A lattice QCD determination of the ${\mathrm{\Lambda }}_c\to N$ 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 $a\approx 0.11$ and 0.085 fm and pion masses in the range $230\mathrm{MeV}\lesssim m_{\pi }\lesssim 350\mathrm{MeV}$. 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 ${\mathrm{\Lambda }}_c\to n{e}^{+}{\nu }_e$ and ${\mathrm{\Lambda }}_c\to n{\mu }^{+}{\nu }_{\mu }$ are predicted to be $(0.405\pm 0.016_{\mathrm{stat}}\pm 0.020_{\mathrm{syst}})|V_{cd}{|}^2{\mathrm{ps}}^{-1}$ and $(0.396\pm 0.016_{\mathrm{stat}}\pm 0.020_{\mathrm{syst}})|V_{cd}{|}^2{\mathrm{ps}}^{-1}$, respectively. The phenomenology of the rare charm decay ${\mathrm{\Lambda }}_c\to p{\mu }^{+}{\mu }^{-}$ 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.

• Received 28 December 2017

DOI:https://doi.org/10.1103/PhysRevD.97.034511

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society