Fresh faces at CMS

Summer is a time for energy and vitality, and one glance at the lunchtime cafeteria confirms that this is true for physics as well. Summer is when interns arrive at Fermilab and you see young faces everywhere.

Fermilab runs several vibrant programs aimed at educating students of all ages in all of our myriad technical endeavors, be they scientific, engineering or computational. All departments participate in these programs, but the CMS Department was especially luckily this summer. We were able to attract over a dozen exceptional young interns who participated in a broad swath of CMS activities, spanning analysis, detector upgrades and computer infrastructure.

Alex Bisnath of the University of Chicago worked with Fermilab Wilson fellow Nhan Tran on Higgs physics. He worked on a particularly thorny problem, which was to identify charm quarks. He trained neural networks to isolate the difficult signal where Higgs and Z bosons decay into charm quarks.

Tran said, “Alex arrived with little CMS experience but was able to make meaningful contributions to the team. He streamlined the machine learning pipeline for the development of novel neural networks and has started to develop models which discriminate between double charm quark versus charm-plus-strange quark boson decays. His enthusiasm and diligence have made him a pleasure to collaborate with this summer.”

Fermilab research associate Mia Liu also worked with an intern on Higgs boson analysis techniques. Austin Grenert is a student at nearby Elgin Community College, and he spent his summer performing a sensitivity study to understand how well CMS could investigate how Higgs bosons interact with Higgs bosons. He did this using CMS simulated data that contained two W bosons and a Higgs boson.

This summer, CMS attracted over a dozen exceptional young interns who participated in a broad swath of CMS activities, spanning analysis, detector upgrades and computer infrastructure. Photo: Gabriele Benelli

Alex enjoyed his summer, saying “It was certainly a privilege to work among such great individuals in an atmosphere that encourages curiosity. This experience broadened my academic horizons, as I developed an understanding of concepts that were previously unfamiliar. In addition to this personal growth, I was able to make a contribution in the scientific community, which to me is very valuable.”

Students did not only work on data analysis. Others experienced the hands-on side of making a detector like CMS work. Fermilab research associate Fabio Ravera and applications physicist Lorenzo Uplegger mentored two interns. Pietro Tricarico of the University of Camerino worked on the DAQ software for the CMS Phase II tracker and, in particular, on the CMS binary chip calibration procedures. This work is fundamental in integrating the control and readout of 2S modules into the OtSDAQ framework developed by the Fermilab Computing Division. Their second intern, Michele Mormile of University of Naples Federico II analyzed data collected at the Fermilab Test Beam Facility on a 2S minimodule prototype before and after it was irradiated with a high dose of neutrons.

Fermilab scientists Zoltan Gecse and Ron Lipton and research associate Maral Alyari supervised three students: Scott Israel of the University of Massachusetts, Amherst, Peter Camporeale of the University of Chicago, and Michael Campanella of Florida State University. These students joined the large Fermilab effort to design and build silicon sensors and modules for the CMS high-granularity calorimeter upgrade. This effort is centered at the Fermilab Silicon Detector Facility, and the students studied the performance of silicon sensors.

“There are many performance properties we need to understand,” Gecse said. “These students investigated such things as leakage current, noise properties and the detailed chip structures both before and after irradiation. Their results will help inform CMS as we make detailed decisions about the design parameters and technologies used by the vendors.”

Interns are often college students, but not all of them. For instance, my own intern was a high school student from nearby Stevenson High School. Sam Wang analyzed test beam data that studied the performance of plastic scintillator tiles that will be used in the CMS end cap high-granularity calorimeter upgrade. He succeeded so well that I also assigned him a side project to work on doing timing measurements for the proposed MATHUSLA detector, which hopes to find long-lived particles at a facility located on the surface above the CMS or ATLAS detector caverns. He was remarkably quick to pick up on the necessary analysis techniques. His experience this summer strengthened his interest in combining computers and physics to do particle physics research.

The range of skills necessary to successfully execute a modern particle physics experiment are quite broad, and we had interns involved in all facets. Fermilab staff members Eric Vaandering and Natalia Ratnikova mentored University of Pisa student Fabio Condomitti, who worked on the Rucio project, which is the next-generation CMS data management software.

Vaandering said, “Large-scale data movement is an integral component of any modern physics experiment, and students like Fabio are helping us prepare our data transfers for LHC Run 3 and beyond.”

Internships obviously benefit the students, but they also benefit the field. Of course, we are able to use their skills and effort to advance the crucial projects that Fermilab has undertaken, but the field benefits more than that. These students are young now, but in a few short decades they will be leaders of the field of particle physics. Like seed corn sprinkled on the ground in the spring, they will grow into the crop of tomorrow. As has long been true, the Fermilab intern program will have played an important role in providing the next generation of researchers the skills they need to ensure that the future of particle physics research is a success.

Don Lincoln is a Fermilab scientist on the CMS experiment.