Search for charged Higgs bosons decaying into top and bottom quarks in lepton+jets final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for charged Higgs bosons decaying into top and bottom quarks in proton-proton collisions at 13 TeV, using CMS data, with results interpreted within the generalized two-Higgs-doublet model and an observed excess at 600 GeV.

Contribution

First search for charged Higgs bosons within the g2HDM framework using CMS data at 13 TeV, setting limits on Yukawa couplings and exploring potential signals.

Findings

Observed excess with 2.4 sigma significance at 600 GeV

Excluded $ ho_{tc}$ values above 0.15-0.5 at 95% CL

Set limits on cross section times branching fraction for H$^"+$ decays

Abstract

A search is presented for charged Higgs bosons (H$^\pm$) in proton-proton (pp) collision events via the pp $\to$ (b)H$^\pm$ processes, with H$^\pm$ decaying into top (t) and bottom (b) quarks. The search targets final states with one lepton, missing transverse momentum, and two or more b jets. The analysis is based on data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb$^{-1}$. We search for charged Higgs bosons in the 200 GeV to 1 TeV mass range. The results are interpreted within the generalized two-Higgs-doublet model (g2HDM). This model predicts additional Yukawa couplings of the Higgs bosons to the top quark $\rho_\mathrm{tt}$, the top and charm quark $\rho_\mathrm{tc}$, and the top and up quark $\rho_\mathrm{tu}$. This search focuses on the real components of $\rho_\mathrm{tt}$ and $\rho_\mathrm{tc}$, which are probed up to values of unity. An excess is observed with respect to the standard model expectation with a local significance of 2.4 standard deviations for a signal with an H$^\pm$ boson mass ($m_{\mathrm{H}^\pm}$) of 600 GeV. Limits are derived on the product of the cross section $\sigma$(pp $\to$ (b)H$^\pm$) and branching fraction $\mathcal{B}$(H$^\pm$ $\to$ tb, t $\to$ b$\ell\nu$), where $\ell$ = e, $\mu$. The values of $\rho_\mathrm{tc} \gtrsim$ 0.15$-$0.5 are excluded at 95% confidence level, depending on the $m_{\mathrm{H}^\pm}$ and $\rho_\mathrm{tt}$ assumptions. The results represent the first search for charged Higgs bosons within the g2HDM framework and complement the existing results on additional neutral Higgs bosons.