CP violation and strong phases from penguins in B±→PP and B±→VP decays

We calculate direct CP-violating rate asymmetries in chargedB→PP andB→VP decays arising from the interference of amplitudes with different strong and CKM phases. The perturbative strong phases develop at order α _s from absorptive parts of one-loop matrix elements of the next-to-leading logarithm corrected effective Hamiltonian. CPT constraints are maintained. Based on this model, we find that partial rate asymmetries between charge conjugateB ^± decays can be as high as 20% for certain channels with branching ratios in the 10^?6 range. Because the $c\bar c$ threshold lies so close to the physical momentum scale, the asymmetries depend sensitively on the model assumptions used to evaluate the imaginary parts of the matrix elements, in particular, on the internal momentum transfer. The charge asymmetries of partial rates would provide unambiguous evidence for direct CP violation.     

Study of K ± → e ± νπ 0 decays at the KMN setup

K ^± → e ^± νπ ⁰ decays have been studied using the KMN setup at the Institute for High Energy Physics (Protvino). The experiment has been performed in the 36-GeV/c hadron beams of the IHEP accelerator. The accumulated data allow us to select ～1.08M candidates for K _e3 decays. Analyzing the Dalitz plot of these events, we estimate the linear slope of the charge form factor to be λ ₊ = [30.44 ± 0.83(stat.) ± 0.74(syst.)] × 10^?3.     

Study of the reaction γp → pπ0η

The reaction γp → pπ⁰η has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction shows contributions from Δ⁺(1232)η , N(1535)⁺π⁰ and pa ₀(980) as intermediate states. A partial-wave analysis suggests that the reaction proceeds via formation of six Δ -resonances, Δ(1600)P ₃₃ , Δ(1920)P ₃₃ , Δ(1700)D ₃₃ , Δ(1940)D ₃₃ , Δ(1905)F ₃₅ , Δ(2360)D ₃₃ , and two nucleon resonances N(1880)P ₁₁ and N(2200)P ₁₃ , for which pole positions and decay branching ratios are given.     

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→f0(980)(π,η') decays in the PQCD approach

Based on the assumption of a two-quark structure of the scalar meson f0(980), we calculate the branching ratios and CP-violating asymmetries for the four B→f0(980)π and B→f0(980)η(') decays by employing the perturbative QCD (Pqcd) factorization approach. The leading order Pqcd predictions for branching ratios are, Br(B-→f0(980)π-)～2.5×10-6, Br(B0→f0(980)πo)～2.6×10-7, Br(B0→f0(980)η)～ 2.5×10-7 and Br(B0→f0(980)η')～6.7×10-7, which are consistent with both the QCD factorization predictions and the experimental upper limits.     

Study of B s 0 → µ+µ− and B d 0 → µ+µ− decays in flavor-changing Z′ models

Recently, the first evidence for the decay B _s ⁰ → μ ⁺ μ ^? has been announced by the LHCb Collaboration and the measured branching ratio B( _s ⁰ → μ ⁺) = (3.2 _?1.2 ^+1.5 ) × 10^?9 is in good agreement with the standard model (SM) expectation. It has also reported an upper limit for B(B _d ⁰ → μ ⁺ μ ^?) < 9.4 × 10^?10 at 95% confidence level. In this paper, we study the B _s ⁰ → μ ⁺ μ ^? and B _d ⁰ → μ ⁺ μ ^? rare decays in flavor-changing Z′ model. Our estimated branching ratios are enhanced from their SM values and provide signals for new physics.     

B→K_0~*(1430)η~(') decays in the pQCD approach

Based on the assumption of two-quark structure of the scalar meson K*0(1430),we calculate the CP-averaged branching ratios for B→K0*(1430)η(') decays in the framework of the perturbative QCD(pQCD) approach here.We perform the evaluations in two scenarios for the scalar meson spectrum.We find that:(a) the pQCD predictions for Br(B→K*0(1430)η(')) which are about 10-5-10-6,basically agree with the data within large theoretical uncertainty;(b) the agreement between the pQCD predictions and the data in Scenario I is better than that in Scenario II,which can be tested by the forthcoming LHC experiments;(c) the annihilation contributions play an important role for these considered decays.     

B→K0^＊（1430）η（＇） decays in the pQCD approach

Based on the assumption of two-quark structure of the scalar meson K0^＊（1430）, we calculate the CP-averaged branching ratios for B→K0^＊（1430）η（＇） decays in the framework of the perturbative QCD （pQCD） approach here. We perform the evaluations in two scenarios for the scalar meson spectrum. We find that： （a） the pQCD predictions for Br（B→K0^＊（1430）η（＇）） which are about 10^-5 10^-6, basically agree with the data within large theoretical uncertainty; （b） the agreement between the pQCD predictions and the data in Scenario Ⅰ is better than that in Scenario Ⅱ, which can be tested by the forthcoming LHC experiments; （c） the annihilation contributions play an important role for these considered decays.     

B→K_0~*(1430)η~(') decays in the pQCD approach

Based on the assumption of two-quark structure of the scalar meson K*0(1430),we calculate the CP-averaged branching ratios for B→K0*(1430)η(') decays in the framework of the perturbative QCD(pQCD) approach here.We perform the evaluations in two scenarios for the scalar meson spectrum.We find that:(a) the pQCD predictions for Br(B→K*0(1430)η(')) which are about 10-5-10-6,basically agree with the data within large theoretical uncertainty;(b) the agreement between the pQCD predictions and the data in Scenario ...     

