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1.
We have studied \(D_s^ + \to K_0^{* + } \bar K^0\) and \(D_s^ + \to \bar K_0^{*0} K^ +\) decays in the factorization of the hadron currents approximation. The spectator model leads the decays have different but negligible branching ratios. We show, however, that the inclusion of annihilation contribution can enhance the branching ratios. We predict that \(B(D_s^ + \to \bar K_0^{*0} K^ + )\) and \(B(D_s^ + \to K_0^{* + } \bar K^0 )\) could be around 2%.  相似文献   

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The joint production of ? mesons andπ ±,π 0,p, \(\bar p\) ,K s 0 andK ± is investigated using a sample of 600,000 inclusive ? meson events obtained in hadron Be interactions with incidentπ ±,p, \(\bar p\) andK ± beams. Evidence is presented for the joint production of ? mesons and strange particles produced with non-strange incident beams. With incidentK ± beam the number of additional strange particles is suppressed. The results are found to be in agreement with the qualitative predictions of a parton fusion model. The comparison with the Lund model for lowp T processes is fair.  相似文献   

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在对Gruneisen系数高温高压下演化特性不作任何假设的前提下,建立了一种不依赖于等温物态方程具体形式,通过Hugoniot实验数据直接确定0 K零压等温体积模量B0K及其对压力的一阶导数B'0K和初始密度ρ0K等0 K物态方程输入参数的方法.通过与实验和理论数据的分析和比较,表明用这一方法确定的B0K和B'0K不仅合理,而且具有很高的精度,特别是B'0K的精度,要优于目前传统超声实验的测量精度.此外,这一方法所确定的ρ0K不仅在Gruneisen物态方程的框架内与相应的室温零压特性参数相适配,而且与低温热膨胀实验数据所确定的近0 K初始密度ρ0E非常吻合.  相似文献   

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We analyze the and B–,0f0K–,0 decays and show that a consistent phenomenological picture can be obtained within the factorization approximation. In this approach the O6 operator provides the dominant contributions to the suppressed channel . An estimate of the annihilation form factor using perturbative QCD indicates that this contribution is not negligible, moreover interference with other penguin contributions includes a free parameter since the phase of the annihilation amplitude is not determined. Assumptions based on SU(2) isospin symmetry provide relations between different B decays involving one scalar and one pseudoscalar meson.  相似文献   

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在对Grtineisen系数高温高压下演化特性不作任何假设的前提下,建立了一种不依赖于等温物态方程具体形式,通过Hugoniot实验数据直接确定0K零压等温体积模量B0K及其对压力的一阶导数B′0k。和初始密度ρ0K等0K物态方程输入参数的方法。通过与实验和理论数据的分析和比较,表明用这一方法确定的.B0K和B′0k不仅合理,而且具有很高的精度,特别是B′0k的精度,要优于目前传统超声实验的测量精度。此外,这一方法所确定的ρ0K不仅在Grtineisen物态方程的框架内与相应的室温零压特性参数相适配,而且与低温热膨胀实验数据所确定的近0K初始密度ρ0E非常吻合。  相似文献   

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在BESⅡ上利用Bhabha,dimu事例确定了BEPC束流对撞中心位置,并以此为初级顶点研究了次级顶点的重建,改进了原有次级顶点重建程序,在此基础上选择J/ψ→k0sk*0→K±ππ+π-事例,测量了K0s的寿命,并利用50MJ/ψ数据测量了K0s的单举质量谱,最后还利用MC研究了K0s质量的1C拟合.  相似文献   

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A number of peculiarities were found in the effective mass spectrum of the ΛK S 0 system in the ranges of 1650–1680, 1740–1750, 1785–1805, 1835–1860, and 1925–1950 MeV/c 2 during the collision of a 10-GeV/c 2 momentum proton with propane. Detailed research of a mass spectrum structure has shown that significant enhancements have been obtained in two effective mass ranges of 1750 and 1795 MeV/c 2. These peaks could be interpreted as possible candidates of two pentaquark states: the N 0 with quark content udsds decaying into ΛK 0 and the Ξ0 resonance with quark content udsds decaying into . The text was submitted by the authors in English.  相似文献   

