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1.
By employing the perturbative QCD (pQCD) factorization approach, we calculate the full leading and the partial next-to-leading order (NLO) contributions to the seven B →πη(′) and η(′)η(′) decays. For B^+→ π+η(′) decays, the pQCD predictions for their decay rates agree very well with the data after the inclusion of the small NLO contributions. For neutral decays, the pQCD predictions are also consistent with the experimental upper limits and can be tested by the LHC experiments. The measured value of dir .Acp^dir(π+η)= 19±7% can also be accommodated by the pQCD approach.  相似文献   

2.
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.  相似文献   

3.
We calculate the inclusive decay rates of ηb into charmonium via double c~ pairs for S- and P-wave states ηc, J/ψ and XcJ within the framework of non-relativistic QCD (NRQCD) factorization at leading order in αs. Besides calculating the contributions of the color-singlet channels ηb → cc[2s+1SL^(1)]+cc, the effects of cc pair in the color-octet configurations are also considered. We find that ηb → cc[3S1^(8)] +cc make a small contribution to Br(ηb →J/ψ(ηc)+cc). While in the ηb →XcJ +cc case, the color octet contributions are significant, for they are of the same a 5 order as the color-singlet processes. We predict Br(ηb →J/ψ(ηc)+cc) = 2.99(2.75) × 10^-5 Vc for S-wave states J/ψ and ηc, and Br(ηb → XcJ +cc) = (4.37, 3.40, 2.83) × 10^-5 (for J = 0,1, 2) for P-wave states XcJ. In the end, we also find Br(ηb → cccc) is almost saturated by ηb decay into charmonium in association with cc pair from the point of view of duality.  相似文献   

4.
By employing the perturbative QCD(pQCD) factorization approach, we calculate the new physics contributions to the four B→Kη()decays in the Standard Model(SM) with a fourth generation of fermions(SM4),induced by the loop diagrams involving t quark. Within the considered parameter space of the SM4 we find that:(a) the next-to-leading order(NLO) pQCD predictions for the branching ratios and CP-violating asymmetries in both the SM and SM4 generally agree with the data within one standard deviation;(b) for Br(B→Kη), the inclusion of the fourth generation contributions can improve the agreement between the theoretical predictions and the data effectively;(c) however, for Br(B → Kη) the decrease due to t loops is disfavored by the data; and,(d) the new physics corrections to the CP-violating asymmetries of the considered decays are only about 10%.  相似文献   

5.
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.  相似文献   

6.
In this paper,we calculated the branching ratios and direct CP violation of the four B→Kπ decays with the inclusion of all currently known next-to-leading order(NLO) contributions by employing the perturbative QCD(pQCD) factorization approach.We found that(a) Besides the 10%enhancement from the NLO vertex corrections,the quark-loops and magnetic penguins,the NLO contributions to the form factors can provide an additional~15%enhancement to the branching ratios,and lead to a very good agreement with the data;(b) The NLO pQCD predictions are A_(CP)~(dir)(B~0→K~+π~0)=(-6.5±3.1)%and A_(CP)~(dir)(B~+→K~+π~0)=(2.2±2.0)%,become well consistent with the data due to the inclusion of the NLO contributions.  相似文献   

7.
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 ...  相似文献   

8.
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e+e collider. We measure the branching fraction of radiative decay J/ψ→ηcγ, ηc width and mass. Our preliminary results are: M(ηc) = 2979.4± 1.5 ± 1.9 MeV/c^2, Г(ηc) = 27.8±5.1 ±3.3 MeV, B(Jψ→ηcγ) = (2.34±0.15±0.40)%.  相似文献   

9.
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.  相似文献   

10.
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.  相似文献   

11.
With a 15M J/ψ inclusive Monte Carlo sample, the absolute branching fraction of J/ψ→γη′ from the J/ψ inclusive photon spectrum is measured to be Br(J/ψ→γη′)= (4.68 ± 0.08± 0.27) × 10-3, which is in good agreement with the input value. The J/ψ→γfJ(2220) is also searched for using the same sample. Under our assumptions, the statistical significanees of J/ψ→γfJ(2220) are larger than 7σ.  相似文献   

12.
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.  相似文献   

13.
The study of ρ-ω mixing has mainly focused on vector meson decays with isospin I = 1, namely theρ(ω)→π+π- process. In this paper, we present a study of ρ-ω mixing in ρ(ω)→π+π-π0(I = 0) using a flavor parameterization model for the J/ψ→VP process. By fitting a theoretical framework to PDG data, we obtain the SU(3)-breaking effect parameters sV = 0.03±0.12, sP = 0.17±0.17 and the ρ-ω mixing polarization operatorΠρω =(0.006±0.011) GeV2. New values are found for the branching ratios when the mixing effect is incorporated:Br(J/ψ→ωπ0)=(3.64±0.37)×10-4, Br(J/ψ→ωη)=(1.48±0.17)×10-3, Br(J/ψ→ωη)=(1.55±0.56)×10-4, these are different from the corresponding PDG2012 values by 19%, 15% and 15%, respectively.  相似文献   

