Search for a charged Higgs boson in $pp$ collisions at $\sqrt{s}$ = 8 TeV

Abstract

A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 $\pm$ 0.5 inverse-femtobarns collected with the CMS detector in proton-proton collisions at $\sqrt{s}$ = 8 TeV. The charged Higgs boson is searched for in top quark decays for m(H+/-) < m(t) - m(b), and in the direct production pp -> t (b) H+/- for m(H+/-) > m(t) - m(b). The H+/- -> tau+/- nu[tau] and H+/- -> t b decay modes in the final states tau[h]+jets, mu tau[h], l+jets, and ll' (l = e, mu) are considered in the search. No signal is observed and 95\% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction $\mathrm{\mathcal{B}}\left(\mathrm{t}\to {\mathrm{H}}^{\pm}\mathrm{b}\right)\mathrm{\mathcal{B}}\left({\mathrm{H}}^{\pm}\to {\tau}^{\pm }{\nu}_{\tau}\right)=1.2-0.15\%$ is obtained in the mass range m(H+/-) = 80-160 GeV, while the upper limit on the cross section times branching fraction $\sigma \left(\mathrm{pp}\to \mathrm{t}\left(\mathrm{b}\right){\mathrm{H}}^{\pm}\right)\mathrm{\mathcal{B}}\left({\mathrm{H}}^{\pm}\to\ {\tau}^{\pm }{\nu}_{\tau}\right)=0.38-0.025$ pb is set in the mass range m(H+/-) = 180-600 GeV. Here, cross section sigma( pp -> t (b) H+/- ) stands for the sum $\sigma \left(\mathrm{pp}\to \overline{\mathrm{t}}\left(\mathrm{b}\right){\mathrm{H}}^{+}\right)+\sigma \left(\mathrm{pp}\to \mathrm{t}\left(\overline{\mathrm{b}}\right){\mathrm{H}}^{-}\right)$. Assuming $\mathrm{\mathcal{B}}\left({\mathrm{H}}^{\pm}\to \mathrm{t}\mathrm{b}\right)=1$, an upper limit on sigma ( pp -> t (b) H+/- ) of 2.0-0.13 pb is set for m(H+/-) = 180-600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m(H+/-)-tan $\beta$ parameter space in different MSSM benchmark scenarios.