CP-violating asymmetry in chargino decay into neutralino and W boson

Abstract

In the MSSM with complex parameters, loop corrections to ${\text{cha}}_i^{\pm }\to {\text{neu}}_j^0{W}^{\pm }$ lead to a CP violating asymmetry $\text{ACP}=(\Gamma ({\text{cha}}_i^{+}\to {\text{neu}}_j^0{W}^{+})-\Gamma ({\text{cha}}_i^{-}\to {\text{neu}}_j^0{W}^{-}))/(\Gamma ({\text{cha}}_i^{+}\to {\text{neu}}_j^0{W}^{+})+\Gamma ({\text{cha}}_i^{-}\to {\text{neu}}_j^0{W}^{-}))$. We calculate this asymmetry at full one-loop level. We perform a detailed numerical analysis for ${\text{cha}}_1^{\pm }\to {\text{neu}}_1^0{W}^{\pm }$ and ${\text{cha}}_2^{\pm }\to {\text{neu}}_1^0{W}^{\pm }$ analyzing the dependence on the parameters and phases involved. Asymmetries of several percent are obtained. We also discuss the feasability of measuring these asymmtries at LHC.

Comments: 14 pages, 6 figures, version to be published in PLB