B → X_sγ in BLMSSM

Applying the effective Lagrangian method,we study the flavor changing neutral current process b→ sγwithin the minimal supersymmetric extension of the Standard Model,where baryon and lepton numbers are local gauge symmetries.Constraints on the parameters are investigated numerically with the experimental data for the branching ratio of B→ X_sγ.Additionally,we present the corrections to direct CP-violation in B→ X_sγ and time-dependent CP-asymmetry in B→K~*γ.With appropriate assumptions on the parameters,we find the direct CP-violation Acp is very small,while one-loop contributions to S_(K~*_γ) can be significant.     

Chiral anomaly in Kγ → Kπ reactions

Implications of the chiral anomaly for the cross sections of the reactions K ⁺γ → K ⁺π⁰, K ⁰γ → K ⁰π⁰, K ⁺γ → K ⁰π⁺, and K ⁰γ → K ⁺π^? are investigated. Near the threshold, the contribution of the chiral anomaly dominates the cross sections for the first and the second reaction. These cross sections are compared with the cross sections for the third and the fourth reaction, which receive no contribution from the chiral anomaly. Prospects for an experimental study of the KKπγ vertex in the Coulomb production of π mesons by a K-meson beam are discussed.     

Inelastic final-state interactions in B → VV →π K processes

We study the final-state interactions in B →π K decays through B → VV →π K processes where the inelastic rescattering occurs via single pion exchange. The next-to-leading order low-energy effective Hamiltonian and Bauer-Stech-Wirbel (BSW) model are used to evaluate the weak transition matrix elements and final-state interactions. We found that the final-state interaction effects in B →ρ K^*→π K processes are significant. The Fleischer-Mannel relation for the Cabibbo-Kobayashi-Maskawa (CKM) angle γ can be significantly modified. Received: 13 August 1998     

Towards B→Vγ decays at NNLO in SCET

We compute NNLO ((α_s ²)) corrections to the hard-scattering kernels entering the QCD factorization formula for B→Vγ decays, where V is a light vector meson. We give complete NNLO results for the dipole operators Q₇ and Q₈, and partial results for Q₁ valid in the large-β₀ limit and neglecting the NNLO correction from hard-spectator scattering. Large perturbative logarithms in the hard-scattering kernels are identified and resummed using soft-collinear effective theory. We use our results to estimate the branching fractions for B→K^*γ and B_s→φγ decays at NNLO and compare them with the current experimental data.     

B→ηK and B→φKs Decays in the Two Higgs Doublet Model Ⅲ

Using the QCD factorization approach, we investigate the large branching ratios of B→ηK^＊ decays and the SCKs anomaly of B→φKs decay in the two Higgs doublet model Ⅲ. With the contributions of flavour-changing neutral current mediated by the neutral Higgs bosons H^0, h^0 and A^0 at the tree level, we provide a coherent resolution to these anomalies within the constrained parameter spaces, which are 120 〈｜λbs λss｜ 〈136. This will be really interesting in searching for the signs of new physics.     

B→K*ℓ+ℓ- decay in soft-collinear effective theory

We study the rare B decay B→K^*ℓ⁺ℓ^- using soft-collinear effective theory (SCET). At leading power in 1/m_b, a factorization formula is obtained valid to all orders in α_s. For phenomenological application, we calculate the decay amplitude including order α_s corrections, and resum the logarithms by evolving the matching coefficients from the hard scale down to the scale . The branching ratio for B→K^*ℓ⁺ℓ^- is uncertain due to the imprecise knowledge of the soft form factors ζ_⊥(q²) and ζ_∥(q²). Constraining the soft form factor ζ_⊥(q²=0) from data on B→K^*γ yields ζ_⊥(q²=0)=0.32±0.02. Using this input, together with the light-cone sum rules to determine the q²-dependence of ζ_⊥(q²) and the other soft form factor ζ_∥(q²), we estimate the partially integrated branching ratio in the range 1 GeV²≤q²≤7 GeV² to be (2.92^+0.67 _-0.61)×10^-7. We discuss how to reduce the form factor related uncertainty by combining data on B→ρ(→ππ)ℓν_ℓ and B→K^*(→Kπ)ℓ⁺ℓ^-. The forward-backward asymmetry is less sensitive to the input parameters. In particular, for the zero-point of the forward-backward asymmetry in the standard model, we get q₀ ²=(4.07^+0.16 _-0.13) GeV². The scale dependence of q₀ ² is discussed in detail. PACS 13.25.Hw, 12.39.St, 12.38.Bx     

The form factors of the decays π− → e−¯veγ and K− → e−¯veγ

In the special type of the quark model we obtain the ratio=h _A/h_V of the axial (h_A) and vector (h_V) form factors for the decays ^– e^– ¯v_e and K^– e^–¯v_e different from unity. The low-energy theorem, relating the electric polarizability of the charged pion with the ratio, is analyzed. It is shown that < 1 corresponds to , calculated by accounting the contribution of the scalar meson(700) into the amplitude of the Compton effect on the pion. In the absence of the(700) contribution we have=1.Dedicated to Academician Václav Votruba on the occasion of his eightieth birthday.     

Observation of the decay Ks → 2γ and measurement of the decay rates KL → 2γ and KS → 2γ

The decay rates of K_L → 2γ and K_S → 2γ have been measured at the CERN SPS. The results are Γ(K_L→2γ)/χ(K_L→2π₀)=0.632±0.004±0.008 and Γ(K_S→2γ)/Γ(K_L→2γ)=2.3 ±1.0±0.4. This is the first observation of K_S→2γ decays.     

B→K0^＊（1430）K Decays in Perturbative QCD Approach

In this article, we calculate the branching ratios of B→K0^＊ （1430）K decays by employing the pertur-bative QCD （pQCD） approach at leading order. We perform the evaluations in the two scenarios for the scalar meson spectrum. We find that （i） The leading order pQCD predictions for the branching ratio Br（B^＋→K^＋K0^＊（1430）^0）are in good agreement with the experimental upper limit in both scenarios, while the pQCD predictions for other considered B→K0^＊（1430）K decay modes are also presented and will be tested by the LHC experiments; （ii） The annihilation contributions play an important role in these considered decays, for B^0→K0^＊（1430）^±K^± decays,for example,which are found to be （1-4）×10^-6.