Flavor physics with ${\Lambda }_b$ baryons

Abstract

At the LHC, bottom baryons are being produced in unprecedented quantities, which opens up a new field for flavor physics. For example, the decay ${\Lambda }_b\to p{\mu }^{-}\bar{\nu }$ can be used to obtain a novel determination of the CKM matrix element $|V_{ub}|$, and the decay ${\Lambda }_b\to \Lambda {\mu }^{+}{\mu }^{-}$ probes the weak interactions at the loop level. The first lattice calculations of the relevant ${\Lambda }_b\to p$ and ${\Lambda }_b\to \Lambda$ 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 ${\Lambda }_b\to p$, ${\Lambda }_b\to \Lambda$, and ${\Lambda }_b\to {\Lambda }_c$ form factors using a relativistic heavy-quark action.

Comments: 15 pages, 12 figures, plenary talk presented at the 31st International Symposium on Lattice Field Theory (Lattice 2013), 29 July - 3 August 2013, Mainz, Germany