Sizable time-reversal violating effects in bottom baryon decays

Abstract

Abstract We study time-reversal (T) asymmetries in the charmless two-body decays of antitriplet bottom baryons. We find that in B b → B n P with B b = ( Ξ b − $$ {\Xi}_b^{-} $$ , Ξ b 0 $$ {\Xi}_b^0 $$ , Λ b ) and B n (P) a octet baryon (pseudoscalar meson), the positive and negative helicity amplitudes are both sizable, resulting in the large T-violating effects. Particularly, the T-odd parameters, β w , for the color-enhanced channels are expected to be around −40% and 25% in b → s and b → d transitions for the standard model, which can be measured by the experiments at LHCb, respectively. On the other hand, in B b → B n V(γ) with V(γ) a vector meson (photon), the decays are predominated by a single helicity amplitude, and the T violating effects by the correlations among spins are suppressed. We also explore the T violating observables for the Ξ b decays based on the angular distributions.

Keywords

• CP violation
• Heavy Quark Physics