New physical effects on the decay $B_{s(d)} \to \gamma\gamma$ in the sequential fourth Generation model

TL;DR

This paper investigates how a sequential fourth generation of quarks could significantly alter the predicted branching ratios of the rare decays $B_{s(d)} o \gamma\gamma$, providing potential signals for new physics beyond the Standard Model.

Contribution

It introduces the effects of a sequential fourth generation and the new CKM4 matrix on $B_{s(d)} o \gamma\gamma$ decay predictions, showing possible large enhancements over the SM.

Findings

Branching ratios are significantly affected by the fourth generation.

CKM4 matrix factors can enhance decay rates by over an order of magnitude.

$B_{s(d)} o \gamma\gamma$ decays can serve as probes for new physics signals.

Abstract

We study the contributions to the branching ratios of $B_{s(d)}\to \gamma \gamma$ decay in the sequential fourth generation model (SM4). We find that the theoretical values of the branching ratios, ${\rm BR}(B_{s(d)}\to\gamma\gamma)$, including the contributions of $m_{t'}$ and the new $4 \times 4$ CKM (CKM4) matrix factors, $|V^{*}_{t's}V_{t'b}|$ and $|V^{*}_{t'd}V_{t'b}|$, are much different from the minimal standard model (SM) predictions. The new physics effects, especially contributed from the CKM4 matrix factors, can provide more than one order enhancement to the SM prediction. It is shown that the decay $B_{s(d)}\to \gamma \gamma$ can test the new physics signals from SM4.