Pure annihilation type B → K_0~(*±)(1430)K~((*)■) decays in the family non-universal Z’ model

By assuming that the scalar meson K_0~*(1430) belongs to the first excited states or the lowest lying ground states of qq',we study the pure annihilation-type decays B→K_0~*(1430)K~((*)■) in the QCD factorization approach.Within the Standard Model,the branching fractions are of the order of 10~(-8) 10~(-7),which is possible to measure in the ongoing LHCb experiment or forthcoming Belle-II experiment.We also study these decays in the family non-universal Z' model.The results show that if m_Z≈600 GeV(ζ=0.02),both the branching fractions and CP asymmetries of B~0→K_0~+(1430)K~- could be changed remarkably,which provides us with a place for probing the effect of new physics.These results could be used to constrain the parameters of the Z' model.     

Pure annihilation type D→PP(V) decays in the perturbative QCD approach

The annihilation type diagrams are di cult to calculate in any kind of model or method. Encouraged by the successful calculation of pure annihilation type B decays in the perturbative QCD factorization approach, we calculate the pure annihilation type D→PP(V) decays in the perturbative QCD approach based on the k_T factorization. Although the expansion parameter 1/m_D is not very small, our leading order numerical results agree with the existing experimental data for most channels. We expect more accurate observation from experiments, which can help us learn about the dynamics of D meson weak 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 ...     

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→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.     

A test of CPT symmetry in K~0 vs ■~0 →π~+π~-π~0 decays

I show that the CP-violating asymmetry in K0 vs K0 →π+π-π0 decays differs from that in KL →π+π-,KL →π0π0 or the semileptonic KL transitions,if there exists CPT violation in K0-K0 mixing.A delicate measurement of this difference at a super flavor factory(e.g.,the φ factory) will provide us with a robust test of CPT symmetry in the neutral kaon system.     

Constraints on the R-Parity Violating Couplings Using the Newest Measurement of the Decay B_s~0→μ~+μ~-

Recently, the LHCb collaboration reported the first evidence for the decay B0s→μ+μ-. A branching ratio of B(B0s→μ+μ-)=(3.2+1.51.2)×10 9is given. Using the newest data, and together with the most precise predictions of the Standard Model contributions to the decay, we derive the constraints on the combinations of the R-parity violating parameters. Our results are several orders of magnitudes stronger than the constraints in the previous literature. We also update the constraints on the relevant parameters using the upper limit ofB(B0d→μ+μ-).     

Study of scalar meson a_0(980) from B→a_0(980)π decays

In this paper,we calculate the branching ratios and the direct CP-violating asymmetries for decays B0 →a00(980)π0,a0+(980)π-,a0-(980)π+ and B- →a00(980)π-,a0-(980)π0 by employing the perturbative QCD(pQCD) factorization approach at the leading order.We found that(a) the pQCD predictions for the branching ratios are around(0.4-2.8)×10-6,consistent with currently available experimental upper limits;(b) the CP asymmetries of B0 →a00(980)π0 and B- →a0-(980)π0 decays can be large,about(70-80)% for α=100-.     

Study of the CKM angle γ sensitivity using flavor untagged B_s~0→D~((*)0)φ decays

A sensitivity study on the measurement of the CKM angle y from B_S~0→D~((*)0)φ decays is conducted using the D-meson reconstructed in the quasi flavour-specific modes Kπ,K3π,and Kππ~0,as well as CP-eigenstate modes KK and ππ,where the notation D~0 corresponds to a D~0 or D~0 meson.The LHCb experiment is presented as a use case.A statistical uncertainty of approximately 8°-19°can be achieved with the pp collision data collected in the LHCb experiment from 2011 to 2018.The sensitivity to y should be of the order 3°-8° after accumulating 23 fb~(-1) of pp collision data by 2025,whereas it is expected to improve further by 300 fb~(-1) by the second half of the 2030 decade.The accuracy is dependent on the strong parameters r_B~((*)) and δ_B~((*)),which together with γdescribe the interference between the leading amplitudes of the B_S~0→D~((*)0)φ decays.     

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（Bˉ^0 → f0（980） π^0） ～ 2.6×10^-7,Br（Bˉ^0 → f0（980） η） ～ 2.5×10^-7 and Br（Bˉ^0 → f0（980） η ） ～ 6.7×10^-7,which are consistent with both the QCD factorization predictions and the experimental upper limits.     

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.     

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.     

Resonance contributions from χc0 in charmless three-body hadronic B meson decays

Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays begin{document}$ B_{(s)}rightarrow hchi_{c0}rightarrow hpi^+pi^-(K^+K^-) $end{document} with begin{document}$ h=pi, K $end{document}. We compare our predicted branching ratios for the begin{document}$ B_{(s)}rightarrow Kchi_{c0}rightarrow Kpi^+pi^-(K^+K^-) $end{document} decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. However, in the Cabibbo-suppressed decays begin{document}$ B_{(s)}rightarrow hchi_{c0}rightarrow hpi^+pi^-(K^+K^-) $end{document} with begin{document}$ h=bar{K}^0,pi $end{document}, the values of the branching ratios are of the order of begin{document}$ 10^{-7} $end{document} and begin{document}$ 10^{-8} $end{document}. The ratio begin{document}$ R_{chi_{c0}} $end{document} between the decays begin{document}$B^+rightarrow $end{document}begin{document}$ pi^+chi_{c0}rightarrow pi^+pi^+pi^-$end{document} and begin{document}$ B^+rightarrow K^+chi_{c0}rightarrow K^+pi^+pi^- $end{document} and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.     

B → ρ（ω, φ）η（＇） Decays and NLO Contributions in pQCD Approach

By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.     

B→KK衰变中的软胶子修正

应用光维QCD求和规则研究了B→KK衰变的软胶子交换修正,虽然QCD因子化方法已经计算了领头阶的因子化和硬胶子交换的α_s阶辐射修正部分,然而系统地估算所有树图和企鹅图的非因子化软胶子贡献是有价值的,我们的结果表明在B→KK衰变中软胶子效应总是使分支比值减小,约为几个百分点.     

QCD因子化在湮没衰变_(s,d)~0→J/ψγ中的应用

在QCD因子化框架下 ,对可能的辐射湮灭衰变 B0s ,d→J/ψγ进行研究 .在标准模型中 ,相对于简单因子化下领头阶的分支比 ,αs 阶非因子化辐射修正对分支比有显著的量级上的改变 ,这些衰变可用来检验因子化方法 .在理论上 ,B介子稀有辐射衰变对超出标准模型的新物理特别敏感 .作为一个例子 ,我们考虑右手带电流对标准模型中左手流可能的混合效应 ,这个混合对衰变分支比有显著的影响 .     

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.     

B→（J/ψ,η_c）K decays in the perturbative QCD approach

In this paper,we calculated the B →（J/ψ,ηc） K decays in the perturbative QCD（pQCD） factorization approach with the inclusion of the partial next-to-leading order（NLO） contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors：Br（B0 → J/ψK0） = 5.2-＋32..58×10-4,Br（B＋ → J/ψK＋） = 5.6-＋32..79×10-4,Br（B0 →ηcK0） = 5.5-＋22..30 × 10-4,Br（B＋ →ηcK＋） = 5.9-＋22..51 × 10-4.