LBNL ATLAS Masterclass

The ATLAS Masterclass is conducted every April at the Lawrence Berkeley National Laboratory and is a great place to get introduced to the impossible world of particle physics. Participating in the program gave me a great opportunity to meet many PhD and postdoctoral researchers at the lab who explained in detail what they work on. After arriving, we were given an introductory lecture to particle physics and the standard model; here is where we truly understood the depth of our own ignorance of many of the ways in which these subatomic particles interacted. The main activity of the day was to analyze data from the Large Hadron Collider–a particle accelerator at CERN (Conseil Européean pour la Recherche Nucléaire) in Geneva, Switzerland. It is a fitting name given that it is the largest particle accelerator and collides protons together, which are part of the hadron group. Specifically, we were to analyze a dataset from one of the four detectors located around the LHC: the ATLAS detector. So what are we analyzing exactly? Well, when the two protons collide, they form one of a variety of particles that decay into smaller particles immediately and we look for what type of particle was formed by the collision to try to understand it better. To do that, we looked at the different tracks of energy that various decay particles left in the detector after the collision; using mathematical calculations, the mass and other properties of the original particle can be determined. In the program itself, each person was given fifty different collisions to analyze and label the decay particles and the computer does calculations to see if there is a particle at the original location and what that particle could be. In reality, this is all done by computer algorithms but we performed a forceful, slower approach to the problem to learn the concepts as we moved along.

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Once we spent a few hours analyzing each of our data, we had a break for lunch and reconvened with all of the combined data. Using the masses in which we found particles, we identified them with existing particles and noticed an anomaly at approximately 125 GeV–125 giga-electron Volts, a unit of mass. This showed us that a particle existed at this mass index that turned out to be the Higgs boson; the experiment we performed replicated the exact procedure that actual LHC scientists took to find this particle and fundamentally changed our understanding of the universe in 2012.

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After our conference with other students across the world participating in the masterclass and sharing our similar data, we got to take a tour of the particle accelerator–more specifically, cyclotron–at the Lawrence Berkeley National Laboratory campus. We learned a lot about what the particle accelerator does, how it works, and what sorts of experiments are ongoing within it. This specific particle accelerator is a cyclotron, which means it speeds up the particles in a smaller circular accelerator before launching them into the main ring. The Berkeley accelerator uses electrons that it sends out in bunches to collide with each other and conduct experiments. One such experiment is imaging proteins, and over five percent of the world’s imaged proteins come from the Berkeley laboratory–that’s over 8,000 proteins! 

Overall, it was a great experience to be introduced to the field of particle physics, not only learning the theoretical concepts but also applying them to data and analyzing that data, as well as being exposed to an in-depth tour of the instruments and labs.