Enhanced three-body decay of the charged Higgs boson

Abstract

If the charged Higgs boson H⁺ exists with m_H+<m_t+m_b, the conventional expectation is that it will decay dominantly into cs̅ and τ⁺ν_τ. However, the three-body decay mode H⁺ → W⁺bb̅ is also present and we show that it becomes very important in the low tanβ region for m_H+≳140 GeV. We then explore its phenomenological implications for the charged-Higgs-boson search in top-quark decay.