Lepton Flavor Violation in Exclusive $b\to s$ Decays

TL;DR

This paper derives angular distributions and branching ratios for lepton flavor violating $b o s$ decays, exploring new physics scenarios including scalar couplings from Higgs decays and $Z'$ models, providing numerical estimates.

Contribution

It presents a comprehensive framework for analyzing lepton flavor violation in $b o s$ decays, incorporating new physics scenarios and deriving explicit angular and branching ratio formulas.

Findings

Derived full angular distributions for $B o K^{(*)} au au'$ decays.

Estimated branching ratios under scalar coupling and $Z'$ model scenarios.

Highlighted differences between lepton flavor violating and conserving modes.

Abstract

Starting from the general effective hamiltonian relevant to the $b\to s$ transitions, we derive the expressions for the full angular distributions of the $B \to K^{(\ast )} \ell_1 \ell_2$ decay modes, as well as for ${\cal B}(B_s \to \ell_1\ell_2 )$ ($\ell_1\neq \ell_2$). We point out the differences in the treatment of the lepton flavor violating modes with respect to the lepton flavor conserving ones. Concerning the relevant Wilson coefficients we evaluate them in two different scenarios: (i) The (pseudo-)scalar coefficients are obtained using the (pseudo-)scalar coupling extracted from the experimental non-zero value of ${\cal B}(h\to \mu\tau)$, (ii) Revisiting a $Z^\prime$-model in which the flavor changing neutral couplings are allowed. We provide the numerical estimates of the branching fractions of the above-mentioned modes in both scenarios.