CP-violating Higgs boson mixing in chargino production at the muon collider

TL;DR

This paper investigates CP-violating effects in chargino production at a muon collider, focusing on Higgs sector mixing near heavy Higgs resonances, and demonstrates potential for observing sizable CP asymmetries.

Contribution

It provides a detailed numerical analysis of CP violation in chargino production, highlighting the impact of Higgs mixing and resonance effects in the MSSM at muon colliders.

Findings

Sizable CP asymmetries are predicted and could be measured at future muon colliders.

Higgs sector mixing significantly alters the mass spectrum and CP-violating observables.

The process is especially sensitive at intermediate aneta values, revealing Higgs-fermion interactions.

Abstract

We study the pair-production of charginos in the CP-violating Minimal Supersymmetric Standard Model at center-of-mass energies around the heavy neutral Higgs boson resonances. If these resonances are nearly degenerate, as it can happen in the Higgs decoupling limit, radiatively induced scalar-pseudoscalar transitions can be strongly enhanced. The resulting mixing in the Higgs sector leads to large CP-violating effects, and a change of their mass spectrum. For longitudinally polarized muon beams, we analyze CP asymmetries which are sensitive to the interference of the two heavy neutral Higgs bosons. We present a detailed numerical analysis of the cross sections, chargino branching ratios, and the CP observables. We obtain sizable CP-asymmetries, which would be accessible in future measurements at a muon collider. Especially for intermediate values of the parameter \tan\beta, where the largest branching ratios of Higgs bosons into charginos are expected, this process allows to analyze the Higgs sector properties and its interaction to supersymmetric fermions.