Lepton flavor violating ${\Lambda }_b\to \Lambda {\ell }_1{\ell }_2$ decay

Abstract

Inspired by the recent hints of lepton flavor universality violation in $b\to s\ell \ell$ and $b\to c\ell \nu$ transitions, we study lepton flavor violating exclusive ${\Lambda }_b\to \Lambda {\ell }_1^{+}{\ell }_2^{-}$ (${\ell }_1\ne {\ell }_2$) decay, which is forbidden in the Standard Model. Starting from a general effective Hamiltonian for a $b\to s{\ell }_1^{+}{\ell }_2^{-}$ transition that includes vector and axial-vector operators, and scalar and pseudo-scalar operators, we derive a two-fold decay distribution of ${\Lambda }_b\to \Lambda {\ell }_1^{+}{\ell }_2^{-}$. The distribution helps us to construct the differential branching ratio and the lepton side forward-backward asymmetry, which are studied in a vector leptoquark model. The parameter space of the vector leptoquark model is constrained by low energy observables.

Comments: 9 pages, two figures, published in EPJC, matches published version