B→η(′)(l−ν¯l,l

Revisiting charmless hadronicBu,ddecays in QCD factorization

“…On the other hand, the predicted A CP (K * 0 η) is too small. So far the pQCD results for A CP (K * η ( ′ ) ) are quoted from [53] where m qq = 0.22 GeV is used. Since the pQCD study of B → Kη ( ′ ) has been carried to the (partial) NLO and a drastic different prediction for A CP (K − η) has been found, it will be crucial to generalize the NLO calculation to the K * η ( ′ ) sector.…”

“…Many possible solutions to the puzzle for the abnormally large Kη ′ rate have been proposed in the past: (i) a significant flavor-singlet contribution [15,50], (ii) a large B → η ′ form factor [51], (iii) a contribution from the charm content of the η ′ , (iv) an enhanced hadronic matrix element 0|sγ 5 s|η ′ due to the axial U(1) anomaly [52], (v) a large chiral scale m q 0 associated with the η q [53,54], (vi) a long-distance charming penguin in SCET [55], and (vii) a large contribution from the two-gluon fusion mechanism [56].…”

“…First, the pQCD prediction for A CP (K − η) is very sensitive to m qq , the mass of the η q , which is generally taken to be of order m π . It was found in [53] that for m qq = 0.14, 0.18 and 0.22 GeV, A CP (K − η) becomes 0.0562, 0.0588 and −0.3064, respectively. There are two issues here: (i) Is it reasonable to have a large value of m qq ?…”

Measurement of branching fractions andCPviolation parameters inB→ωKdecays with first evidence ofCPviola

“…We reconstruct B 0 → ωK 0 S from Υ(4S) → B 0B0 decays. As the two B mesons are produced in a coherent state, the B 0 Rec flavor can be obtained from the other [16,17], QCDF [18], SCET 1 [19] and SCET 2 [19] theoretical predictions for the B 0 → ωK 0 S and B + → ωK + branching fractions (in units of 10 −6 ) and CP parameters (in units of 10 −2 ). The meaning of each uncertainty for these approaches is given in the corresponding references.…”

Observation of the decayB0→η′K*(892Sato1, Yusa2, Mohanty3 et al. 2014Phys. Rev. D7010View full textAdd to dashboardCite

“…The decay B 0 → η ′ K * (892) 0 has been studied extensively within the framework of perturbative QCD [9], QCD factorization [10], soft collinear effective theory [11] as well as SU (3) flavor symmetry [12], and predicted branching fractions are in the range (1.2−6.3)×10 −6 . In the past, both Belle [13] and BABAR [14] have searched for B 0 → η ′ K * (892) 0 with the latter reporting the first evidence with a significance of 4.0 standard deviations (σ).…”