these two independent experiments is consistent.

These results represent a tremendous step forward in explaining why fundamental particles have mass, and whether the Higgs exists.

What is the Higgs boson?
The postulated Higgs boson is responsible for giving mass to the many fundamental particles that make up the universe. This includes the quarks that comprise protons and neutrons, which comprise atoms and molecules, which comprise humans and everything around them. In essence, the Higgs generates the mass of the fundamental particles that make up you and your coffee cup.

We know objects have mass — just lift a heavy suitcase or weigh yourself on a scale. But to explain this seemingly simple idea in the context of our current fundamental theories has been a struggle ever since the idea of the Higgs was introduced 50 year ago. The problem is that to give particles mass in a straightforward manner would spoil a particular symmetry of the theory known as the “gauge symmetry.” Who cares? you ask, and why should I be worried about symmetry?

Symmetries have been an important guiding aspect of physics dating back before Einstein, who used symmetry principles, in part, to conclude that “all reference frames are created equal,” which led to his Theory of Relativity — certainly one of the triumphs of the 20th Century.

And that is what is so special about the Higgs; it gives particles a mass without violating the rules of symmetry.

How does the Higgs solve the problem?
According to our current understanding, Higgs bosons permeate all of space. As fundamental particles move through space, Higgs bosons interact with the particles and effectively exert a drag on them; it is this drag effect which we interpret as the mass of the particle.

Consider the following experiment. First move your coffee cup through the air, and then repeat this motion underwater; the water provides more resistance on the cup and it “feels more massive” as you drag it through the water as compared to the air. It is the interaction between the water and the coffee cup that provides the resistance to motion of mass. In this analogy, the water is playing the role of the Higgs.

It is the same with a quark, one of the fundamental particles that matter is made from. As a quark moves through space it interacts with the Higgs, and this interaction exerts a drag on the quark so that it “feels heavy.” But this is an illusion; in the strict interpretation of the theory, the quark has “mass” only because of the interaction with the Higgs that simulates the effects of the weight.

DÉJÀ VU: Luminiferous aether
To recap, the current theoretical picture is that Higgs bosons are everywhere. They permeate all space, and they must exist so that fundamental particles (that make up you and your coffee cup) have mass.

Have we seen this situation before?

In the late 1800’s, physicists posited the existence of a “luminiferous aether” which permeated all space. Scientists knew that water waves traveled through water, sound waves through air, and so they believed that light waves also needed something to travel through; luminiferous aether was invented to serve this purpose and get the “right” answer. There were many experiments that gave indirect evidence for the aether; however, all attempts to directly measure it were unsuccessful. Eventually it was demonstrated that the luminiferous aether did not exist, and this paved the way for Einstein to show that it was unnecessary and to present an alternative, his theory of relativity.

Thus, the non-existence of luminiferous aether actually led to more fantastic discoveries than if it had been proven.

Direct vs. indirect evidence
So we come to the central question: does the Higgs exist?

There is ample indirect evidence that the Higgs exists. We know that fundamental particles have mass, and we believe this mass is due to particle interactions with Higgs bosons. Over the past 50 years physicists have performed a variety of sophisticated experiments, and they all point to the existence of the Higgs.

However, in many ways the Higgs is a contrived solution; inelegant, introduced into the theory because so far there has been no better way to get the right answer — that particles have mass.

Just because it is currently the only solution developed does not mean it is the one that nature chooses.

And that is why we need direct evidence of the Higgs; we need to produce an actual Higgs in the laboratory, study its properties, and verify our theoretical view of the world with cold, hard facts from experimental observation.

The 2011 LHC results
The LHC experiment is producing these facts and evidence.

If the Higgs is confirmed to exist, it would validate our theory of how particles acquire mass, and serve as the foundation for myriad experiments in the future. Many speculate this discovery would also warrant a Nobel Prize.

