The $B\to X_sl^+l^-$ and $B\to X_s \gamma$ decays with the fourth generation

TL;DR

This paper investigates how the potential existence of a fourth-generation quark could alter the decay rates and asymmetries of B meson decays, providing possible experimental tests for new physics beyond the Standard Model.

Contribution

It introduces two solutions for the fourth-generation CKM matrix element and calculates their effects on B decay observables, highlighting potential deviations from the Standard Model.

Findings

One solution predicts significant deviations from SM in B decay observables.

The other solution yields results nearly identical to SM predictions.

Experimental measurements could distinguish between the two scenarios.

Abstract

If the fourth generation fermions exist, the new quarks could influence the branching ratios of the decays of $B\to X_s \gamma$ and $B\to X_sl^+l^-$. We obtain two solutions of the fourth generation CKM factor $V^{*}_{t^{'}s}V_{t^{'}b}$ from the decay of $B\to X_s \gamma$. We use these two solutions to calculate the new contributions of the fourth generation quark to Wilson coefficients of the decay of $B\to X_sl^+l^-$. The branching ratio and the forward-backward asymmetry of the decay of $B\to X_sl^+l^-$ in the two cases are calculated. Our results are quite different from that of SM in one case, almost same in another case. If Nature chooses the formmer, the $B$ meson decays could provide a possible test of the forth generation existence.