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We extend the Clauser-Horne formulation of Bell-type inequality for the correlated pair of decaying and oscillating (neutral pseudo-scalar) meson-antimesons, using a few supplementary assumptions. The quantum-mechanical predictions for the B0- \(\bar B^0 \) system do lead to violations of this inequality under certain conditions. Further work is called for to investigate the possibility of dispensing with the supplementary assumptions.  相似文献   

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New experimental results on the coherentK L 0 C K S 0 C regeneration in the momentum range 10p30 GeV/c are presented. For the quantity (f 0¯f 0/k (where f0 and¯f 0 are theKC and¯K 0C forward scattering amplitudes andk is the wave number) we have obtained: arg (f 0¯f 0)/k=–126±14 and ¦(f 0¯f 0/k¦ p –0.62±0.14 These results are well described by a simple Regge pole model including only the (-trajectory exchange in thet-channel with the intercept (0) close to 0.4.Presented at the IV International Symposium on High Energy and Elementary Particle Physics, Warszaw, September 1975.  相似文献   

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《Physics letters. A》2006,357(1):6-11
We find the time evolution of the system of two non-interacting unstable particles, distinguishable as well as identical ones, in arbitrary reference frame having only the Kraus operators governing the evolution of its components in the rest frame. We than calculate in the rigorous way Einstein–Podolsky–Rosen quantum correlation functions for K0K¯0 system in the singlet state taking into account CP-violation and decoherence and show that the results are exactly the same despite the fact we treat kaons as distinguishable or identical particles which means that the statistics of the particles plays no role, at least in considered cases.  相似文献   

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Within the heavy quark limit and the hierarchy approximation λQCD mD mB, we analyze the B → D00 and Bs → D00 decays, which occur purely via annihilation type diagrams. As a rough estimate, we calculate their branching ratios and CP asymmetries in the perturbative QCD (PQCD) approach. The branching ratio of B → D00 is about 3.8×10-5 that is just below the latest experimental upper limit. The branching ratio of Bs → D00 is about 6.8×10-4, which could be measured in LHC-b. From the calculation, it is found that this branching ratio is not sensitive to the weak phase angle γ. In these two decay modes, there exist CP asymmetries because of the interference between weak and strong interaction. However, these asymmetries are too small to be measured easily.  相似文献   

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负绝对温度状态与正绝对温度状态一样客观存在并且同样具有实际意义.本文从S—U关系及其图形出发研究了金属自由电子在T=一OK及T<OK状态下的分布情况且跟T=+OK及T>OK时的自由电子分布进行了类比,继而给出了微观解释.  相似文献   

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Masses of a number of elementary particles are calculated on the basis of the model suggested in [1] with the use of one parameter. In this model, an electron is considered as an electric cloud enclosed inside an elastic lepton shell, electron neutrino ν е is considered as an elastic lepton shell contracted to a minimal size, and muon, pion and kaon are considered as resonators for quanta of virtual neutrinos excited inside the elastic lepton shell. The number and type of these quanta are determined from the decay scheme for μ, π, and K: 2 for the muon (ν е and ), 3 for the pion (ν е , ν μ, and ), and at least 21 for the kaon. The model allows mass ratios approximating the experimental data for these particles to be obtained for the first time, with the ratio of μ and е masses equal to (6πℏс/е 2)2/3 ≅ 188, the ratio of π 0 and μ masses equal to (3/2)2/3, and the ratio of K 0 and π 0 equal masses to 72/3. The calculated e, μ , π 0, and K 0 masses are in the 0.547:105.707:134.963:493.87 (MeV) ratios (normalized by the neutral pion mass). This is in good agreement with the available experimental data. The mass ν е (≅ 0.02 eV) is also estimated in this model, and the variety of K-meson decay schemes is naturally explained as a result of the variety of excited intrinsic neutrino field structures with the same energy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 23–29, January, 2009.  相似文献   

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Evidence is provided for a new resonance in theK s 0 K s 0 π+π? system with a mass of 1.97±0.01 GeV and width 40±20 MeV. It is produced with an inclusive cross section of ~6μb in the beam fragmentation process of 4-prongK + p interactions with at least 2 associatedV 0's at 32 GeV/c and decays dominantly into theK * ± (892)K s 0 π? mode.  相似文献   

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