First Measurement of the muon p_T-dependent Bending Angle between the GEM and CSC subdetectors using Run 3 data

The Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) serves various purposes in studies ranging from precision measurements of known Standard Model (SM) physics to testing new hypotheses beyond the SM. At the high luminosity LHC (HL-LHC), achieving acceptable first level trigger rates for muons with reasonable transverse momentum thresholds is not viable with the original detector, due to high occupancy in the endcap region. In order to retain the current standalone muon trigger capability in this endcap region during the HL-LHC, the Gas Electron Multiplier (GEM) subdetector system was designed. It was installed in the first muon station of the endcap region during the second long shutdown (2019-2021). Performance improvements in the standalone muon trigger are mainly expected from the p_T-dependent bending angle measured between the GEM and Cathode Strip Chambers (CSC) detectors. In this presentation, we show the impact of GEM alignment with a muon-track on this bending angle measurement. Corrections are for the GEM position relative to the CSC. The alignment algorithm was previously tested using cosmic ray muons and 2021 pilot-beam proton-proton collision data. We are now reporting the early muon track bending angle results with Run-3 data.