Angular Analysis of \boldmath $\Lambda_b\to \Lambda_c (\to \Lambda \pi)\ell\bar\nu$

Understand

We revisit the decay $\Lambda_b^0\to \Lambda_c^+ \ell^-\bar\nu$ ($\ell = e,\mu,\tau$) with a subsequent two-body decay $\Lambda_c^+ \to \Lambda^0 \pi^+$ in the Standard Model and in generic New Physics models.

• The decay's joint four-differential angular distribution can be expressed in terms of ten angular observables, assuming negligible polarization of the initial $\Lambda_b$ state.
• We present compact analytical results for all angular observables, which enables us to discuss their possible New Physics reach.
• We find that the decay at hand probes more and complementary independent combinations of Wilson coefficients compared to its mesonic counter parts $\bar{B}\to D^{(*)}\ell^-\bar\nu$.