New angles on top quark decay to a charged Higgs Boson

TL;DR

This paper investigates the potential to detect charged Higgs bosons from top quark decays at the LHC by analyzing spin correlations and angular distributions, providing analytic results and Monte Carlo simulations.

Contribution

It offers new analytic expressions for spin analyzing coefficients and explores correlation phenomenology in the Type II 2HDM for top decays involving charged Higgs bosons.

Findings

Analytic results on spin analyzing coefficients for $t o bH^+ o b\tau^+ u_\tau$

Monte Carlo simulations of azimuthal angle distributions sensitive to spin correlations

Distributions accessible in the tau channel for charged Higgs searches

Abstract

Top quarks produced in pairs are predicted to experience spin correlations. Due to the large ttbar statistics expected for the LHC, it should be possible to search for new physics effects in angular variables sensitive to these correlations. We investigate, for a general two-Higgs Doublet Model (2HDM), the charged Higgs boson decay of the top quark through the channel $t\to bH^+\to b\tau^+\nu_\tau$. Analytic results are presented on the spin analyzing coefficients for this decay mode. We then explore in some detail the correlation phenomenology in the Type II 2HDM. Finally we present a hadron-level Monte Carlo analysis, illustrating distributions in azimuthal angles which are sensitive to correlations in the transverse plane. These observables are accessible also in the tau channel, and are therefore particularly interesting for analyzing the $t\to bH^+$ decay.