Exclusive charmless Bs hadronic decays into η′ and η

Abstract

Using the next-to-leading order QCD-corrected effective Hamiltonian, charmless exclusive nonleptonic decays of the B s meson into η or η ′ are calculated within the generalized factorization approach. Nonfactorizable contributions, which can be parametrized in terms of the effective number of colors N eff c for P P and V P decay modes, are studied in two different schemes: (i) the one with the "homogeneous" structure in which (is assumed, and (ii) the "heterogeneous" one in which the possibility ofis considered, where N eff c (V + A) denotes the effective value of colors for the (V − A)(V + A) penguin operators and N eff c (V − A) for the (V − A)(V − A) ones. For processes depending on the N eff c -stable a i such as B s → (π, ρ)(η ′ , η), the predicted branching ratios are not sensitive to the factorization approach we choose. While for the processes depending on the N eff c -sensitive a i such asB s → ωη ( ′ ) , there is a wide range for the branching ratios depending on the choice of the N eff c involved. We have included the QCD anomaly effect in our calculations and found that it is important forB s → η ( ′ ) η ( ′ ) . The effect of the (cc) → η ′ mechanism is found to be tiny due to a possible CKM-suppression and the suppression in the decay constants except for theB s → φη decay within the "naive" factorization approach, where the internal W diagram is CKM-suppressed and the penguin contributions are compensated.

Phenomenological analysis of charmless decaysBs→PP,PVwith QCD factorization

“…There are many works devoted to the study of exclusive B decays into two-body final states containing η (′) , such as Refs. [30,56]. It is generally believed that this problem is related to the axial anomaly in QCD, but the dynamical details remain unclear.…”

“…[25,26,27,28,29]. The investigation on the exclusive charmless B s decays into final states containing η (′) meson was given within the generalized factorization framework [30]. Chen, Cheng, and Tseng calculated carefully the branching ratios for charmless decays B s → P P , P V , V V (here P and V denote pseudoscalar and vector mesons respectively) [31].…”

“…And new physics effects in B s decays was considered in [32]. It is found that the electroweak penguin contributions can be large for some decays modes [29,31], and that branching ratios for B s → ηη ′ and several other decay modes can be as large as 10 −5 [30,31,32] which is measurable at future experiments.…”

Erratum: CharmlessB¯s→VVdecays in QCD factorization [Phys. Rev. D68, 114015 (2003)]

“…In the papers [11,12], the authors have studied systematically the B s → P P, P V decays(here P , V denote pseudoscalar and vector mesons respectively) with QCD factorization, and intensive phenomenological analysis has been made. Since the B → V V modes reveal dynamics of exclusive B meson decays more than the the B → P P and P V modes through the measurement of the magnitudes and the phases of various helicity amplitudes, in the present work we plan to make a detail study of B s → V V decays within the same framework of QCD factorization.…”

Connecting b → s ℓ ℓ ¯ $$ b\to s\ell \overline{\ell} $$ anomalies to enhanced rare nonleptonic

“…The product of Cabibbo-KobayashiMaskawa (CKM) matrix elements in the tree contributions is suppressed compared to that in the EWP ones, and the suppression factor is |V us V ub |/|V ts V tb | ∼ 0.02. Consequently, although the Wilson coefficients of the tree operators are much bigger than those of the EWP operators, the latter turn out to dominate the majority of these channels, and the resulting decay rates are relatively low [26][27][28][29]. Most of them are not yet observed, the exception beingB s → φρ 0 .…”