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1.
In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0(980)π^0, a0^+ (980)π^-, a0^-(980)π^+ and B^- → a0^0 (980)π^-, a0^- (980)π^0 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 B^0→ a0^0(980)π^0 and B^- → a0^- (980)π^0 decays can be large, about (70-80)% for α= 100°.  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.
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   

4.
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   

5.
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.  相似文献   

6.
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→ao(980)π0 and B-→a0-(980)π0 decays can be large, about (70-80)% for α = 100°.  相似文献   

7.
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-.  相似文献   

8.
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   

9.
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   

10.
In this proceeding, we propose to directly measure the a0^0(980)-f0 (980) mixing in J/ψ→φf0(980)→φa0^0(980) and Xc1→π^0a0^0(980) →π^0f0(980) with the upgraded Beijing Electron Positron Collider(BEPCII) with BESIII detector. We show that a narrow peak of about 8 MeV will be produced by the a0^0(980)-f0(980) mixing, and the predominant feature makes it standing out from the background contributions. The predicted branching ratios for these two reactions are both expected to be about O(10^-6), which is unambiguously accessible with 10^9 J/ψ and 3 × 10^8 Xc1 at BESⅢ.  相似文献   

11.
In this paper, we calculate the branching ratios for B^+→ Ds^+η, B^+→ Ds^+η′, B^+→ Ds^(→)η and B^+ → Ds^+η′ decays by employing the perturbative QCD (pQCD) factorization approach. Under the two kinds of η - η′ mixing schemes, the quark-flavor mixing scheme and the singlet-octet mixing scheme, we find that the calculated branching ratios agree well with the currently available experimental upper limits. We also consider the so called "fDs puzzle", by using two groups of parameters about the Ds^(→) meson decay constants, that are fDs = 241 MeV, fDs^→ = 272 MeV and fDs = 274 MeV, fDs^→ = 312 MeV, to calculate the branching ratios for the considered decays. We find that the results change 30%by using these two different kinds of paramters.  相似文献   

12.
The pure annihilation type decays Dd^0→Фγand Bs→ργ receive only colour suppressed penguin contributions with a very small branching ratio in the standard model. When we include the previously neglected electromagnetic dipole operator, the branching ratios can be enhanced to R(^-Bd^0→Фγ)≈ 1×10^-11 and R(^-Bs→ργ)~(6 - 16) ×10^-10, which are one order magnitude larger than previous study using the QCD factorization approach. The new effect can also give a large contribution, of order 10^-9, to transverse polarization of B→Фρ and B →ωФ, which is comparable to the longitudinal part. These effects can be detected in the LHCb experiment and the super-B factories.  相似文献   

13.
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   

14.
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   

15.
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   

16.
Within the framework of the perturbative quantum chromodynamics(PQCD) approach, we study the charmless two-body decays B → a1(1260)K*, b1(1235)K*. Using the decay constants and the light-cone distribution amplitudes for these mesons derived from the QCD sum rule method, we find the following results.(a) Our predictions for the branching ratios are consistent with the QCD factorization(QCDF) results within errors, but much larger than the naive factorization approach calculation values.(b) We predict that the anomalous polarizations occurring in the decays B→φK*, ρK*also happen in B→a1 K*decays, while they do not happen in B→b1 K*decays. Here the contributions from the annihilation diagrams play an important role in explaining the larger transverse polarizations in the B→a1 K*decays, while they are not sensitive to the polarizations for the B→b1 K*decays.(c) Our predictions for the direct C P-asymmetries agree well with the QCDF results within errors. The decaysˉB0→b1+K*-, B-→b10K*-have larger direct C P-asymmetries, which could be measured by the present LHCb experiment and the forthcoming Super-B experiment.  相似文献   

17.
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   

18.
B^0(Bs)→γvv decays are useful to determining the decay constants fB(fBs) and B(Bs) meson wave function. Using the B meson wave function determined in hadronic B(Bs) decays, we study the uncertainties due to the types of B meson wave functions. We find that the branching ratios are sensitive to the type of wave functions and input parameters, but the energy spectrum is independent. The predicted branching ratios are (0.45-1.04)×10^-9 and (2.14-3.27)×10^-8 for B^0 and Bs decay, respectively.  相似文献   

19.
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   

20.
We apply perturbative QCD to the radiative decays of charmonia J/ψ and χcJ into light mesons. We perform a complete numerical calculation for the quark-gluon loop diagrams involved in these processes. The calculated J/ψ decay branching ratios into p-wave mesons f2(1270) and f1(1285) fit the data well, while that of fo(980) (if treated as an ss meson) is predicted to be 1.6×10^-4, which implies that f0(1710) can not be the ss or (uu+dd)/√2 meson. Decays of p-wave charmonia χcJ→ρ(ω;φ)γ (J = 0, 1, 2) are also studied, and the branching ratio of χc1→ργ is predicted to be 1.4×10^-5, which may be tested by CLEO-c collaboration and BESlg collaboration with future experiments.  相似文献   

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