“In particle physics, you never do the same work everyday”

A 25-year-old from Italy, Marco Cipriani is a PhD student at the Sapienza University of Rome and the Italian National Institute for Nuclear Physics (INFN) in Rome. He has been a member of CMS since his master’s studies, although he decided to study particle physics itself just before getting into university.

“In high school, I was a little undecided between physics and chemistry; I knew I wanted to undertake scientific studies for sure but I was not sure about which sector of science. But at the end of high school, I attended some courses and lectures that were held at the Italian national physics laboratory in Frascati near Rome, and this was the experience that made me decide, OK, now I’m sure I want to do particle physics.”

In fact, it was more than just the courses that proved to be an inspiration. Marco’s decision to study particle physics was driven by the discovery of the Higgs boson in 2012 by CMS and ATLAS. It made him want to join an LHC collaboration to conduct research at the world’s most powerful particle accelerator.

“When I was to start my master’s thesis during the fifth year of my university studies, I contacted a professor who I already knew, and who was (and still is) a part of CMS, to ask for a topic to work on. I went to him to ask what he was involved in, and he told me that one of the topics he was following was the search for dark matter at CMS, which was something I found really exciting. So I started my master’s degree thesis with his supervision. CMS has a wide programme focused on the search for dark matter, and I was working on a specific channel called the mono-jet channel, where basically you search for the production of dark-matter particles in association with one or more particle jets.”

The project proved to be a valuable learning experience for Marco, who worked on the analysis with researchers from the US, Italy and Belgium. He is now in the second year of his PhD studies and has switched topics, moving to measuring the properties of the W boson with CMS data.

“The precise measurement of the mass of the W boson was already provided by LEP and the Tevatron. At the LHC, a measurement was recently provided by ATLAS. But this measurement was not made by CMS previously. There were some preparatory studies, but a real measurement is still missing. CMS has in the past years focused more on the feasibility studies based on the measurement of the Z boson’s mass in the same way as you would do with the W. There are some difficult aspects that we have to work on to carry out the measurement, and for now we are still at the beginning. But I think we will manage to provide a good measurement, I am sure about that!”

Marco works on the W boson’s mass measurement with scientists from Italian groups at Rome, Pavia and Pisa as well as with researchers based at CERN or belonging to institutes from the US. And although he doesn’t know everyone in the analysis group yet, he looks forward to getting better acquainted with them. But working in such an international environment comes with its challenges as well.

“I found it very amusing that when you have to interact with other people who are not from your country, first of all you have to somehow overcome the possible problem of language. In principle it is not a problem, and it actually helps! Since it’s not your own language, you have to find the best way to interact with other people by being precise and focusing on the exact points you want to convey. Of course from the social point-of-view, I must say it’s very nice because you can have many discussions that are not just about work. During the free time you can also get to know each other and it’s very helpful because to do a good job together it’s important to build social relations.”

According to Marco, working in particle physics never gets boring: you are often required to change the focus of your work and this can be very rewarding.

“When I was searching for dark matter I was first involved in the estimation of the background. Then I, of course, expanded to the whole analysis. The most interesting part of this job is you move from one topic to another. You can learn a lot of things about all the different aspects of building a physics analysis and what’s even more important is you can very often collaborate with other people: you can share knowledge, thoughts, opinions, doubts, which is very helpful. Sometimes it’s difficult when you’re not located at CERN because many people are there, and talking over video calls is not the same, so I also enjoy very much the opportunity of coming to CERN, having the possibility to interact in person with all these people. You can have an always-moving experience in particle physics and you never do the same work everyday.”

And of course Marco is sure that anyone interested in pursuing a career in particle physics should dive right in.

“I would suggest you pursue particle physics first of all because it is a very exciting field. So for sure it would not be a bad choice! And you will have a lot to learn, so, in case one day you decide to change your career, you would’ve accumulated a lot of knowledge, both scientific knowledge and also knowledge about how to work within a group. As in my case, I suggest you follow some specific lectures because that was the experience that made me decide what I want to do – at least for the moment! – for the rest of my life. We are on the frontiers of science and no-one will regret trying the experience. On the other hand, a regret would be not trying it, possibly. So, join the LHC and join CMS!”

As young as CMS…

A handful of CMS members were born around the time the CMS itself came into being. They are as old (or as young!) as the collaboration they are now a part of. To give you a unique point of view of what it means to scientists in the early stages of their careers to be involved in such a long-standing enterprise, we interviewed a few of them. Find out more about what brought them to particle physics, what they work on in CMS and what they look forward to in the years to come.

About

In October 1992, a ‘Letter of Intent’ was submitted to the LHC Experiments Committee (LHCC), offically marking the formation of the CMS Collaboration. This website commemorates the 25th anniversary of CMS, celebrated in 2017.