Categories
Culture, Society & Family Energy & Matter Researcher news Student researchers

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

Categories
Earth & Climate Energy & Matter Researcher news

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

Categories
Energy & Matter Researcher news

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.

Follow SMUResearch.com on Twitter.

For more information, www.smuresearch.com.

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.smu.edu.

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 studio, call SMU News & Communications at 214-768-7650.

Categories
Researcher news Student researchers Technology

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.

Categories
Energy & Matter Researcher news Technology

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.