PP→π0π0η分波分析理论公式及蒙特卡罗模拟研究

pp^-→π^0π^0 η飞行湮没过程是寻找π^0π^0η系统中的胶球和π^0η系统中的J^pc为1^- 的奇特态粒子的极佳过程,采用相对论张量分波分析方法给出该过程的分波分析理论公式,并对该过程进行了一些蒙特卡罗模拟研究。     

Anomalies in(semi)-leptonic B decays B~±→τ~±ν,B~±→Dτ~±ν and B~±→D~*τ~±ν,and possible resolution with sterile neutrino

The universality of the weak interactions can be tested in semileptonic b→c transitions,and in particular in the ratios R(D~(*)) ≡Γ(B → D(*)τν)/Γ(B → D~(*)lν)(where 1 = μ or e).Due to the recent differences between the experimental measurements of these observables by Ba Bar,Belle and LHCb on the one hand and the Standard Model predicted values on the other hand,we study the predicted ratios R(D~(*))=Γ(B→D~(*)τ+"missing")/Γ(B→D(*)lν)in scenarios with an additional sterile heavy neutrino of mass ～1 Ge V.Further,we evaluate the newly defined ratio R(0)≡Γ(B→τ+"missing")/Γ(B→μν) in such scenarios,in view of the future possibilities of measuring the quantity at Belle-Ⅱ.     

Partial wave analysis ofJ/ψ）→ppπ0 and measurement of J/ψ→ppη,ppη＇

Based on 58 million J/ψ data collected with the BESII detector at the BEPC, Partial Wave Analysis（PWA） is performed on J/ψ→ppπ0. The new excited baryon N（2065） is confirmed. Clear signals for other N＊ states are observed and the corresponding masses, widths and spin-parity are also measured. Processes such as J/ψ→ppη,ppη＇
are also studied and the branching ratios are measured.     

Studies of Bs^0 → η＇η＇ Decays in pQCD Approach

We calculate the CP averaged branching ratios and CP-violating asymmetries for Bs^0 → η＇η＇ and η＇η＇ decays in the perturbative QCD （pQCD） approach here. The pQCD predictions for the C P-averaged branching ratios are Br（Bs^0 → ηη）=（14.2-7.5^＋18.0） ×10^-6,Br（Bs^0 → ηη＇）=（12.4-7.0^＋18.2）×10^-6,and Br（Bs^0 → η＇η＇） =（9.2-4.9^＋15.3）×10^-6, which agree well with those obtained by employing the QCD factorization approach and also be consistent with available experimental upper limits. The gluonic contributions are small in size： less than 7% for Bs →ηηand ηη＇ decays, and around 18% for Bs →η＇η＇ decay. The CP-violating asymmetries for three decays are very small： less than 3% in magnitude.     

不稳定粒子η的衰变分支比R((η→ππγ)/(η→3π))

本文以η→ππγ与η→3π的分支比为示例,讨论了通过对质量作解析延拓,用色散关系处理不稳定粒子衰变的方法,尤其是存在有反常阈的情形。在一定近似下,求得了分支比R((η→ππγ)/(η→3π))≈0.65,与最新实验结果相近。     

Final state interaction in B 0 → J/ψρ0 1

In this research, the hadronic decay of B ⁰ → J/φρ⁰ is analyzed by using the QCD factorization (QCDF) and final state interaction (FSI). The D ^+(*) D ^?(*) for d $\bar d$ and D ^0(*) $\bar D^{0(*)}$ for u $\bar u$ contributions via the exchange of charmed mesons are chosen for the intermediate states. These amplitudes are calculated by using QCDF and used in the absorptive part of the diagrams. The experimental branching ratio of B ⁰ → J/φρ⁰ decay is (2.7 ± 0.4) × 10^?5 and our results according to the QCDF method and FSI are 0.87 × 10^?5 and (0.057–4.18) × 10^?5, respectively.     

τ→π~±2π~0v结构函数的测量

首次对τ→π2π0v衰变的结构函数进行了模型无关的实验测量,并与KS模型、IMR模型和Feindt模型进行了比较,在误差范围内,三种理论模型与实验结果一致．与OPAL组测量的τ→3π±v道的结构函数相比,在0．5＜Q2＜2．75GeV2范围内未发现明显差异．     

Annihilation contribution and B → a 0π, f 0 K decays

We analyze the and B^–,0 → f₀K^–,0 decays and show that a consistent phenomenological picture can be obtained within the factorization approximation. In this approach the O₆ operator provides the dominant contributions to the suppressed channel . An estimate of the annihilation form factor using perturbative QCD indicates that this contribution is not negligible, moreover interference with other penguin contributions includes a free parameter since the phase of the annihilation amplitude is not determined. Assumptions based on SU(2) isospin symmetry provide relations between different B decays involving one scalar and one pseudoscalar meson.     

Semileptonic Decays B＊→ηclυl with QCD Sum Rules

In this article, we calculate the B＊→ηc form-factors with the three-point QCD sum rules, then study the semileptonic decays B＊→ηclυl. The tiny decay widths may be observed experimentally in the future at the LHCb, while the B＊→ηc form-factors can be taken as basic input parameters in other phenomenologieal analysis.     

The decay φ→η″γ

A search for the process e ⁺ e ⁻→φ(1020)→η″(958) γ in the decay channel η″→π ⁺ π ⁻ η, η→γγ was made in an experiment at the VEPP-2M e ⁺ e ⁻ collider with the SND detector. Analysis confirms the occurrence of φ→η″γ decay with probability B(φ→η″ γ)=(6.7 _−2.9 ^+3.4 )×10⁻⁵. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 2, 87–91 (25 January 1999)