The influence of invisible light particles on $\Lambda_b \to \Lambda E_{\mathrm{miss}}$

Abstract

In this work, we study the contribution of invisible light particles to $\Lambda_b \to \Lambda E_{\mathrm{miss}}$, particularly the three-body decays $\Lambda_b \to \Lambda \phi \bar\phi$ and $\Lambda_b \to \Lambda \psi \bar\psi$. The differential branching ratio of $\Lambda_b \to \Lambda E_{\mathrm{miss}}$ and the $q^2$-dependent longitudinal polarization asymmetry of $\Lambda$ in scenarios explaining the Belle II excess are presented. In the chiral basis, we investigate the correlations between $\mathcal{B}(B \to K E_{\mathrm{miss}})$ and $\mathcal{B}(\Lambda_b \to \Lambda E_{\mathrm{miss}})$, as well as between $\mathcal{B}(B \to K E_{\mathrm{miss}})$ and $P^{\Lambda}_{L}$, in eight distinct new physics scenarios. We find that the $P^{\Lambda}_{L}$ can be used to distinguish the chirality of the hadronic current part in the effective operators, which is similar to the cases in the two-body decays $\Lambda_b \to \Lambda \phi$ and $\Lambda_b \to \Lambda V$.