Rare decays of the $B_s-$meson into four charged leptons in the framework of the Standard Model

Abstract

In the framework of the Standard Model we present new theoretical predictions for the branching ratios, double and single differential distributions and forward -- backward leptonic asymmetries for the $\bar B_s \to \mu^+ \mu^- e^+ e^-$ decay. In our consideration we take into account the $\phi(1020)$ -- resonance contribution; the main contributions of four charmonium resonances : $\psi(3770)$, $\psi(4040)$, $\psi(4160)$ and $\psi(4415)$; $u\bar{u}$ -- resonant contribution from $\rho(770)$ and $\omega(782)$; tails contributions from $J/\psi$ and $\psi(2S)$ resonances; non -- resonant contribution of the $b\,\bar{b}$ - pairs, bremsstrahlung and the contribution of the weak annihilation. We provide the prediction for the branching ratio of $\bar B_s \to \mu^+ \mu^- e^+ e^-$ decay with and without the $\phi(1020)$ -- resonance contribution. We use the model of vector meson dominance (VMD) for calculation of resonances contributions and take into account all substantive terms in $\bar B_s \to \mu^+ \mu^- e^+ e^-$ amplitude that was not considered in the previously papers.