  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 $\bar{B}\to
D^{(*)}\ell^-\bar\nu$. Our result for the angular distribution is at variance
with some of the results on scalar-vector interference terms in the literature.
We provide numerical estimates for all angular observables based on lattice-QCD
results for the $\Lambda_b \to \Lambda_c$ form factors and account for a recent
measurement of the parity-violating parameter in $\Lambda_c^+\to
\Lambda^0\pi^+$ decays by BESIII. A numerical implementation of our results is
made publicly available as part of the EOS software.
