Flavor physics with ${\mathrm{\Lambda }}_b$ baryons

At the LHC, bottom baryons are being produced in unprecedented quantities, which opens up a new field for flavor physics. For example, the decay ${\mathrm{\Lambda }}_b\to p{\mu }^{-}\bar{\nu }$ can be used to obtain a novel determination of the CKM matrix element $\mathrm{\mid }{V}_{ub}\mathrm{\mid }$, and the decay $\Lambda_b \to \Lambda \mu^+ \mu^-$ probes the weak interactions at the loop level. The first lattice calculations of the relevant ${\mathrm{\Lambda }}_b\to p$ and ${\mathrm{\Lambda }}_b\to \mathrm{\Lambda }$ form factors have recently been performed using domain-wall light quarks and static $b$ quarks. To further reduce the theoretical uncertainty, one has to go beyond the static approximation. Here I present new calculations of ${\mathrm{\Lambda }}_b\to p$, ${\mathrm{\Lambda }}_b\to \mathrm{\Lambda }$, and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c$ form factors using a relativistic heavy-quark action.