If the Higgs is confirmed to not exist, it would likely send many theorists back to the drawing board in hopes of finding that nature has an even more clever mechanism of how particles acquire mass than we have yet been capable of conceiving. And, just as the non-existence of the aether set the stage for relativity, the non-existence of the Higgs could set the stage for future surprises.

Either way it will be an exciting journey and the results from the LHC bring us one step closer to the answer.

Fredrick Olness is a theoretical physicist at SMU studying Quantum Chromodynamics (the fundamental force that binds nuclei) to help answer the questions: What are the fundamental building blocks of nature, and what holds them together?

Thousands of scientists from around the world seek evidence of the Higgs particle through experiments at CERN’s Large Hadron Collider. The researchers analyze a flood of electronic data streaming from the breakup of speeding protons colliding in the massive particle accelerator. Scientists on Tuesday announced in a seminar held at CERN that they’ve found hints of the Higgs.

“Now we have a strong indication, but not yet a confirmation, of a discovery,” said Southern Methodist University physicist Ryszard Stroynowski, the leader of SMU’s team of scientists working on the experiment.

Higgs: Attempting to discover Standard Model’s missing piece
Theorists have predicted that some subatomic particles gain mass by interacting with other particles called Higgs bosons. The Higgs boson is the only undiscovered part of the Standard Model of physics, which describes the basic building blocks of matter and their interactions.

Higgs bosons, if they exist, are short-lived and can decay in many different ways. Just as a vending machine might return the same amount of change using different combinations of coins, the Higgs can decay into different combinations of particles. Discovery relies on observing statistically significant excesses of the particles into which they decay rather than observing the Higgs itself.

“If indeed we are able to confirm sighting of the Higgs in the months ahead, this clearly focuses our future studies,” said Stroynowski, a professor in the SMU Department of Physics. “Now by the middle of next year we’ll know for sure if this particle exists and we can begin to study its properties. This is a very big step in the understanding of particle physics.”

SMU researchers contributed to the results announced Tuesday by CERN
Besides Stroynowski, the SMU team of researchers includes three other Physics Department faculty: Jingbo Ye, Robert Kehoe and Stephen Sekula, six postdoctoral fellows and five graduate students. Main contributions to the new analysis of the data were made by postdoctoral researcher Julia Hoffman and graduate student Ryan Rios.

Others in the department who have contributed include former postdoctoral fellow David Joffe, now an assistant professor at Kennesaw State University, graduate students Renat Ishmukhametov and Rozmin Daya and theoretical faculty Fredrick Olness and Pavel Nadolsky.

Stroynowski, Hoffman, and Rios are among the more than 70 scientists whose work directly contributed to the conference papers reporting the findings, said Olness, a professor and chairman of the SMU Department of Physics.

While thousands of scientists worldwide participated directly and indirectly in the experiments, SMU is one of only a few U.S. universities whose scientists are named among the 70 researchers directly cited on one of the three conference papers.

“Professor Stroynowski has demonstrated extraordinary scientific leadership in keeping our relatively small Department of Physics at SMU engaged in one of the most significant scientific experiments of our time,” said Jim Quick, SMU Associate Vice President for Research.

SMU’s role in the LHC experiments provides SMU students a chance to participate in pioneering discoveries, said Olness.

“SMU students helped build the ATLAS detector, they were in the control room when the experiment started up, and they contributed to the analysis,” he said. “The results presented today are historic, and they will help shape our view of the matter and forces that comprise our universe; SMU students have played a role in this achievement.”

Higgs discovery would confirm decades-old theory

Discovering the type of Higgs boson predicted in the Standard Model would confirm a theory first put forward in the 1960s.

“This year, the LHC has come roaring into the front of the hunt for the Higgs boson and may be poised to either identify it, or refute its existence, in the coming months,” said Robert Kehoe, associate professor in the SMU Department of Physics. “As I like to tell my students learning modern physics, ‘You still live in a world in which we do not know for sure the mechanism breaking the symmetry between electromagnetic and weak interactions. That world may be soon to change forever. We may soon see a truly new thing.’”

