Z. J. Xiao

Branching ratio and CP asymmetry of B(s) ---> pi+ pi- decays in the perturbative QCD approach

In this paper, we calculate the decay rate and CP asymmetry of the

Branching ratios and C P asymmetries of B → K η ( ′ ) decays in the perturbative QCD approach

{B}_{s}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}

Branching ratio and CP asymmetry of B ---> pi eta-(prime) decays in the perturbative QCD approach

decay in the perturbative QCD approach with Sudakov resummation. Since none of the quarks in final states is the same as those of the initial

Rare decays B-0 -> D(*)(s)+D(*)(s)- and B-s(0)-> D(*)+D(*)(-) in perturbative QCD approach

{B}_{s}

Charmless B{yields}PV,VV decays and new physics effects in the minimal supergravity model

meson, this decay can occur only via annihilation diagrams in the standard model. Besides the current-current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. We find that (a) the branching ratio is about

The S-wave resonance contributions to the three-body decays

4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7};

B^0_{(s)}\rightarrow \eta _c f_0(X)\rightarrow \eta _c\pi ^+\pi ^-

(b) the penguin diagrams dominate the total contribution; and (c) the direct CP asymmetry is small in size: no more than 3%; but the mixing-induced CP asymmetry can be as large as 10% testable in the near future LHC-b experiments.

in perturbative QCD approach

Abstract We calculate the branching ratios and CP violating asymmetries of the four B → Kη(′) decays in the perturbative QCD (pQCD) factorization approach. Besides the full leading order contributions, the partial next-to-leading order (NLO) contributions from the QCD vertex corrections, the quark loops, and the chromo-magnetic penguins are also taken into account. The NLO pQCD predictions for the CP-averaged branching ratios are Br(B+ → K+η) ≈ 3.2 × 10−6, Br(B± → K±η′) ≈ 51.0 × 10−6, Br(B0 → K0η) ≈ 2.1 × 10−6, and Br(B0 → K0η′) ≈ 50.3 × 10−6. The NLO contributions can provide a 70% enhancement to the LO Br(B → Kη′), but a 30% reduction to the LO Br(B → Kη), which play the key role in understanding the observed pattern of branching ratios. The NLO pQCD predictions for the CP-violating asymmetries, such as Adir CP (K0 Sη) ∼ 2.3% and Amix CP (K0 Sη) ∼ 63%, agree very well with currently available data. This means that the deviation ∆S = Amix CP (K0 Sη) − sin 2β in pQCD approach is also very small.

NLO twist-3 contribution to the pion electromagnetic form factors in

Abstract We calculate the branching ratios and CP-violating asymmetries for B 0 → π 0 η ( ′ ) and B + → π + η ( ′ ) decays in the perturbative QCD (pQCD) factorization approach here. We not only calculate the usual factorizable contributions, but also evaluate the non-factorizable and annihilation type contributions. Besides the current–current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. The pQCD results for the CP-averaged branching ratios are Br ( B + → π + η ) ≈ 4.1 × 10 −6 , Br ( B + → π + η ′ ) ≈ 2.4 × 10 −6 , and Br ( B 0 → π 0 η ( ′ ) ) ≈ 0.2 × 10 −6 , which agree very well with the measured values or currently available experimental upper limits. We also predict large CP-violating asymmetries in these decays: A CP dir ( π ± η ( ′ ) ) ∼ A CP dir ( π 0 η ( ′ ) ) ∼ − 0.35 , and A CP mix ( π 0 η ( ′ ) ) ∼ 0.67 , but with large errors. The pQCD prediction for A CP dir ( π ± η ) ( A CP dir ( π ± η ′ ) ) has the same (opposite) sign with the primary measured values. Further improvements in both theory and experiments are needed to clarify this discrepancy.

k_T

In decay modes B-0 --> Ds(*)+Ds(*)- and B-s(0) --> D(*)+D(*)-, none of the quarks in final states is the same as the one of the B(B-s) meson. They can only occur via annihilation diagrams in the standard model. In the heavy quark limit, we try to calculate the branching ratios of these decays in the perturbative QCD approach without considering the soft final state interaction. We found branching ratios of B-0 --> Ds(*)+Ds(*)- are of the order of 10(-5), and branching ratios of B-s(0) --> D(*)+D(*)- are of 10(-3). Those decay modes will be measured s in B factories and LHC-b experiments.