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In this paper, we calculate the branching ratios of Λb→pK- and pπ- decays in the avor changing Z' model. We nd that the branching ratios for these two decay modes are sensitive to the contributions of the Z' boson. For Λb→pK- decay, if the left-handed couplings are equal to the right-handed couplings, the branching ratio of this decay could match up to the currently experimental data for ξs=0.01 and -52°<φsL<132°, or ξs=0.004 and 0°<φsL<84°; if only the left-handed couplings are considered, it could match up to the experimental data for ξs=0.01 and -10°φsL<138°. And for Λb→pK- decay, if the left-handed and right-handed couplings are equal, the branching ratio of Λb→pK- decay may be consistent with the currently experimental data with ξd=0.05 and -135°φdL<43°, if only the left-handed couplings are considered, it may be consistent with ξd=0.05 and -114°φdL<8°. 相似文献
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本文提出了一个对称性破缺前不仅左、右对称, 而且中微子(或反中微子)与荷电轻子、反轻子的弱作用也相同的SU(3)×U(1)模型. 这一模型无三角反常; 导出了sin2θw≤1/4; 在低能范围内与标准模型一致. 我们反轻子数推广为轻子荷. 证明了只有轻子荷才是严格守恒的, 各代轻子数分别守恒只能近似成立. 夸克不仅带有重子数、电荷, 而且也带有轻子荷. 本模型预言有μR→eR+νeL+νμR, e-+e-→μ-+μ-等现象. 相似文献
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在海拔3220米的实验室里,用磁谱仪动量予选装置和多板云室,对落在0.23m2面积上的单根荷电强子进行了观测.考虑到各种可能的修正以后,得出在10—20 GeV/c之间,荷电强子的负正比为:N-/N+=0.53±0.05.当认为N+只包含有P和π+,N-是π-,而且Nπ+/Nπ-=1时,推算出Nπ-/Np=0.9±0.1.若π-积分谱的形式为j(>p)=Kp-r,估算出在5—20 GeV/c的动量范围,r(?)2.3.本文也对荷电强子的积分流强作了粗略的估计,其结果是:j⊥p+π(>12 GeV/c)=(7.4±0.7)×10-5cm-2·st-1·s-1. 相似文献
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本文提出一种SU(4)⊙SU(2)⊙SU(1)统一模型. 在此模型中, 层子和轻子放于同一个多重态中, 所以它们有耦合, 但这种耦合不会导致质子衰变, 只对高能散射有效应. 此模型预言了有两种中性中间玻色子, 还算得了sin2θw=0.25, 并可使中微子有合理的质量. 相似文献
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We study the effects of the fourth quark generation model in Bs → π-K+ decay. Combining with the up-to-date experimental measurement for B(Bs → π-K+) and Acpdir(Bs → π-K+) by the CDF Collaboration, we derive the new bound of weak phase øbd, which are 0°< øbd <44°, 321°< øbd < 360° and 0°< øbd < 26°, 342°< øbd < 360° for mt'=400 and 600 GeV respectively. In these regions, B(Bs → π-K+) and Acpdir(Bs → π-K+) consist with the current experimental data within errors. 相似文献
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本文引进了sd玻色子的6维无迹算符. 按照类似于文献[1,2]中的方法, 首先用这些算符构成SU6 SO6 SO5 SO3波函数, 然后求出用通常的s+d+算符表达的明显公式. 相似文献
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我们用粒子鉴别系统测量了31.2MeV的α粒子在11,10B核上的(α,t)、(α,d)和(α,p)反应的角分布; 由出射粒子的能谱, 我们分别得到了剩余核处于基态和不同激发态的十个角分布. 从角分布的形状看, 在11B(α,t0)12Cg﹒s, 11B(α,d0)13Cg﹒s, 10B(α,d0)12Cg﹒s, 10B(α,d1)12C1st, 11B(α,p0)14Cg﹒s等反应中均有不同程度的后角上翘; 并且(α,t0)和(α,p0)的后角上翘的同位素效应似乎与(α, α)的反常散射的同位素效应相反. 相似文献
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本文内容包括:(ⅰ)进一步给出SU(2)×U(1)×S3模型的结果S2≈S3≈(ms2)/(mb2);sin δ≤(mumd)/(mcms),并预言b夸克的主要衰变道是b→u+W,b夸克的寿命可能长到10-9秒.(ⅱ)给出类K0-K0系统混合时的精确表达式ρ=错号事例数/对号事例数=(1/2)(|p/q|2+|q/p|2)([Γ2+(Δm)2]2-(γ1γ2)2)/([Γ2+(Δm)2]2+(γ1γ2)2);并给出CP破坏的精确表达式:A=(1-ρ')/(1+ρ')=(IM12Γ12*)/(|M12|2+1/4|Γ12|2),这里ρ′=(负电错号事例数)/(正电错号事例数)。 相似文献
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本文从包括对力、四极对力及四极力的核子-核子有效相互作用出发,按照相互作用玻色子模型(IBM)的Dyson表示,对于(满壳)50(d5/2g7/2s1/2d3/2h11/212中子组态的集体能谱进行了微观计算.我们在有效作用强度较广的取值范围内确定IBM玻色子及IBM哈密顿量的微观结构,并把这样得出的IBM哈密顿量对角化,分析了各有效作用项对能谱结构的影响.结果表明:在适当选择的有效作用强度下计算的振动谱与Cd110的实验结果符合较好.而且,通过调节有效相互作用中各强度参量,能够体现从振动谱到转动谱的过渡趋势. 相似文献
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四态叠加多模叠加态光场|Ψe(4),Ⅲ〉q的等阶N次方Y压缩 总被引:7,自引:1,他引:6
根据量子力学的线性叠加原理,构造了由多模偶相干态与多模虚偶相干态组成的第Ⅲ种四态叠加多模叠加态光场态|Ψe(4),Ⅲ〉q的等阶N次方Y压缩特性.结果发现:1) 当压缩阶数N=4m,(m=1,2,3,…)时,态|Ψe(4),Ⅲ〉q恒处于等阶数N-Y最小测不准态;2) 当压缩阶数N=4m′+2,(m′=0,1,2,…)时,在(θ1-θ2),q,Rj,r1,r2等取不同的组合定值下,态|Ψe(4),Ⅲ〉q可分别呈现出等阶N次方Y压缩效应与"半相干态"效应;3) 当压缩阶数N为奇数时,在(θ1-θ2),q,Rj,r1,r2等取不同的组合定值下,态|Ψe(4),Ⅲ〉q可呈现出等阶N次方Y压缩效应. 相似文献
