| Thesis | |
| Report number | CERN-THESIS-2024-221 ; CMS-TS-2024-013 |
| Title | Exploring Long-Lived Particles decaying into Displaced Dimuons with the CMS experiment |
| Author(s) | Sonawane, Mangesh (Vienna, OAW) |
| Publication | 2024 - 200. |
| Thesis note | PhD : TU Vienna : 2024 |
| Thesis supervisor(s) | Schöfbeck, Robert ; Escalante del Valle, Alberto |
| Note | Presented 18 Oct 2024 |
| Subject category | Particle Physics - Experiment |
| Accelerator/Facility, Experiment | CERN LHC ; CMS |
| Abstract | Many well-motivated theories beyond the Standard Model of particle physics propose the existence of exotic-long lived particles. These long-lived particles could be produced in high-energy proton-proton collisions and go on to decay into known particles, which could be detected a macroscopic distance away from the proton-proton collision point. This thesis presents an inclusive search for long-lived exotic particles decaying to a pair of muons. The experimental signature consists of two oppositely charged muons originating from a common secondary vertex, displaced from the proton-proton interaction point by distances ranging between several hundred micrometers to several meters. The search uses data collected by the CMS experiment at the CERN LHC in proton-proton collisions at $\sqrt{s}=13.6$~TeV in 2022, corresponding to an integrated luminosity of 36.6~$\text{fb}^{-1}$, using new trigger strategies designed to maximize sensitivity to events bearing such a signature. These trigger strategies employ new and existing reconstruction algorithms innovatively, benefiting from the higher resolution of the tracker as well as the extensive coverage of the muon system, to achieve lower trigger thresholds while simultaneously suppressing prompt backgrounds. The results of the search are interpreted in the framework of the hidden Abelian Higgs model, in which the Higgs boson decays to a pair of long-lived dark photons, which in turn decay into a pair of displaced muons, and of an R-parity violating supersymmetry model, in which long-lived neutralinos decay to a pair of muons and a neutrino. No statistically significant excess was observed over the predicted Standard Model background hypothesis, and limits were set on the model parameters. The results show substantial improvements with respect to a previous analysis performed using data taken at $\sqrt{s}=13$~TeV, especially at low masses and long lifetimes, which are mainly driven by the improved triggers and a refined analysis strategy. |
Corresponding record in: INSPIRE
Email contact: mangesh.sonawane@cern.ch
Záznam vytvorený 2024-11-05, zmenený 2024-12-18