Scrutinizing the 95–100 GeV di-tau excess in the top associated process
Syuhei Iguro, Teppei Kitahara, Yuji Omura
Abstract
Abstract Recently, the CMS collaboration has reported a di-tau excess with a local significance of 2.6–3.1 $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> where the invariant mass is $$m_{\tau \tau } =95$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>m</mml:mi> <mml:mrow> <mml:mi>τ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>95</mml:mn> </mml:mrow> </mml:math> –100 GeV. This excess can be interpreted as a light scalar boson that couples to the third generation fermions, particularly top and $$\tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>τ</mml:mi> </mml:math> . Based on the simplest model that can account for the CMS di-tau excess, we evaluate experimental sensitivities to the additional light resonance, using the results reported by the ATLAS collaboration. We see that a search for the top-quark associated production of the SM Higgs boson that decays into $$\tau {\bar{\tau }}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>τ</mml:mi> <mml:mover> <mml:mrow> <mml:mi>τ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> </mml:math> sets a strong model-independent limit. We also find that the CP-even scalar interpretation of the light resonance is excluded by the ATLAS results, while the CP-odd interpretation is not.