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We study the fine splitting in the charmomium spectrum in the quark model with the channel coupling effect, including DD, DD*, D*D* and DsDs, DsDs*, Ds*Ds* channels. The interaction for channel coupling is constructed from the current-current Lagrangian related to the color confinement and the one-gluon exchange potentials. By adopting the massive gluon propagator from the lattice calculation in the nonperturbative region, the coupling interaction is further simplified to four-fermion interaction. The numerical calculation still prefers the assignment 1++ of X(3872). 相似文献
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本文借助于SU(3)群生成元四种不同的实现,建立了一个以SU(3)规范群为基础的弱电统一模型,得到W&;#177;粒子和Z粒子的质量以及它们与轻子的相互作用都与Weinberg-Salam模型的结果相同,并且给出sin2θw=1/4。这个模型要求有一个新的守恒量子数——弱奇异数存在,还存在四个重矢量粒子V&;#177;和U±±和一些重费米子以及标量粒子。它们都带有不为零的弱奇异数,都和轻子不直接耦合。它们的存在不影响低能范围内轻子的弱电作用,并且只能在高能下成对产生。它们中最轻的粒子将是稳定粒子。本文还讨论了弱奇异数守恒破坏的可能性及其后果。 相似文献
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本文建议轻子电磁自能通过((δm)/m)=(1/(2π))n-b 与量子数 n 联系起来,其中 b 为待定常数.并建议动量截断值 M 与引力常数 k 和精细结构常数α的联系为 M=(?).得到了带电轻子质量公式(?).利用 e-和μ-质量的实验值和α值作输入,给出计算值 k=(6.67231±0.00026)×10-8 cm3g-lsec-2和mτ=(1782.306±0.078)MeV,与观察值 k=(6.6720±0.0041)×10-8cm3 g-1sec-2和 mτ=(1782-4+3)MeV 很好符合.公式预言第四个带电轻子质量应为 m=(11725.47±0.51)MeV 可以在最近的实验中检验。本文还对所建议的质量公式和结果进行了讨论. 相似文献
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The recent measurements on RK and Rπ imply that there exists a possible violation of the leptonic flavor universality which is one of the cornerstones of the Standard Model. It is suggested that a mixing between sterile and active neutrinos might induce such a violation. In this work we consider the scenarios with one or two sterile neutrinos to explicitly realize the data while the constraints from the available experiments have been taken into account. Moreover, as indicated in literature, the deviation of the real PMNS matrix from the symmetric patterns may be due to a μ-τ asymmetry, therefore the measurements on RD(Ds)eμ=Γ(D(Ds)→ e+νe)/Γ(D(Ds)→ μ+νμ) and RD(Ds)μτ=Γ(D(Ds)→ μ+νμ)/Γ(D(Ds)→ τ+ντ) (and for some other heavy mesons B± and Bc etc.) may shed more light on the physics responsible for the violation of the leptonic flavor universality. The data of BESⅢ are available to test the universality and that of future charm-tau factories will provide more accurate information. In this work, we will discuss RD(Ds)eμ and RD(Ds)μτ in detail and also briefly consider the cases for B± and Bc. 相似文献
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本文提出的SU(6)大统一模型, 能容纳现代(V-A)耦合的普通费米子和现代(V+A)耦合的异常费米子. 通过引进一种分立对称性, 使得SU(6)通过Higgs机制自发破缺时, 费米子能得到低质量. 本文还做到了利用简单的Higgs场及其真空期望值, 使异常费米子的质量比普通费米子的质量重. 得到的sin2θw在大统一点的值为3/8. 相似文献
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The centrality dependence of transverse momentum spectra for identified hadrons at midrapidity in Au+Au collisions at √sNN= 200GeV is systematically studied in a quark combination model. The pT spectra of π±, K±, p(p) and Λ(Λ) in different centrality bins and the nuclear modification factors (RCP) for these hadrons are calculated. The centrality dependence of the average collective transverse velocity 〈β(r)〉 for the hot and dense quark matter is obtained in Au+Au collisions, and it is applied to a relative smaller Cu+Cu collision system. The centrality dependence of pT spectra and the RCP for π0, Ks0 and Λ in Cu+Cu collisions at √sNN= 200GeV are well described. The results show that 〈β(r)〉 is only a function of the number of participants Npart and it is independent of the collision system. 相似文献