14.
We search for the ψ(4S) state in the B~±→ηJ/ψK~± and e~+e~-→ηJ/ψ processes based on the Belle measurements with the assumed mass M =(4230±8) MeV/c~2 and width Γ =(38±12) MeV. No significant signal is observed in the ηJ/ψ mass spectra. The 90% confidence level upper limit on the product branching fraction B(B~±→ψ(4S)K~±)B(ψ(4S)→ηJ/ψ) 6.8×10~(-6) is obtained in the B~±→ηJ/ψK~± decays. By assuming the partial width of ψ(4S)→e~+e~-to be 0.63 ke V, a branching fraction limitB(ψ(4S)→ηJ/ψ) 1.3% is obtained at the 90%confidence level in e~+e~-→ηJ/ψ, which is consistent with the theoretical prediction.  相似文献   

15.
平荣刚   《中国物理 C》2010,34(6):626-631
Using ~ 14 × 10^6 ψ(2S) and ~ 58 × 10^ J/ ψ data collected at BES Ⅱ/BEPC, the branching fraction of ψ(2S)→Ω-Ω^+ is measured with about 5a statistical significance. The A electric dipole and ∧ decay parameter are studied using the decay J/ψ →∧∧→ ppπ^+π^-. Using (106±3)× 10^6 ψ(2S) decays collected at BESⅢ/BEPC Ⅱ, we have obtained some interesting physics results. The branching fractions of XcJ→π^0π^0, ηη are measured with precision improved. The mass and width of he(l^1P1) state, together with the branching fractions of Br(ψ(2S) →π^0hc) and Br(hc →γηc) are the first measurements. Surprisingly, the decays of Xc1→φφ, ωω, and ωφ are firstly observed in BESⅢ data.  相似文献   

16.
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.  相似文献   

17.
We calculate the inclusive decay rates of ηb into charmonium via double c pairs for S-and P-wave states ηc,J/ψ and χcJ within the framework of non-relativistic QCD(NRQCD) factorization at leading order in αs.Besides calculating the contributions of the color-singlet channels ηb→c[2S+1SL(1)]+c,the effects of c pair in the color-octet configurations are also considered.We find that ηb→c[3S1(8)]+c make a small contribution to Br(ηb→J/ψ(ηc)+c).While in the ηb→χcJ+c case,the color octet contributions are significant,for they are of the same αs4vc5 order as the color-singlet processes.We predict Br(ηb→J/ψ(ηc)+c)=2.99(2.75)×10-5 for S-wave states J/ψ and ηc,and Br(ηb→χcJ+c)=(4.37,3.40,2.83)×10-5(for J =0,1,2) for P-wave states χcJ.In the end,we also find Br(ηb→ cc) is almost saturated by ηb decay into charmonium in association with c pair from the point of view of duality.  相似文献   

18.
We calculate the inclusive decay rates of ηb into charmonium via double cc pairs for S- and P-wave states ηc, J/ψ and χcJ within the framework of non-relativistic QCD (NRQCD) factorization at leading order in αs. Besides calculating the contributions of the color-singlet channels ηb→c(c)[2S+1Sl(1)]+c(c), the effects of c(c) pair in the color-octet configurations are also considered. We find that ηb→c(c)[3S1(8)]+c(c) make a small contribution to Br(ηb→J/ψ(ηc)+c(c)). While in ther ηb→χcJ+c(c) case, the color octet contributions are significant, for they are of the same αs4vc5 order as the color-singlet processes. We predict Br(ηb → J/ψ(ηc)+c(c)) = 2.99(2.75) × 10-5 for S-vrave states J/ψ and ηc, and Br(ηb→χcJ +c(c))= (4.37,3.40,2.83)×10-5 (for J = 0,1,2) for P-wave states χcJ. In the end, we also find Br(ηb → c(c)c(c)) is almost saturated by ηb decay into charmonium in association with cc pair from the point of view of duality.  相似文献   

19.
With a 15M J/ψ inclusive Monte Carlo sample, the absolute branching fraction of J/ψ→γ\η' from the J/ψ inclusive photon spectrum is measured to be Br(J/ψ→γ\η')=(4.68±0.08±0.27)×10-3, which is in good agreement with the input value. The J/ψ→γfJ(2220) is also searched for using the same sample. Under our assumptions, the statistical significances of J/ψ→γfJ(2220) are larger than 7\σ.  相似文献   

20.
杨洪勋 《中国物理 C》2009,33(12):1331-1335
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.  相似文献   

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