T→cg,cγ,cZin the left-right supersymmetric model

Abstract

We analyze top-quark flavor violating decays into a charm quark and a gluon, photon, or $Z$ boson in a supersymmetric model incorporating left-right symmetry. We include loop calculations involving contributions from scalar quarks, gluinos, charginos, and neutralinos. We perform the calculations first assuming the minimal (flavor-diagonal) scalar quark scenario and then allowing for arbitrary mixing between the second and the third generation of scalar quarks, in both the up and the down sectors. In each case we present separately the contributions from gluino, chargino, and neutralino loops and compare their respective strengths. In the flavor-diagonal case, the branching ratio cannot exceed ${10}^{\ensuremath{-}5}$ (${10}^{\ensuremath{-}6}$) for the gluon (photon/$Z$ boson); while for the unconstrained (flavor-nondiagonal) case the same branching ratios can reach almost ${10}^{\ensuremath{-}4}$ for the gluon, ${10}^{\ensuremath{-}6}$ for the photon, and ${10}^{\ensuremath{-}5}$ for the $Z$ boson, all of which are slightly below the expected reach of LHC.