共查询到20条相似文献,搜索用时 0 毫秒
1.
Based. On the effective Hamiltonian with the generalized factorization approach, we calculate the branchingratios and CP asymmetries of B → VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the consideredparameter space we find that: (a) for the penguin-dominated B → K* φ and K*0 φ decays, the new physics enhancementsto the branching ratios are around 40%; (b) the measured branching ratios of B →K* φ and K*0φ decays prefer therange of 3 Neffc 5; (c) the SM and TC2 model predictions for the branching ratio B(B →ρ ρ0) are only about halfof the Belle‘s measurement; and (d) for most B → VV decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of mπ and Neffc. 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.
4.
用微扰QCD对B(s) →Фρ 衰变进行了研究,考虑了因子化和非因子化图的贡献,得出了B(s) →Фρ 衰变的分支比以及纵向极化衰变、横向极化衰变之比,所得到的结果与现在的实验数据吻合. 相似文献
5.
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. 相似文献
6.
PINGRong-Gang JIANGHuan-Qing 《理论物理通讯》2003,40(2):183-187
7.
By employing the QCD factorization approach for the exclusive B→Vу decays, we study the exclusive decay B→K^*у in the top-quark two-Higgs-doublet mode/(T2HDM). Within the considered parameter space, we find the following conclusions (a) A hght charged-Higgs boson with a mass about 200 GeV is clearly excluded by the date of B→K^*у decay, and this lower limit is comparable with that from the inclusive B→X8*у decay; (b) The theoretical predictions for CP asymmetry of B→K^*у in the T2HDM is always less than 1% in size; and (c) The isospin symmetry breaking for B→K^*у decay in the SM and T2HDM considered here is around 6% in size and well consistent with the data and the general expectations. 相似文献
8.
XIAO Zhen-Jun LI Feng-Ying ZOU Wen-Jun 《理论物理通讯》2006,46(4):687-696
In this paper, we study the upper bounds on the mass insertion parameters (δAB^q)ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l+l- decay can help us to improve the upper bounds on the mass insertions parameters (δAB^u,d)3j,i3 Some regions allowed by the data of Br(B→ X8γ) are excluded by the requirement of an SM-like C7γ (rnb) imposedby the data of Br(B→ X8γ, X8l+l- ). 相似文献
9.
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
10.
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
11.
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
12.
XINGLi-Rong MAWen-Gain ZHANGRen-You SUNYah-Bin HOUHong-Sheng 《理论物理通讯》2003,40(2):171-182
We investigate the effects from complex parameters on the branching ratio (BR) of the flavor changing rare decay t→ch^0 contributed by the electroweak interactions in the framework of the minimal supersymmetric standard model with complex parameters. We study the dependence of the BR on the possible relevant additional parameter swhich could be the originalsources inducing CP-violation, i.e., the complex phase angles φμ and φAb in squark and chargino sectors and δ13 appearing in Cabibbo-Kobayashi-Maskawa matrix. We find that these parameters influence the BR obviously and the effects induced by φμ and φAb are much larger than by δ13. With the different chosen values of the complex parameters, the BR is in the range between 10^-10 and 10^-8, depending mainly on the phase angles of the higgsino mass parameter μ and the trilinear coupling Ab. 相似文献
13.
In the framework of topcolor-assisted technicolor model we calculate the contributions from the preudo Goldstone bosons and new gauge bosons to e^ e^-→ttk.We find that for reasonable ranges of the parameters,the preudo Goldstone bosons afford dominate contribution,the correction arising from new gauge bosons is negligibly small,the maximum of the relative corrections is-10% with the center-of-mass energy √s=500GeV;whereas in the case of √s=1500 GeV,the relative corrections could be up to 16%.Thus large new physics might be observable at the experiments of next-generation linear colliders. 相似文献
14.
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
15.
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
16.
通过构造适当的关联函数,计算B→π跃迁形状因子f+Bπ(q2),~fBπ(q2)和标量形状因子f0(q2),从而就能研究轻子质量对B0→π-l+~vl(l=e,μ,τ)衰变过程的影响.首次分别计算B0→π-e+~ve,B0→π-μ+~vμ,B0→π-τ+~vτ衰变过程的分支比,并发现轻子质量me,mμ可以忽略,但重轻子质量mτ不能忽略,它对分支比计算有一定的贡献.把计算结果与最近的实验数据进行比较,发现理论结果与实验数据基本符合. 相似文献
17.
It is noted that the rescattering and annihilation effects are significant in the penguin-dominant B→ VV decays. In this work, we suggest to use a unique operator at the quark level to describe all the rescattering and the penguin-induced annihilation effects in B→ φK^*, and the coefficient of the operator depends on the polarizations of the produced mesons. By the flavour SU(3) symmetry, we apply the same scenario to all the penguin-dominant B0190 VV modes. 相似文献
18.
In this paper, we calculated the new physics contribution to theoretically very clean rare decay
B→Xsνν
in the general two-Higgs-doublet model (model III). Within the considered parameter space, we found that
(a) the new physics contribution can provide one to two orders of enhancement to the branching ratio
B(B→Xsνν) and can saturate the experimental bound
on B(B→Xsνν) in some regions of the parameter space; (b) besides the CLEO data of B→Xsγ, the ALEPH upper
limit on B(B→Xsνν) also leads to further constraint on the size of the Yukawa coupling λtt: λtt< 6.4 for
λbb=2.7 and
mH+=200 GeV. 相似文献
19.