ChrisBerman iSURF Letter

Dear iSURF Committee,

I am writing to strongly support Chris Berman's application for a CMU iSURF position. Chris is proposing to build on the work he started with his SURF grant this past summer. The case to continue this work internationally is natural and compelling. The experiment is located at CERN in Geneva, Switzerland, and many of the relevant experts are based at the lab full time. As detailed below, these experts are precisely what is needed to take Chris's work to the next level. This fellowship would be of significant benefit not only to Chris but also to my group at CMU and the CMS collaboration as a whole.

Chris came to me last semester highly recommended by Tudor Manole, a statistics graduate student with whom I collaborate on research. Chris spent a semester doing background reading and obtaining the necessary credentials to collaborate on the CMS experiment at the CERN Large Hadron Collider (LHC).

Chris then worked during the summer on a project that is both important and timely. I study Higgs boson production at colliders. One of the current missing pieces in our understanding of the Higgs boson is how (or indeed if) it interacts with strange quarks. This interaction is predicted by our best theory—the Standard Model of particle physics—but has yet to be observed. Observing this interaction is challenging, as identifying strange quarks in our detectors is inherently difficult. The detectors at the LHC are not designed to distinguish strange quarks from other more commonly produced particles. However, we are currently in the process of designing next-generation detectors for an electron-positron collider. This would be the ideal environment to detect strange quarks, and we now have the opportunity to design a detector optimized for this purpose.

The goal of Chris’s work is to understand how the trade-offs in future detector designs would affect our ability to identify strange quarks. During his SURF fellowship, he analyzed the best-case scenario of a perfect detector. This work established a well-understood baseline against which we can cross-check future results. Chris went beyond previous studies by using more advanced machine learning tools, specifically attention-based networks. This work allowed Chris to make connections with other scientists and plan for future collaboration at CERN.

There are two obvious directions for Chris's work. The first is to emulate the type of imperfections expected in the data from a realistic detector. Implementing this will allow Chris to understand how imperfections degrade bottom-line performance. These studies will require him to understand the details of the detector response. Almost all of the relevant experts in this area are based at CERN or will be there during the summer. In particular, Chris has been working with CERN scientist Dr. Johannes Erdmann, a leading expert in this area. The ambitious goal of this work is to create a tool to optimize next-generation detectors for measuring this important signal.

The second direction is to implement Chris's tool in the existing CMS detector. The much noisier proton collisions of the LHC present a more challenging environment for identifying strange quarks. However, this will allow Chris to calibrate his model in situ with real data and let us see how far we can push the existing detector to do something it was not originally designed for.

In summary, I strongly support this application for an iSURF award. This work is an important extension of the work Chris conducted in the SURF program, and it is crucial for him to do so internationally at CERN. This work will be done in collaboration with a research group at CERN, which I have convened. Of course, I will continue to guide, mentor, and assist Chris as needed.

Please feel free to contact me to discuss Chris’s project further.

John Alison