Search for Rare Events with the CMS Detector and HL-LHC Upgrade Prospects

by Mr Samarendra Nayak (IIT Bhubaneshwar)

Tuesday 30 Sept 2025, 14:30 → 16:30 Asia/Kolkata

D 406 (TIFR, Mumbai)

The angular distributions of the decay B_s⁰→ φμ⁺μ^- are studied using an integrated luminosity of 137.5 fb⁻¹of proton-proton collision data collected with the CMS  (Compact Muon Solenoid) detector at the CERN Large Hadron Collider (LHC) at a  center-of-mass energy of √s = 13 TeV. The CP-averaged angular observable F_L, representing the longitudinal polarization fraction of the K⁺K^- system, and the CP asymmetry observable A₆ are measured as functions of the dimuon invariant mass squared (q²), with the results being preliminary. This decay proceeds via the flavour-changing neutral current (FCNC) transition b → sℓ⁺ℓ^-, which is forbidden at tree level in the Standard Model (SM) and occurs only through higher-order electroweak penguin and box diagrams. Such rare processes provide a powerful probe of potential contributions from physics beyond the SM.  In addition, ongoing instrumentation R&D for the CMS Phase-2 Outer Tracker upgrade for the High-Luminosity LHC (HL-LHC) is presented. This includes noise characterization of multi-module systems of 2S silicon strip sensors using a microTCA-based data acquisition (DAQ) system as part of the service tasks for the upgrade program.