29 June 2026 to 3 July 2026
Ray Dolby Centre
Europe/London timezone

Searches for long-lived particles decaying in the CMS muon detector system

3 Jul 2026, 10:15
15m
Ray Dolby Centre

Ray Dolby Centre

J J Thomson Avenue, Cambridge, CB3 0US, UK
Talk 12'

Speaker

Karim El Morabit (Hamburg University (DE))

Description

Many extensions of the Standard Model predict new long-lived particles (LLPS) with a wide range of possible proper lifetimes, masses and decay modes.

This talk presents recent results for searches for long-lived particles decaying inside the CMS muon detector system. The focus will be on the most recent results obtained with proton-proton collisions recorded during LHC Run 3, corresponding to an integrated luminosity of 170 1/fb. The CMS muon detector system consists of gaseous detectors interleaved with layers of steel of the magnetic flux-return yoke. Long-lived particles decaying within the steel can induce electromagnetic and hadronic showers which can be reconstructed as high multiplicity hit clusters, effectively interpreting the muon detector system as a sampling calorimeter. This so-called muon detector shower (MDS) signature is therefore sensitive to various LLP decay modes, including decays to hadrons and taus. The MDS are furthermore only sensitive to the energies of the LLPs, not their mass, allowing searches to reach high sensitivity independent of the LLP mass. In addition, the detector material and steel in front of and in between the muon detectors provides effective shielding against many sources of background that would affect searches in the inner parts of the CMS detector. Dedicated triggers have been developed and successfully deployed to record events with this unique MDS signature during LHC Run 3. Analyses by the CMS Collaboration using the MDS signature include not only searches for LLPs over a wide range of masses, but also searches for heavy-neutral leptons.

Submitted on behalf of ... Submitted centrally on behalf of the Collaboration

Authors

Hongbo Liao (Chinese Academy of Sciences (CN)) Karim El Morabit (Hamburg University (DE))

Presentation materials