Abstract

A search for a Higgs boson decaying into a pair of electrons or muons and a photon is described. Higgs boson decays to a Z boson and a photon (H → Zγ → ℓℓγ, ℓ = e or μ), or to two photons, one of which has an internal conversion into a muon pair (H → γ*γ → μμγ) were considered. The analysis is performed using a data set recorded by the CMS experiment at the LHC from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. No significant excess above the background prediction has been found. Limits are set on the cross section for a standard model Higgs boson decaying to opposite-sign electron or muon pairs and a photon. The observed limits on cross section times the corresponding branching fractions vary between 1.4 and 4.0 (6.1 and 11.4) times the standard model cross section for H → γ*γ → μμγ (H → Zγ → ℓℓγ) in the 120–130 GeV mass range of the ℓℓγ system. The H → γ*γ → μμγ and H → Zγ →ℓℓγ analyses are combined for mH =125GeV, obtaining an observed (expected) 95% confidence level upper limit of 3.9 (2.0) times the standard model cross section.

Highlights

  • The CMS detector and triggerA detailed description of the CMS detector can be found in ref. [23]. The central feature of the CMS apparatus is a superconducting solenoid, 13 m in length and 6 m in diameter, which provides an axial magnetic field of 3.8 T

  • A search for a Higgs boson decaying into a pair of electrons or muons and a photon is described

  • Higgs boson decays to a Z boson and a photon (H → Zγ → γ, = e or μ), or to two photons, one of which has an internal conversion into a muon pair (H → γ∗γ → μμγ) were considered

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Summary

The CMS detector and trigger

A detailed description of the CMS detector can be found in ref. [23]. The central feature of the CMS apparatus is a superconducting solenoid, 13 m in length and 6 m in diameter, which provides an axial magnetic field of 3.8 T. A lead-tungstate crystal ECAL and a brass and scintillator hadron calorimeter (HCAL) surround the tracking volume and cover the region |η| < 3. They provide energy measurements of photons, electrons and hadronic jets. The dimuon trigger requires a leading (subleading) muon with pT greater than 17 (8) GeV. The efficiencies of these dilepton triggers as measured in data, for events satisfying the selection criteria, are dependent on the pT and η of the leptons and are measured to be 90–98% and 93–95% for the eeγ and μμγ channels, respectively

Event selection
Signal and background modeling
Systematic uncertainties and results
14 CMS 12 10
25 CMS 20
Findings
Summary
Full Text
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