Analysis of charmless two-body B decays in factorization-assisted topological-amplitude approach

Abstract

We analyze charmless two-body non-leptonic B decays B → P P, P V under the framework of factorization assisted topological amplitude approach, where P (V ) denotes a light pseudoscalar (vector) meson. Compared with the conventional flavor diagram approach, we consider flavor SU (3) breaking effect assisted by factorization hypothesis for topological diagram amplitudes of different decay modes, factorizing out the corresponding decay constants and form factors. The non-perturbative parameters of topology diagram magnitudes χ and strong phase φ are universal that can be extracted by χ 2 fit from current abundant experimental data of charmless B decays.The number of free parameters and the χ 2 per degree of freedom are both reduced comparing with previous analysis. With these best fitted parameters, we predict branching fractions and CP asymmetry parameters of nearly 100 B u,d and B s decay modes. The long-standing ππ and πK-CP puzzles are resolved simultaneoulsy. PACS numbers:Recently, an additional Glauber phase is introduced to solve this puzzle [11].Unlike the above mentioned perturbative approaches, some model-independent approaches were introduced to analyze the charmless B decays, such as global SU (3)/U(3) flavor symmetry analysis [12] and flavor topological diagram approach [13, 14]. They do not apply factorization in QCD, leaving all perturbative or non-perturbative QCD effects extracted from experimental data. In [12], they related relevant decay amplitudes using SU(3)/U(3) group decomposition and then extract them form experimental data. For the flavor topological diagram approach, they group different contributions according to the electroweak topological diagram, since electroweak interaction naturally factorize from QCD interaction. Each topological diagram amplitude including all strong interactions with strong phase are to be extracted from experimental data. However, in order to reduce the number of free parameters, it needs to apply the flavor SU(3) symmetry to relate topological diagram parameters of different decay modes. In fact, the flavor SU(3) symmetry is broken.Nowadays, SU(3) breaking effect have to be considered to compare the theoretical results with the precise experimental data. It is also observed in the flavor topological diagram analysis that there are large differences among the three types of B → P P , B → P V and B → V P decays due to different pseudoscalar and vector final states. Therefore, they have to fit three different sets of parameters for the three types of B decays respectively [14].

Charmless Hadronic Beauty Decays at LHCb

“…This result is consistent with the lower end of the range of predictions available for this branching fraction; the central values of several predictions are inconsistent with this result, see for example Refs. [29,[32][33][34]. This result therefore provides very useful constraints on the theoretical models used to predict branching fractions and CP asymmetries of charmless B 0 s decays to a pseudoscalar and vector meson final state.…”

“…Additional uncertainties arise due to the limited size of the simulation samples and the corresponding uncertainty on the distribution of the efficiencies across the decay phase space. As the efficiencies depend on the signal decay-time distribution, the e↵ect coming from the di↵erent lifetimes of the B 0 s mass eigenstates has been evaluated [34]. Pseudoexperiments are used to estimate the e↵ect of using alternative shapes for the fit components, of including additional backgrounds in the fit such as partially reconstructed decays, and of excluding the B 0 !…”

Search for the B s 0 → η′ϕ decay

“…Although large theoretical uncertainties make most predictions compatible with the result of this analysis, the central values of the predictions in refs. [6][7][8][9] are significantly larger than the upper limit. These discrepancies should help in constraining the theoretical models used in the prediction of branching fractions and CP asymmetries for B-meson hadronic charmless decays.…”

“…2 The notations η and φ refer to the η (958) and φ(1020) mesons. in the framework of QCD factorisation [3,4], perturbative QCD [5,6], soft-collinear effective theory (SCET) [7], SU(3) flavour symmetry [8], and factorisation-assisted topological (FAT) amplitude approach [9]. Table 1 presents the available predictions for B(B 0 s → η φ).…”

Hadronic decays of B→a1(1260)b1(1235Jing1, Liu2, Xiao3 2017Phys. Rev. D1000View full textAdd to dashboardCite

“…The great efforts have been extensively contributed to the exclusive B → P P, P V, and V V decays at both theoretical and experimental aspects in the past decades, for example, see Refs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], where P and V denote the S-wave pseudoscalar and vector states, respectively. However, the known "puzzles", for example, the large observed B 0 → π 0 π 0 , B 0 → ρ 0 π 0 , and B → Kη ′ decay rates, the experimental inequality of the direct CP asymmetries between B ± → K ± π 0 and B 0 → K ± π ∓ modes, the unknown mechanism of the polarization in the penguin-dominated B → V V processes etc., are still not elegantly resolved [17][18][19].…”