Fourth generation effects on the rare $B\to K^{\ast }\nu \bar{\nu }$ decay

Abstract

If the fourth generation fermions exist, the new quarks could influence the branching ratio of the rare $B\to K^{\ast }\nu \bar{\nu }$ decay. Two possible solutions of the fourth generation CKM factor $(V_{\acute{t}s}^{\ast }{V}_{\acute{t}b}{)}^{(}\pm )$ are obtained as a function of the new $\acute{t}$-quark mass $(m_{\acute{t}})$ from the experimental results of the $B\to X_s\gamma$ together with the semileptonic decay $B\to X_c\ell \bar{\nu }$. The branching ratio of the decay $B\to K^{\ast }\nu \bar{\nu }$ in the two cases is estimated. In one case, a significant enhancement to the branching ratio of the decay $B\to K^{\ast }\nu \bar{\nu }$ over the SM is recorded, while results are almost same in another case. If a fourth generation should exist in nature and nature chooses the former case, this B meson decay could be a good probe to the existence of the fourth generation, or perhaps a signal for a new physics.

Comments: 15 pages, 4 figures