Performance of the H -> ZZ* -> 4 mu analysis with the CMS Phase-2 muon detector upgrade

A study of the performance of the Standard Model H(125 GeV) -> ZZ* -> 4 mu analysis with the upgraded CMS muon detector for the high luminosity operation (up to 7.5 x 10^{34} cm^{-2}s^{-1}) at the Large Hadron Collider (HL-LHC) has been carried out. The CMS Phase-2 muon detector upgrade, which will take place from 2024 to 2026, is crucial to efficiently exploit the data that will be collected at the HL-LHC, under very challenging experimental conditions, such as large number of overlapping collisions per event, up to 200 (referred to as pile-up). The H -> ZZ* -> 4 mu analysis essentially relies on the muon system to detect four muons in the final state; it therefore represents an important benchmark for the proposed muon detector upgrade, in particular the extension in pseudorapidity of the muon detector from |eta| < 2.4 to |eta| < 2.8 by introducing the ME0 (Muon Endcap 0) subdetector. The results presented here are obtained using simulated proton-proton collision events at sqrt{s} = 14 TeV with the full simulation of the upgraded CMS detector. The signal and background events are simulated with an average pile-up of 200. The analysis is performed assuming an integrated luminosity of 3000 fb^{-1} (expected in almost ten years of the HL-LHC operation) and follows the analysis of the 2016 data (Run-2). It is found that the signal selection efficiency remains immune to the high pile-up conditions and increases by 17% with the acceptance extension of the muon system.