Even if the LHC experiments find a particle where they expect to find the Higgs, it will take more analysis and more data to prove it is a Standard Model Higgs, according to CERN researchers. If scientists found subtle departures from the Standard Model in the particle’s behavior, this would point to the presence of new physics, linked to theories that go beyond the Standard Model. Observing a non-Standard Model Higgs, currently beyond the reach of the LHC experiments with the data they’ve recorded so far, would immediately open the door to new physics, said an official statement from CERN.

Results constrain Higgs’ mass to a range more limited than before

In announcing the findings, CERN noted that two experiments at the LHC have nearly eliminated the space in which the Higgs boson could dwell. The ATLAS and CMS experiments see modest excesses in their data that could soon uncover the famous missing piece of the physics puzzle, the scientists said.

The experiments’ main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 giga-electron-volts (GeV) by the ATLAS experiment, and 115-127 GeV by CMS. Tantalizing hints have been seen by both experiments in this mass region, but these are not yet strong enough to claim a discovery.

Both ATLAS and CMS have analyzed several decay channels, and the experiments see small excesses in the low mass region that has not yet been excluded.

Taken individually, none of these excesses is any more statistically significant than rolling a die and coming up with two sixes in a row. What is interesting is that there are multiple independent measurements pointing to the region of 124 to 126 GeV. It’s far too early to say whether ATLAS and CMS have discovered the Higgs boson, but these updated results are generating a lot of interest in the particle physics community.

The experiments revealed the latest results as part of their regular report to the CERN Council, which provides oversight for the laboratory near Geneva, Switzerland.

Experiments in coming months will refine the analysis
More than 1,600 scientists, students, engineers and technicians from more than 90 U.S. universities and five U.S. national laboratories take part in the ATLAS and CMS experiments. The Department of Energy’s Office of Science and the National Science Foundation provide support for U.S. participation in these experiments.

Over the coming months, both the ATLAS and CMS experiments will focus on refining their analyses in time for the winter particle physics conferences in March. The experiments will resume taking data in spring 2012.

Another possibility, discovering the absence of a Standard Model Higgs, would point to new physics at the LHC’s full design energy, set to be achieved after 2014. Whether ATLAS and CMS show over the coming months that the Standard Model Higgs boson exists or not, the LHC program is closing in on new discoveries. — CERN, Southern Methodist University

SMU is a member of the ATLAS experiment at the LHC. It takes a large team of scientists to search for the Higgs and other new physics; the SMU delegation includes faculty members Ryszard Stroynowski, Jingbo Ye, Robert Kehoe, Stephen Sekula, and a number of research professors, postdoctoral fellows and graduate students.

In addition, recent SMU ATLAS contributors include postdoctoral fellows Julia Hoffman, David Joffe (now at Kennesaw State), Ana Firan, Haleh Hadavand, Sami Kama, Aidan Randle-Conde and Peter Renkel, and graduate students Ryan Rios, Rozmin Daya, Renat Ishmukhametov Tingting Cao and Kamile Dindar-Yagci. Theoretical support was provided by faculty member Pavel Nadolsky, electronics development by research professors Andy Liu and Annie Xiang, and computer support by Justin Ross.

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Softpedia headlines world’s fastest chip designed by SMU physicists

The popular web site Softpedia has written about SMU’s new “world’s fastest integrated circuit” designed for use in the challenging environment of the Large Hadron Collider.

The circuit was designed by physicists in SMU’s Department of Physics. Softpedia science editor Tudor Vieru writes about the major advancement in an April 9 post “LHC to Receive Fastest Integrated Circuits Ever Made.”

The popular web site Softpedia has written about SMU’s new “world’s fastest integrated circuit” designed for use in the challenging environment of the Large Hadron Collider.

The circuit was designed by physicists in SMU’s Department of Physics. Softpedia science editor Tudor Vieru writes about the major advancement in an April 9 post “LHC to Receive Fastest Integrated Circuits Ever Made.”

