Search for charged Higgs bosons in top quark decays

TL;DR

This paper searches for charged Higgs bosons in top quark decays using collider data, setting limits on their properties and excluding certain parameter regions in supersymmetric models.

Contribution

It introduces a comprehensive search for charged Higgs bosons across multiple decay channels in top quark events, with new limits on branching ratios and parameter space.

Findings

Excluded regions in charged Higgs mass and tan beta parameter space.

Set upper limits on the branching ratio B(t→H+ b).

Used two analysis methods to improve robustness.

Abstract

We present a search for charged Higgs bosons in top quark decays. We analyze the \eplus, \muplus, $ee$, $e\mu$, $\mu\mu$, \etau and \mutau final states from top quark pair production events, using data from about 1${\text{fb}}^{-1}$ of integrated luminosity recorded by the \dzero experiment at the Fermilab Tevatron Collider. We consider different scenarios of possible charged Higgs boson decays, one where the charged Higgs boson decays purely hadronically into a charm and a strange quark, another where it decays into a $\tau$ lepton and a $\tau$ neutrino and a third one where both decays appear. We extract limits on the branching ratio $B(t\to H^+ b)$ for all these models. We use two methods, one where the $t\bar{t}$ production cross section is fixed, and one where the cross section is fitted simultaneously with $B(t\to H^+b)$. Based on the extracted limits, we exclude regions in the charged Higgs boson mass and $\tan \beta$ parameter space for different scenarios of the minimal supersymmetric standard model.