Abstract

A search is conducted for a low-mass charged Higgs boson produced in a top quark decay and subsequently decaying into a charm and a strange quark. The data sample was recorded in proton-proton collisions at $\sqrt{s} =$ 13 TeV by the CMS experiment at the LHC and corresponds to an integrated luminosity of 35.9 fb$^{-1}$. The search is performed in the process of top quark pair production, where one top quark decays to a bottom quark and a charged Higgs boson, and the other to a bottom quark and a W boson. With the W boson decaying to a charged lepton (electron or muon) and a neutrino, the final state comprises an isolated lepton, missing transverse momentum, and at least four jets, of which two are tagged as b jets. To enhance the search sensitivity, one of the jets originating from the charged Higgs boson is required to satisfy a charm tagging selection. No significant excess beyond standard model predictions is found in the dijet invariant mass distribution. An upper limit in the range 1.68-0.25% is set on the branching fraction of the top quark decay to the charged Higgs boson and bottom quark for a charged Higgs boson mass between 80 and 160 GeV.

Highlights

  • The discovery of the Higgs boson in 2012 by the ATLAS [1] and CMS [2,3] experiments at the CERN LHC has given rise to a wide set of measurements to establish the nature of the discovered particle

  • Collaboration [18] set a 95% confidence level (CL) upper limit on the branching fraction Bðt → HþbÞ of 10%–30% for a charged Higgs boson mass lying in the range 60–150 GeV, assuming that Hþ decays only to cs

  • The inclusive W þ jets and Z=γ þ jets samples are generated at leading order (LO) using MadGraph5_aMC@next-to-leading order (NLO) with up to four partons included in the matrix element calculations

Read more

Summary

INTRODUCTION

The discovery of the Higgs boson in 2012 by the ATLAS [1] and CMS [2,3] experiments at the CERN LHC has given rise to a wide set of measurements to establish the nature of the discovered particle. We are interested in the search for a low-mass (mHþ < mt) charged Higgs boson in the decay channel Hþ → cs (and its charge conjugate), whose branching fraction can range up to 100%, depending on the type of Yukawa coupling The latter is expressed in terms of the parameter tan β 1⁄4 v2=v1, where v1 and v2 are the vacuum expectation values of the two Higgs doublets. Collaboration [18] set a 95% CL upper limit on the branching fraction Bðt → HþbÞ of 10%–30% for a charged Higgs boson mass lying in the range 60–150 GeV, assuming that Hþ decays only to cs. Using 8 TeV data, the ATLAS [20] and CMS [21] Collaborations set an upper limit at 95% CL on the product Bðt → HþbÞBðHþ → τþντÞ of 1.3%–0.23% and 1.2%–0.13%, respectively, for a charged Higgs boson mass in the range 80–160 GeV.

THE CMS DETECTOR
DATA AND SIMULATION
OBJECT RECONSTRUCTION
EVENT SELECTION
DIJET INVARIANT MASS DISTRIBUTION
31 Æ 4 3Æ1 14160 Æ 140
SYSTEMATIC UNCERTAINTIES
VIII. RESULTS
Findings
SUMMARY
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call