Jingbo%20Ye%20SMU%20microscope.jpg
Jingbo Ye views SMU LOC serializer

The site, popular for software downloads and science and technology information, noted that the job of the new high-speed integrated circuit was designed for the LHC’s high-radiation environment, as well as for high data bandwidth, low-power dissipation and extremely high reliability. SMU physicist Jingbo Ye, an associate professor of physics, led development of the circuit.

Excerpt:
By Tudor Vieru
Science Editor
A group of experts from the Southern Methodist University (SMU), in Dallas, announces the development of a new, super-fast circuit designed specifically to augment the capabilities of one of the main particle detectors of the Large Hadron Collider. The LHC is the largest physics experiment ever designed, and its goal is to discover some of the most fundamental knowledge about the Universe and the elementary particles and forces that govern our world.

With the development of the new integrated circuits, called “link-on-chip” or LOC serializer circuits, the team hopes to be able to boost the performances of the LHC’s ATLAS particle detectors, one of the three main instruments in the 27-kilometer-long tunnel of the accelerator. The innovation was designed specifically to be used by the Liquid Argon Calorimeter, an ATLAS sub-detector that could function a lot better, and overall more efficiently, once the new application-specific integrated circuits (ASIC) are added. The SMU team is directly involved in the ATLAS collaboration.

There was a large number of factors researchers at the university needed to consider when creating the LOC. In addition, the large amount of radiation that is produced as the LHC collides beams of protons head-on at the highest energy levels ever achieved, there are also other issues to consider. The calorimeter needs to be able to handle a high data bandwidth, low power dissipation, and must feature an extremely high degree of reliability as well. There is very little room for error in an endeavor such as the LHC, and all of its components need to respect a vast array of norms and rules.

Read the full story

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New high-speed integrated circuit for world’s biggest physics experiment is fastest of its kind

CERN%20black%20hole%20thumb.jpg
This simulated black hole from ATLAS proton collisions would quickly decay into particle debris. Credit: CERN

A new high-speed integrated circuit to reliably transmit data in the demanding environment of the world’s largest physics experiment is the fastest of its kind.

This new “link-on-chip” — or LOC serializer circuit — was designed by physicists at Southern Methodist University in Dallas as a component for use in a key experiment of the Large Hadron Collider particle accelerator in Europe.

The miniscule SMU LOC serializer was designed for ATLAS, which is the largest particle detector at the Large Hadron Collider.

Jingbo%20Ye%20SMU%20microscope.jpg
Jingbo Ye views SMU LOC serializer

The LHC, as it’s called, is a massive, high-tech tunnel about 100 meters underground. Within the LHC’s circular, 17-mile-long tunnel, protons traveling at high energy are smashed together and broken apart so physicists worldwide can analyze the resulting particle shower detailed in a flood of electronic data.

Data holds key to bold new physics discoveries
The data transmits from the LHC via a tiny serializer circuit enabling electronic readouts. Physicists analyze the data to discover answers to unsolved scientific mysteries such as the Big Bang, dark matter, black holes, the nature of the universe and the Higgs particle that gives mass to quarks and electrons. SMU is a member of the ATLAS Experiment.

The LHC is a program of the Geneva-based international scientific consortium known as the European Organization for Nuclear Research, or CERN. In March CERN announced that the LHC had successfully begun colliding protons at an energy three and a half times higher than previously achieved at any particle accelerator.

SMU LOC designers challenged by LHC’s formidable environment
SMU’s new world’s-fastest LOC serializer is what the industry calls an integrated circuit made for a specific use, or “ASIC” for application-specific integrated circuit. It was designed for the LHC’s high-radiation environment, as well as for high data bandwidth, low-power dissipation and extremely high reliability, said physicist Jingbo Ye. An associate professor of physics, Ye led development of SMU’s LOC serializer.

More SMU Research

Simulating the Big Bang

Glimpse of dark matter?

