Search for SUEPs produced in association with a vector boson at the LHC with CMS Run II data
OA Version
Citation
Abstract
The Standard Model (SM) of particle physics describes known fundamental particles and their interactions. However, it fails to account for the evidence of dark matter (DM). This thesis presents a search for a beyond-the-Standard-Model (BSM) signature that could connect the SM to DM: soft unclustered energy patterns (SUEPs). These models predict that at sufficiently high energies, a scalar mediator couples to a dark quantum chromodynamics (QCD) sector whose particles eventually decay back into the SM, producing a soft, isotropic spray of charged particles - the SUEP signature. One of the Large Hadron Collider's (LHC) primary goals is to probe high energy collisions for signatures of DM. Using data collected during Run II of the LHC's 13 TeV proton–proton collisions with the Compact Muon Solenoid (CMS) detector, corresponding to an integrated luminosity of 137.8 fb^-1, a search for SUEPs is presented. Final states with a high multiplicity of low-momentum tracks and leptonic activity compatible with a W or Z boson decay are explored for the first time. The background estimation strategy employs the data-driven extended ABCD method. The results show no significant excess over the SM expectation, and are interpreted as upper limits (ULs) set on the branching fraction of Higgs boson decays to SUEPs.
Description
2026
License
Attribution 4.0 International