Cloistered baryogenesis

Abstract

The cosmological matter-antimatter asymmetry can arise from the baryon number\nconserving CP asymmetry in two body decays of heavy particles, when the two\nfinal states carry equal and opposite baryon number, and one couples directly\nor indirectly to electroweak sphalerons so that its baryon asymmetry gets\npartly reprocessed into a lepton asymmetry, while the other remains chemically\ndecoupled from the thermal bath with its baryon content frozen. After sphaleron\nswitchoff the decay of the decoupled particles inject in the thermal plasma an\nunbalanced baryon asymmetry, giving rise to baryogenesis. We highlight the\nfeatures of this mechanism in a type-I seesaw model extended by adding a new\ncolored scalar coupled to the heavy Majorana neutrinos. If the colored scalar\nhas an O(TeV) mass, it would leave at the LHC a characteristic signature\nthroughout all layers of the detectors.\n