The B -> X_s gamma gamma decay in the standard model and the general two-Higgs-doublet model
Abstract
Based on the low-energy effective Hamiltonian, we calculate the new physics corrections to the branching ratio and the differential distributions of the rare decay B \to X_s \gamma \gamma induced by the new gluonic and electroweak charged-Higgs penguin diagrams in the general two-Higgs-doublet model with the restriction \lambda_{ij}^{U,D}=0 for i\neq j. Within the considered parameter space, we see the following: (a) the standard model predictions of {\cal B}(B \to X_s \gamma \gamma) and A_{FB} have a moderate m_s dependence; (b) in model III, the prediction of the branching ratio {\cal B}(B \to X_s \gamma \gamma) ranges from one third to three times of the standard model prediction, but is highly correlated with that of {\cal}(B \to X_s \gamma); (c) the new physics enhancement to the branching ratio {\cal B}(B \to X_s \gamma \gamma) in model II can be as large as (30-50)%; (d) the contribution from 1PR diagrams is dominant and hence four normalized differential distributions are insensitive to the variation of scale \mu and possible new physics corrections; (e) due to the smallness of its decay rate and the long-distance background, the B \to X_s \gamma \gamma decay is not a better process in detecting new physics than the B \to X_s \gamma decay.