A lattice QCD determination of the $Lambda_c to N$ vector, axial vector, and tensor form factors is reported. The calculation was performed with $2+1$ flavors of domain wall fermions at lattice spacings of $aapprox 0.11:{rm fm},:0.085:{rm fm}$ and pion masses in the range $230:{rm MeV} lesssim m_pi lesssim 350$ MeV. The form factors are extrapolated to the continuum limit and the physical pion mass using modified $z$ expansions. The rates of the charged-current decays $Lambda_c to n, e^+ u_e$ and $Lambda_c to n, mu^+ u_mu$ are predicted to be $left( 0.405 pm 0.016_{,rm stat} pm 0.020_{,rm syst} right)|V_{cd}|^2 :{rm ps}^{-1}$ and $left( 0.396 pm 0.016_{,rm stat} pm 0.020_{,rm syst} right)|V_{cd}|^2 :{rm ps}^{-1}$, respectively. The phenomenology of the rare charm decay $Lambda_c to p, mu^+ mu^-$ is also studied. The differential branching fraction, the fraction of longitudinally polarized dimuons, and the forward-backward asymmetry are calculated in the Standard Model and in an illustrative new-physics scenario.
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