Time-reversal asymmetries in ${\Lambda }_b$ semileptonic decays

Abstract

We study the decays of ${\Lambda }_b\to {\Lambda }_c(\to B_{n}f){\ell }^{-}\overline{\nu }$ with $\ell =e,\mu ,\tau$, where $B_n$ and $f$ are the daughter baryons and the rest of the particles in ${\Lambda }_c$ cascade decays, respectively. In particular, we examine the full angular distributions with polarized ${\Lambda }_b$ and lepton mass effects, in which the time-reversal asymmetries are identified. We concentrate on the decay modes of ${\Lambda }_b\to {\Lambda }_c(\to p{K}^{-}{\pi }^{+}){\ell }^{-}\overline{\nu }$ to demonstrate their experimental feasibility. We show that the observables associated with the time-reversal asymmetries are useful to search for new physics as they vanish in the standard model. Explicitly, we find that they are sensitive to the right-handed current from new physics, and possible to be observed at LHCb.

22 pages, 3 figures, accepted by PRD

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Cited by in corpus (3)

• Anatomy of ${\Lambda }_c^{+}$ semileptonic decays
• Heavy quark symmetry of ${\Lambda }_b^0$ decays in quark models
• Semileptonic decays of doubly charmed baryons with bag model