${\Lambda }_b\to \Lambda (\to p{\pi }^{-}){\ell }^{+}{\ell }^{-}$ as probe of CP-violating New Physics

Abstract

We investigate the possible sizes of all the CP-violating asymmetries offered by the angular distribution of rare decay ${\Lambda }_b\to \Lambda (\to p{\pi }^{-}){\ell }^{+}{\ell }^{-}$ in the Standard Model and new physics scenarios motivated by the recent $b\to s{\ell }^{+}{\ell }^{-}$ anomalies. We work in a model-independent effective theory framework and discuss the sensitivity of CP asymmetries to new $O_{9,10}$ operators and their chirality flipped counterparts. We find that the size of many of the CP asymmetries can be at the level of a few percent in new physics scenarios consistent with current $b\to s{\ell }^{+}{\ell }^{-}$ data at a level of $1\sigma$. We emphasize that measurements of these CP asymmetries can be used to discriminate different new physics scenarios in $b\to s{\ell }^{+}{\ell }^{-}$.

Comments: 28 pages, 4 captioned figures; updated NP benchmarks following the latest RK(*) measurements; matches journal version