Estimating the annihilation decay B_s -> rho gamma with factorization

TL;DR

This paper calculates the rare B_s -> rho gamma decay rate using factorization, estimates its Standard Model value, and explores potential enhancements from new physics models like vector quarks and supersymmetry.

Contribution

It provides the first estimate of the branching ratio for B_s -> rho gamma within the Standard Model and assesses its sensitivity to specific new physics scenarios.

Findings

Standard Model branching ratio estimated at 1.6 x 10^-9.

Vector quark model can increase the rate by up to 10%.

Supersymmetry effects are negligible.

Abstract

The branching ratio for the rare two-body B_s -> rho gamma decay is calculated using the factorization assumption. This transition is dominated by the annihilation diagrams and, in principle, prone to receiving substantial contributions from new physics. We estimate Br(B_s -> rho gamma) = 1.6 x 10^-9 within the Standard Model and investigate the sensitivity of this decay mode to the effects of two new physics scenarios: vector quark model and supersymmetry. Our results indicate that the shift in branching ratio is at most around 10% with the addition of vector quarks and is negligibly small in the constrained minimal supersymmetric extension of the Standard Model.