B -> X-s gamma gamma decay in the standard model and the general two-Higgs-doublet model - art. no. 014012

Based on the low-energy effective Hamiltonian, we calculate new physics cor rections to the branching ratio and the differential distributions of the r are decay B-->X(s)gamma gamma induced by the new gluonic and electroweak ch arged-Higgs penguin diagrams in the general two-Higgs-doublet model with th e restriction lambda (U,D)(ij) = 0 for i not equal j. Within the considered parameter space, we see the following: (a) the standard model predictions of B(B-->X(s)gamma gamma) and A(FB) have a moderate m(s) dependence; (b) in model III, the prediction of the branching ratio B(B-->X(s)gamma gamma) ra nges from one-third to three times the standard model prediction, but is hi ghly correlated with that of B(B-->X(s)gamma); (c) the new physics enhancem ent to the branching ratio B(B-->X(s)gamma gamma) in model II can be as lar ge as (30-50)%; (d) the contribution from one-particle reducible diagrams i s dominant and hence four normalized differential distributions are insensi tive to the variation of scale mu and possible new physics corrections; (e) because of the smallness of its decay rate and the long-distance backgroun d, the B-->X(s)gamma gamma decay is not a better process in detecting new p hysics than the B-->X(s)gamma decay.