expansion for exclusive and inclusive charm decays

Exclusive nonleptonic decays ofBmesons

“…It has been shown in ref. [5] that factorization holds in the limit of large number of colours N c in QCD. The leading 1/N c corrections to this limit have also been considered.…”

Effect of the hairpin diagram on two-body nonleptonic B decays and CP violation

“…In the next section we shall analyze the effect of the hairpin diagram on some two-body nonleptonic B decays by means of the two-loop renormalization-group-improved effective Hamiltonian for ∆B = ±1 transitions [3] and the naive factorization approximation [5]. Now we classify a number of two-body mesonic B decays which can get contributions from the hairpin diagram.…”

“…Considering the approximate rule of discarding 1/N c corrections in exclusive nonleptonic B decays [5], we shall take both N c = 3 and N c = ∞ to give one a feeling of N c dependence in this factorization approach. Our numerical results of branching ratios for some pure hairpin channels are listed in Table 1.…”

“…By means of the approaches of the quark diagram analysis and the naive factorization approximation [5], we find a few pure hairpin channels such as B − u → φπ − , φρ − and B 0 d → φπ 0 , φρ 0 , whose branching ratios are on the order of 10 −7 . We also demonstrate the hairpin contributions toB 0 d → ψK 0 , B − u → φK − , etc., which are interesting for probing CP violation in the B-meson system [6].…”

D MESON HADRONIC DECAYS AT CLEO-c

“…Most often, simplified assumptions, such as factorization 33,34 are used to estimate the needed branching ratios. Some dynamical approaches, such as QCD sum rules, have been used to justify those assumptions 35 .…”