There are many sides to being a physicist, some of them are good, and some bad. Recently I’ve had the chance to experience the three best reasons to be a research physicist, and they are discovery, collaboration and travel. Recently, I traveled to Beijing to present my work on the decays of the Ds meson at the Charm 2010 conference.
This was an opportunity to show the physics community how I spent my PhD years and what discoveries I had made. The great part was that I got to make four different measurements, and have the thrill of discovery four times! The puzzle I was trying to solve was seemingly simple. The Ds meson should decay at a fixed rate, and theorists can predict this rate using advanced models. When I started this analysis in 2008 the theory and experiment disagreed significantly, which was a serious problem for physicists. Charm mesons decays are supposed to be clean and easy to predict and measure using quantum chromodynamics, and yet the predictions missed by four standard deviations. So I joined a team of physicists to measure the leptonic decays of the Ds meson to answer the question once and for all. The measurements I made were competitive, better than the world average at the item. They were consistent with what we had already seen, and they didn’t seem to solve the problem from the experimental side. Fortunately (or unfortunately, depending how you see these things) the theorists had improved their models and updated their predictions, and once again the theory and experiments matched. Having the chance to go to Charm 2010 not only allowed me to present my findings to the world, but it also allowed me to see what the other scientists had discovered. Everybody agreed that the results were impressive and that the hard work of the theorists was worthwhile, and that this curious journey probing the Ds mesons was at an end, at least for now.
What lifted my spirits most about the conference was the sense of collaboration that everybody felt. They had all come together because they care about charm physics, one of the least fashionable areas of particle physics, so they were all enthusiastic. The talks were fascinating, followed by curious questions and side discussions. The talks covered every aspect, from recent discoveries to long standing theoretical problems to new experiments which are currently being developed. This kind of collaboration, even in the face of competition, is something that isn’t seen in many other areas of work. We have physicists from dozens of countries, speaking dozens of languages, and from hundreds of universities, who come together to share their ideas and work. They disagree, and when they do their debates can be heated, but they only do this because they love their work, and deep down they all agree that no matter what an individual believes about a discovery, the data itself has the final word. Whenever I think about how physicists bond over their frustrations or joys I’m taken back to a meeting at Elba. Some politicians had joined the meeting for a day and gave a short speech about cooperation across borders, and how inspired he felt looking at the physicists, and how he wished this was also possible in the realm of politics. Hearing this, I realized that there is something fundamentally important about international collaboration. It’s not just useful for the progress of science, it opens up new opportunities for people and nations to work together. If it’s in the interests of the USA and Italy to let their scientists travel freely to share their work, then we can be sure that this is going to have far reaching consequences for relationships between these nations.
The real adventure began shortly afterwards, as I took this trip as a unique opportunity to journey across Russia via the trans-Mongolian express, something I’ve wanted to do ever since I first heard of the railway. The journey takes about a week, and passes through some of the most breathtaking scenery in the world, including Lake Baikal, the largest freshwater lake on Earth. The journey is rich in history, geology and culture, across 5,000 miles from Beijing to Moscow. Of course, there were great sights to be seen, including the Forbidden City in Beijing and the Kremlin in Moscow, as well as the gauge transformation at the Sino-Mongolian border. Taking time off from work like this is vital for research, as it gives us time to think things over at a slower pace. On the way back, I couldn’t help thinking about the Bc meson and what kinds of mysteries it might hold. It was also something of a watershed in my life, as it signified the end of my work on BaBar, and also the time when I needed to start settling down at CERN properly, after having spent months planing the trip and trying to balance out my time on the two experiments.
This trip has been a wonderful, once in a lifetime experience. It’s reminded me of why I enjoy pursuing physics in the first place, in spite of the frustrations and the mundane day-to-day work. I love the challenges, the mental acrobatics, the thrill of discovery, sharing that with others, and the opportunities to see the world. It’s true that we have to make sacrifices for physics, we also have great rewards. And so I am, shall we say, Charmed by the experience!