Sizable time-reversal violating effects in bottom baryon decays

We study time-reversal (T) asymmetries in the charmless two-body decays of antitriplet bottom baryons. We find that in B-b -> BnP with B-b = (Xi(-)(b), Xi(b)0, Lambda(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, beta(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 -> BnV(gamma) with V(gamma) 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 Xi(b) decays based on the angular distributions.

Automated summary

We study T-violating effects in the charmless two-body decays of antitriplet bottom baryons. The T-odd parameters can be measured by experiments and the effects are either significant or suppressed depending on the decays.