Hunt for Higgs boson

The SMU LOC serializer was perfected over the past three years in the SMU Research Laboratory for Optoelectronics and ASIC Development in the Department of Physics. An added feature of the SMU LOC serializer is that it can operate at cryogenic temperatures and has been tested down to liquid nitrogen temperatures of -346 degrees Fahrenheit.

It was designed to transmit data for the optical link readout system of the ATLAS Liquid Argon Calorimeter, an ATLAS sub-detector that measures the energies of electrons and photons generated at the center of ATLAS where protons collide. Because the electronic readout components are in the center of the ATLAS detector, they are essentially inaccessible for routine maintenance, so reliability is paramount, Ye said.

Serializer transmits data shower from colliding protons
With a data transmission rate of 5.8 billion-bits per second, the SMU LOC serializer represents the first milestone for the SMU-led team. The team plans to develop an even faster ASIC serializer that transmits data at up to 10 billion-bits per second. Faster circuits are critical as CERN continues increasing the LHC’s luminosity, thereby generating more and more data.

“SMU’s LOC serializer is the fastest in our field for the moment,” Ye said. “CERN is developing another fast ASIC serializer that does not yet match our speed. SMU’s next goal is to increase both the data speed and the number of data lanes to produce an even faster LOC serializer. In the next few years, we hope to increase the total speed by a factor of 62 more than what is installed in ATLAS.”

Ye presented the SMU LOC serializer design in February at CERN. Made of complementary metal-oxide-semiconductor transistors in silicon-on-sapphire, the serializer’s design details also will be presented to scientists in April in Hamburg during the ATLAS Upgrade Week at the DESY laboratory, Germany’s premier research center for particle physics. The SMU LOC serializer research was funded by the National Science Foundation and the U.S. Department of Energy.

The existing LOC serializer in use at present in the ATLAS Liquid Argon Calorimeter was previously developed and installed by an SMU-led team of physicists and engineers from France, Sweden, Taiwan and the United States.

Faster serializer a critical component for Super LHC
SMU’s new LOC serializer is critical for the upgrade of the Large Hadron Collider, called the Super LHC, which is planned to go online in 2017, Ye said.

“The original ATLAS design used a commercial serializer that was purchased from Agilent Technologies,” Ye said. “But for the Super LHC there is no commercial device that would meet the requirements, so — being typical physicists — we set out to design it ourselves.”

The ATLAS Liquid Argon Calorimeter’s existing optical link system, delivered by SMU physicists, has a data bandwidth of 2.4 terabits per second over 1,524 fibers, or 1.6 billion bits per second per fiber, more than 1,000 times faster than a T1 line of 1.544 megabits per second. The next generation of this optical link system will be based on the new SMU LOC serializer, and it will reach 152.4 terabits per second for the whole system.

More selectivity with faster data transfer
“Fast information transfer from the detector to the computer processing system is a necessity for handling the significantly increasing amounts of data expected in the next round of LHC experiments,” said Ryszard Stroynowski, U.S. Coordinator for the ATLAS Liquid Argon Calorimeter, and chair and professor of physics at SMU. “It will allow ATLAS to be more selective in the choices of events sent for further analysis.”

A radiation-tolerant, high-speed and low-power LOC serializer is critical for optical link systems in particle physics experiments, Ye said, noting that specialized ASIC devices are now common components of most readout systems.

“The ever increasing complexity of particle physics experiments imposes new and challenging constraints on the electronics,” Ye said. “The LOC serializer was a formidable task, but our team was up to the challenge.” — Margaret Allen

Related links:
Jingbo Ye
SMU Department of Physics
ATLAS
Large Hadron Collider
CERN: European Organization for Nuclear Research
CERN: Recipe for a Universe
Nobel Prize: Why is there something instead of nothing?
Fermilab: Dark Universe Debate

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Before God particle, scientists must learn soul of new machine

After a huge success in first testing, followed by a very public meltdown last September, the Large Hadron Collider may be ready for action again as early as June.

But before the science can proceed, the world’s scientists must come to terms with the complex organism they have created, says one project manager.

