The experimental particle physics group at Cornell University is involved with research and upgrades at the LHC with the CMS detector.
An experimental particle physics group from the Cornell Laboratory of Accelerator-based ScienceS and Education (CLASSE) is collaborating with groups from around the world, to help build and operate the Compact Muon Solenoid (CMS) detector, to analyse the data produced by it. The team, currently consisting of five faculty members, approximately ten graduate students, five postdoctoral researchers, and several undergraduate students, is responsible for operating and maintaining aspects of the pixel detector and its future upgrades, and for certain parts of the CMS software. Data analysis efforts by the group include studies of the Higgs boson, top quark measurements, and searches for long beyond standard model particles.
The Large Hadron Collider and the CMS experiment
The Large Hadron Collider (LHC) at CERN is the highest energy particle collider in the world. It collides proton beams with a centre of mass energy of 13.6 TeV. This energy is about 14,500 times the rest energy of a proton. The particles produced in the proton-proton collisions are studied by the CMS detector. CMS is a multi-purpose detector capable of reconstructing a large range of particles to allow studies of, e.g., Higgs bosons, top quarks, and the W and Z bosons.
The Higgs boson
The most important result from the LHC physics programme was the observation of the Higgs boson by the CMS and ATLAS experiments in 2012. In the Standard Model of particle physics, the Higgs boson is responsible for generating the mass of particles. This gives the Higgs the unique property of having a coupling to other particles proportional to the mass of the particle. We can test the Standard Model that Higgs is responsible for by measuring the particle’s coupling to the Higgs boson and comparing this to the particle’s mass.
The Higgs boson was the last particle in the Standard Model to be discovered and is one of the least well-studied fundamental particles. One of the most important areas of research in particle physics is the study of the Higgs boson properties. At Cornell, we are participating in CMS data analysis to explore the properties of the Higgs boson to constrain any deviations from the Standard Model.
However, to achieve this, a very large sample of Higgs bosons is needed for analysis. CERN is upgrading the LHC to the High-Luminosity LHC, which will produce more Higgs bosons per year, causing more proton-proton collisions. This will allow more detailed studies of the Higgs boson, and other particles, than has been possible to date.
Detector upgrades for CMS
With the increased proton-proton collision rate from the HL-LHC, the CMS detector needs to be upgraded to handle the larger data rate and survive in the intense radiation environment.
At CLASSE, we are leading the US National Science Foundation’s effort to upgrade the CMS detector. This project involves about 30 US universities and will deliver key upgrades to the CMS detector for the HL-LHC operations, scheduled to start in 2029. At Cornell, we are involved in the construction of a new pixel detector for the forward region and a novel track trigger.
- Physics associated with the Higgs boson and beyond Standard Model searches;
- Instrumentation for particle detectors; and
- Charged particle tracking.