Search for a massless dark photon in Lambda(+)(c) -> p gamma' decay

Abstract

The flavor changing neutral current (FCNC) transitionsof the charmed baryonΛþcare of great interest since theycan provide indications for physics beyond the StandardModel (SM). In the framework of the SM, FCNC tran-sitions are strongly suppressed by the Glashow, Iliopoulosand Maiani mechanism[1]in the charm sector. The SMpredictions for the branching fractions (BFs) of FCNCdecays in the charm sector are less than10−9[2]. Theminimal supersymmetric SM with R-parity violation[3]and the two-Higgs-doublet model[4]predict the BFs of thesame FCNC decays to be two to three orders of magnitudelarger