“We will have to understand the detector first,” says Ryszard Stroynowski, chair and professor of physics at SMU.

Stroynowski is U.S. Coordinator for the Liquid Argon Calorimeter, the literal and experimental heart of ATLAS, the largest particle detector in the LHC array.

Pictured right: Work progressing in the LHC tunnel.
Photo courtesy of CERN.

The first priority for operation of the ATLAS detector is “to get all those billions of elements to work together in synch again,” Stroynowski says. “We want to see during the summer whether the circulating beam will induce any noise in the system.”

Stroynowski leads an SMU delegation that includes Fredrick Olness, professor of physics, and Robert Kehoe and Jingbo Ye, assistant professors of physics, all in Dedman College. Kehoe is currently at CERN for his research.

The SMU team is focusing on three projects in parallel:

  • improvements of the graphic and software interfaces for control and monitoring of the detector and of the quality of its data
  • preparation of the software packages to analyze the data
  • design and prototyping of the modifications of the readout electronics that will be needed for future upgrades of the experiment to much higher-intensity beams — a six-year research and development project led by Jingbo Ye in SMU’s Physics Electronics Lab.

The LHC is considered the world’s largest physics experiment. The particle accelerator is a 27-kilometer circular tunnel that lies 100 meters underground near Geneva on the French-Swiss border. It uses a magnetic field to propel high-energy protons into each other.

A mechanical failure in September 2008 damaged 53 of the super-sized magnets that power and focus the accelerator’s beams. The final replacement magnet was lowered into place April 30. Repairs in the tunnel now focus on connecting the magnets together and installing new safety and monitoring systems to prevent similar incidents from happening again.

In addition, the 37 damaged magnets that were replaced by spares will be refurbished to serve as spares themselves. Sixteen magnets sustained only minimal damage and were repaired and reinstalled.

The earlier malfunction has resulted in a frustrating wait — one that has had a “rather demoralizing” effect on the students and postdoctoral fellows whose time at the LHC may come and go during downtime, Stroynowski says. Yet the importance of protecting the vast high-energy array from future trauma can’t be overstated, and “the goal is worth the wait, as the payoff may be enormous,” he says.

Scientists and technicians at the European Organization for Nuclear Research — called by its acronym, CERN — in Geneva have maintained an aggressive rehabilitation schedule. The ATLAS detector itself was closed on May 5, marking an end to checks and re-checks of the electronics, cables and other connections. Repairs to the accelerator’s underground ring are scheduled to be completed at the end of May.

Beams will start in June, initially at a relatively low 450 gigaelectron volts (GeV) per beam to ensure the integrity of the new parts and connections. Scientists will raise the energy over a couple of days to 2 teraelectron volts (TeV) per beam, and finally to the LHC’s target operational level of 5 TeV per beam.

The ATLAS team will start taking shifts in July and expects to have useful data starting in October 2009, Stroynowski says. The LHC will then run continuously for 11 months.

Stroynowski says he doesn’t expect any major discoveries by this time next year, but that he hopes “significant results” will come early in 2011.

The LHC’s proton collisions release even smaller pieces of matter, and the Atlas particle detector helps measure the tracks they leave. The huge, international project is directed at finding the “Higgs boson,” a subatomic “God particle” that physicists believe could help explain the origin of our Universe.

The theory behind the Higgs boson holds that all particles had no mass just after the “Big Bang.” As the Universe cooled and the temperature fell below a critical value, an invisible force field composed of subatomic particles called the “Higgs boson” developed throughout the cosmos. Particles that interact with the field gain mass and particles that never interact have no mass. But the theory remains unproven because no one has ever seen the Higgs boson at work. — Kathleen Tibbetts

SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with Dr. Stroynowski or to book him in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.

SMU is a private university in Dallas where nearly 11,000 students benefit from the national opportunities and international reach of SMU’s seven degree-granting schools. For more information see www.smu.edu.

