Bounds on the compactification scale of two universal extra dimensions from exclusive $b \to s \gamma$ decays

TL;DR

This paper investigates how the presence of two universal extra dimensions affects certain rare B-meson decays, providing bounds on the size of these extra dimensions based on experimental data.

Contribution

It introduces a new physics model with two universal extra dimensions and derives bounds on their compactification scale from exclusive radiative B decays.

Findings

Most stringent bound: 1/R > 710 GeV from B^0 → K^{*0} γ decay

Branching fractions depend on the size of extra dimensions

Provides constraints on extra dimensions using flavor physics data

Abstract

The exclusive radiative $B \to K^* \gamma$, $B \to K^*_2 \gamma$, $B_s \to \phi \gamma$ and $\Lambda_b \to \Lambda \gamma$ decays are studied in a new physics scenario with two universal extra dimensions compactified on a chiral square. The computed branching fractions depend on the size $R$ of the extra dimensions, and a comparison with the available measurements allows us to put bounds on such a fundamental parameter. From the mode $B^0 \to K^{*0} \gamma$ we obtain the most stringent bound: $1 \over R>710$ GeV.