EFFECT OF THE HAIRPIN DIAGRAM ON 2-BODY NONLEPTONIC B-DECAYS AND CP VIOLATION

A careful quark-diagram analysis shows that a number of two-body nonleptonic B decays can occur through the so-called hairpin diagram, a QCD loop-induced graph different from the penguin one in final-state hadronization of valence quarks. Using the two-loop renormalization-group-improved effective Hamiltonian and the naive factorization approximation, we demonstrate the effect of the hairpin diagram on decay rates and CP asymmetries for a few interesting channels such as B(d)0,B(d)0BAR --> psiK(s) and B(u)+/- --> phiK+/-. Branching ratios of some pure hairpin decay modes, e.g., B(u)- -->phipi-, phirho- and B(d)0BAR --> phipi0, phirho0, phiomega, phieta, etc., are estimated to be on the order of 10(-7).