Categories
Energy & Matter

Proton-smasher’s awaited flood of data creates big job for SMU researchers

At 10 p.m. on a Saturday night in April, a handful of SMU scientists continue working at the European Organization for Nuclear Research, called by its acronym CERN, in Geneva, Switzerland. A scattering of lights illuminates the windows in several buildings along the Rue Einstein, where researchers from dozens of countries and hundreds of institutions are combining their expertise on the Large Hadron Collider (LHC) — the biggest physics experiment in history.

Ryszard Stroynowski, chair and professor of physics at SMU, points out each building in succession to a group of visitors. “By October, every light in every one of these windows will be on all night,” he says.

By then, the LHC is expected to be fully tested and ready to work. When the largest particle accelerator ever constructed becomes fully operational, it will hurl protons at one another with precision to a fraction of a micron and with velocities approaching the speed of light. These conditions will allow physicists to recreate and record conditions at the origin of the universe — and possibly discover the mechanisms that cause particles in space to acquire their differences in mass.

For Stroynowski, who has worked for almost 20 years to help make the experiment a reality, words seem inadequate to capture the anticipation surrounding its imminent activation.

“It is somewhat like that of a 6-year-old kid on Christmas Eve, waiting for Santa Claus,” he says. “The time stretches almost unbearably long.”

The LHC will be the site of several experiments in high-energy physics with high-profile collaborators such as Harvard and Duke and national laboratories including Argonne, Brookhaven, Lawrence Berkeley and Fermilab. None of the experiments is more imposing than ATLAS, one of two general-purpose particle detectors in the LHC array. At about 42 meters long and weighing 7,000 tons, ATLAS fills a 12-story cavern beneath the CERN facilities in Meyrin, Switzerland, just outside Geneva. It is a tight fit: ATLAS overwhelms even the vast space it occupies. A catwalk, not quite wide enough for two people to stand side by side, encircles the device and allows an occasional dizzying view into its works.

Size Matters
The detector’s scale will help to focus and release the maximum amount of energy from each subatomic collision. A series of bar codes on each of its parts ensure that the detector’s components, whether palm-sized or room-sized, are aligned and locked with the perfect precision required for operability. Scientists from 37 countries and regions and 167 institutions participated in its design and construction.

As U.S. coordinator for the literal and experimental heart of the ATLAS detector — its Liquid Argon Calorimeter — Stroynowski is helping to finalize the last details of the detector’s operation in anticipation of the extensive testing, scheduled to begin in August. He leads an SMU delegation that includes Fredrick Olness, professor, and Robert Kehoe and Jingbo Ye, assistant professors in the SMU Department of Physics in Dedman College.

SMU scientists are completing work on the computer software interfaces that will control the device, which measures energy deposited by the flying debris of smashed atoms. A cadre of University graduate students and postdoctoral fellows also is working on data processing for ATLAS’ 220,000 channels of electronic signals, an information stream larger than the Internet traffic of a small country.

An estimated 53,000 visitors crowded the CERN facilities on the organization’s “Day of Open Doors” April 6, eager for a glimpse of the work that CNN International has named one of the “Seven Wonders of the Modern World.”

At the beginning of May, the areas were sealed off in preparation for the first round of testing. Computers will remotely control the ATLAS experiment, which will not be touched by human hands because of the radiation released by the atomic collisions. Safety is the reason for the elaborate lockdown procedure involving more than 80 keys, each coded to a different individual’s biometric data. The system is designed to lock out any use of the device if even one key is unaccounted for.

“ATLAS has been built to run for at least 15 years with no direct human intervention,” Stroynowski says. “It will be as if we have shot it into space.”

Currently, the initial test run is scheduled to begin Sept. 1.

The Waiting Game
Once data start streaming in, the game of expectations management begins. The ATLAS detector will produce a staggering amount of raw information from each collision, and the most useful bits will be few and far between. Out of 40 million events per second, the researchers hope to pinpoint 10 events a year. The challenge seems a little like looking for a needle in a haystack the size of Mars.

