Searches for heavy Higgs bosons in two-Higgs-doublet models and for t to ch decay using multilepton and diphoton final states in pp collisions at 8 TeV

TL;DR

This paper reports on searches for heavy Higgs bosons and rare top quark decays in proton-proton collisions at 8 TeV, setting upper limits on production cross sections and branching fractions in various decay channels.

Contribution

It provides the first experimental limits on heavy Higgs bosons decaying to hh and Zh, and on the rare t to ch decay, within the 2HDM framework using CMS data.

Findings

Set 95% CL upper limits of ~7 pb for H to hh and 2 pb for A to Zh.

Placed a 95% CL upper limit of 0.56% on B(t to ch).

Constrained 2HDM parameters based on observed data.

Abstract

Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of sqrt(s) = 8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. The decays H to hh and A to Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% CL cross section upper limits of approximately 7 pb on sigma times B for H to hh and 2 pb for A to Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t to ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% CL upper limit of 0.56% on B(t to ch).