Nonleptonic charmlessBcdecays and their search at LHCb

Abstract

We discuss the decay of B c mesons into two light mesons (π, K ( * ) , η (′) , ρ, ω, φ ). All these decay channels come from a single type of diagram, namely tree annihilation. This allows us to derive extremely simple SU(3) relations among these processes. The size of annihilation contributions is an important issue in B physics, and we provide two different estimates in the case of non-leptonic charmless B c decays, either a comparison with annihilation decays of heavy-light mesons or a perturbative model inspired by QCD factorisation. We finally discuss a possible search for these channels at LHCb.

Study ofBc→KKdecay with perturbative QCD approach

“…Both the estimations in [15,16] and our result are in accordance with an intuitive expectation for nonleptonic charmless W -annihilation of heavy meson decays which are usually suppressed. There are some additional factors for the tiny estimation of BR(B c →KK).…”

“…In addition, the branching ratio of the charmless decay B c → KK is estimated to be O(10 −8 ) with the QCDF approach [15]. Recently, this charmless decay is also studied with the pQCD approach and its branching ratio is O(10 −7 ) with the off-mass-shell final states [16], which is the same order of magnitude as ours obtained in this paper with the on-shell final states.…”

“…[14] obtains a very large B c → KK branching ratio, about 1.6%, at 4 orders of magnitude bigger than the estimate O(10 −6 ) of Ref. [15], but this estimate is not valid because Ref. [14] in their calculation incorrectly uses the measured penguin-dominated B ± u →π ± K branching ratio while the decay B c → KK is a pure tree weak annihilation and should be related to…”

Branching ratios ofBcmeson decaying to vector and axial-vector mesons

“…We wish to emphasize that with remarkable improvements in experiment and sophisticated instrumentation branching ratios of the order of (10 −6 ) could be measured precisely [39] at LHC, LHC-b and Super-B factories in near future. Therefore, it may provide the necessary information for phenomenological study of B c meson physics.…”

Study of Bc→DS decays in the perturbative QCD approach

“…All in all, the B c meson provides very rich weak decay channels to study perturbative and nonperturbative QCD dynamics and the annihilation mechanism of the B meson, to test the standard model, as well as to search for signals of new physics [5]. In recent years, stimulated by both theoretical and experimental developments, many theoretical studies on the production and the semileptonic and nonleptonic decays of the B c meson have been explored by many groups based on the Isgur-Scora-Grinstein-Wise quark model [6], the relativistic independent quark model [7], QCD factorization [8,9], the light-front quark model [9], SU(3) flavor symmetry [10], lattice gauge simulations [11], sum rules [12], nonrelativistic QCD methods [13], and the perturbative QCD (PQCD) approach [14][15][16].…”