  We derive the $\Lambda_b \to \Lambda_c$ form factors for the Standard Model
and beyond at second order in Heavy Quark Effective Theory (HQET), applying the
recently-proposed Residual Chiral Expansion (RCE) to reduce the set of unknown
subsubleading hadronic functions to a single, highly-constrained function, that
is fully determined by hadron mass parameters at zero recoil. We fit a form
factor parametrization based on these results to all available Lattice QCD
(LQCD) predictions and experimental data. We find that the constrained and
predictive structure of the form factors under the RCE is in excellent
agreement with LQCD predictions and experimental data, as well as prior
HQET-based fits.
