Study on pure annihilation type B to V gamma decays

Abstract

We investigate the pure annihilation type radiative $B$ meson decays $B^0\to \ddot{I}•{\hat{I}}^3$ and $B_s\to \ddot{I}{}^0(\ddot{I}‰){\hat{I}}^3$ in the soft-collinear effective theory. We consider three types of contributions to the decay amplitudes, including the direct annihilation topology, the contribution from the electro-magnetic penguin operator and the contribution of the neutral vector meson mixings. The numerical analysis shows that the decay amplitudes are dominated by the $\ddot{I}‰-\ddot{I}•$ mixing effect in the $B^0\to \ddot{I}•{\hat{I}}^3$ and $B_s\to \ddot{I}‰{\hat{I}}^3$ modes. The corresponding decay branching ratios are enhanced about three orders of magnitudes relative to the pure annihilation type contribution in these two decay channels. The decay rate of $B_s\to \ddot{I}{}^0{\hat{I}}^3$ is much smaller than that of $B_s\to \ddot{I}‰{\hat{I}}^3$ because of the smaller $\ddot{I}{}^0-\ddot{I}•$ mixing. The predicted branching ratios $B(B^0\to \ddot{I}•{\hat{I}}^3)=(3.99_{-1.46}^{+1.67})\times 10^{-9},B(B_s\to \ddot{I}‰{\hat{I}}^3)=(2.01_{-0.71}^{+0.81})\times 10^{-7}$ are to be tested by the Belle-II and LHC-b experiments.

radiative decay, annihilation topology, vector meson mixing