CP violation in $H^{\pm }t$ production at the LHC

Abstract

We study effects of CP violation in the associated production of a charged Higgs boson and a top quark at the LHC, $pp\to t{H}^{\pm }+X$. We calculate the CP violating asymmetry between the total cross section for $H^{+}$ and $H^{-}$ production at next-to-leading order in the MSSM, and perform a detailed numerical analysis. In the production the asymmetry is of the order of 20%. The asymmetry in the production and any subsequent decay of an on-shell charged Higgs boson is to a good approximation the sum of the asymmetry in the production and the asymmetry in the decay. We consider subsequent decays of $H^{\pm }$ to $tb$, ${\nu }_{\tau }{\tau }^{\pm }$ and $W{h}^0$. In the case with $H^{\pm }\to tb$ decay, mainly due to CP violating box graphs with gluino, the asymmetry can go up to $\sim$ 12%.

Comments: version published in PRD