“We may get what we’re looking for on the first try, or it may take us three years to find anything we can use,” Stroynowski says. “A big part of our job is to make sure we’re ready when we do.”

Among those entrusted with that task are graduate students and postdoctoral fellows in SMU’s Physics Department, including Rozmin Daya, Kamile Dindar, Ana Firan, Daniel Goldin, Haleh Hadavand, Julia Hoffman, Yuriy Ilchenko, Renat Ishmukhametov, David Joffe, Azeddine Kasmi, Zhihua Liang, Peter Renkel, Ryan Rios and Pavel Zarzhitsky.

“I came to SMU for postdoctoral work specifically because of the department’s involvement in the ATLAS project,” says David Joffe, a native of Canada who received his Ph.D. in physics from Northwestern University. “For particle physicists, being part of this is really a once-in-a-lifetime opportunity.”

For Julia Hoffman, who received her doctorate from Soltans Institute for Nuclear Studies in her native Poland, that opportunity has meant expanding her own horizons.

“I learn new, and I mean really new, things every day,” she says. “Different programming languages, different views on physics analysis. I’m learning how it all works from the inside. I work with students and gain new responsibilities. This kind of experience means better chances to find a permanent position that will be as exciting as this one.”

The SMU group works with formulae based in Monte Carlo methods, the “probabilistic models that use repeated random sampling of vast quantities of numbers” to impose a semblance of order on the chaos created when atoms forcibly disintegrate. Results are highly detailed simulations of known physics that will help make visible the tiny deviations researchers hope to detect when ATLAS begins taking data.

These unprecedented computing challenges also have become an impetus for new SMU research initiatives. James Quick, SMU associate vice president for research and dean of graduate studies, hopes to contain ATLAS’ vast data-processing requirements with a large-capability computing center located on campus.

Quick visited CERN in April to discuss the details with Stroynowski and other key personnel. The proposed center would provide a first-priority data processing infrastructure for SMU physicists and a powerful new resource for researchers in other schools and departments. During the inevitable LHC downtime, as beams are calibrated and software is debugged, the SMU center’s computing power would be available for campus researchers in every field across engineering, the sciences and business.

“The ATLAS experiment presents an opportunity for the University to step up in a big way, and one that will benefit the entire campus,” Quick says.

He envisions a data processing farm of 1,000 central processing units, each connected to an Internet backbone to allow the fastest possible return on SMU’s ATLAS input. Speed and access are the keys, Stroynowski says, paraphrasing Winston Churchill: “The winner gets the oyster, and the runner-up gets the shell.”

Those who have made their careers in high-energy physics are well aware of the stakes involved in the LHC, he adds, and being the first to process certain data could separate a potential Nobel Prize winner from those who will make the same discovery a day late.

As a group, high-energy physicists are accustomed to taking the long view — and for SMU researchers, the long view has been especially helpful. The ghost of the Superconducting Super Collider, which would have made its home in North Texas, still shadows the recent triumphs at CERN.

The SSC brought Stroynowski to the University, and its 1993 demise through congressional defunding was the impetus for the LHC project. The questions haven’t gone away because the experiment has changed venues, Stroynowski says. Yet even now, as the first test nears, his anticipation is tempered by caution.

“I don’t think we’ll get a beam all the way around [the LHC tunnel] on the first try,” he says.

Indeed, the subject of whether scientists will achieve a beam collision during the first tests or after additional calibration has been the subject of a few lively wagers.

“I think we’ll have to wait at least a few more weeks for that milestone,” he adds. “But in this case, I’ll be more than happy to be wrong.” — Kathleen Tibbetts

SMU has an uplink facility on campus for live TV, radio or online interviews. To speak with Dr. Biehl or Dr. D’Mello or to book them in the SMU studio, call SMU News & Communications at 214-768-7650 or UT Dallas Office of Media Relations at 972-883-4321.

SMU is a private university in Dallas where nearly 11,000 students benefit from the national opportunities and international reach of SMU’s seven degree-granting schools. For more information see www.smu.edu.