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1.
Hadron molecules     
We discuss a possible interpretation of the open charm mesons D*s0 (2317),D s1 (2460) and the hidden charm mesons X(3872),Y(3940) and Y(4140) as hadron molecules.Using a phenomenological Lagrangian approach we review the strong and radiative decays of the D* s0 (2317) and D s1 (2460) states.The X(3872) is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration.Determing the radiative (γJ/ψ and γψ(2s)) and strong (J/ψ2π and J/ψ3π) decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X(3872).Finally,we give evidence for molecular interpretations of the Y(3940) and Y(4140) related to the observed strong decay modes J/ψ+ω or J/ψ+φ,respectively.  相似文献   

2.
Hadron molecules     
We discuss a possible interpretation of the open charm mesons D*s0 (2317),D s1 (2460) and the hidden charm mesons X(3872),Y(3940) and Y(4140) as hadron molecules.Using a phenomenological Lagrangian approach we review the strong and radiative decays of the D* s0 (2317) and D s1 (2460) states.The X(3872) is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration.Determing the radiative (γJ/ψ and γψ(2s)) and strong (J/ψ2π and J/ψ3π) decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X(3872).Finally,we give evidence for molecular interpretations of the Y(3940) and Y(4140) related to the observed strong decay modes J/ψ+ω or J/ψ+φ,respectively.  相似文献   

3.
The initial single pion emission (ISPE) mechanism is applied to the processes r(5S)→πB(*)B-(*), whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell's measurements; that is, we succeed in reproducing the enhancement structures of Zb(10610) and Zb(10650). Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D*D- and D*D-*.  相似文献   

4.
The positive parity scalar D * s0 (2317) and axial-vector D * s1 (2460) charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D(D s )-meson ground states.The specific masses of these states are obtained as a consequence of the attraction arising from the Weinberg-Tomozawa interaction in the chiral Lagrangian.Chiral corrections to order Q 2 χ are calculated and found to be small.The D * s0 (2317) and D * s1 (2460) mesons decay either strongly into the isospin-violating π 0 D s and π 0 D ? s channels or electromagnetically.We show that the π 0-η and (K^ 0 D ^+-K^ + D^ 0 ) mixings act constructively to generate strong widths of the order of 140 keV and emphasize the sensitivity of this value to the KD component of the states.The one-loop contribution to the radiative decay amplitudes of scalar and axial-vector states is calculated using the electromagnetic Lagrangian to chiral order Q 2 χ .We show the importance of taking into account processes involving light vector mesons explicitly in the dynamics of electromagnetic decays.The radiative width are sensitive to both η D s and KD components,hence providing information complementary to the strong widths on the positive parity D s-meson structure.  相似文献   

5.
We calculate the D s 1 (2536) ^+ decays into D*K channels,including the decay D s 1 (2536) + → D + π-K + through a virtual D*0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement with the recent Belle and BABAR data,being the results sensitive to 1 P 1 and 3 P 1 mixture.  相似文献   

6.
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   

7.
刘翔 《中国物理 C》2009,33(12):1307-1311
In this talk, we firstly overview the experimental status of Nx(1625), which is an enhancement structure observed in K-3. invariant mass spectrum of J/ψ → pK-∧. process. Then we present the result of the decay of Nx(1625) under the two molecular assumptions, i.e. S-wave∧K- and S-wave ∑0K- molecular states. Several experimental suggestions for Nx (1625) are proposed.  相似文献   

8.
肖绪洋 《中国物理 B》2012,21(4):46102-046102
The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the (AgCo)561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt~e structure and chemical ordering of the (AgCo)561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen (CoAg)561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag.  相似文献   

9.
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   

10.
We show the lattice QCD results on the axial charge gAN*-N* of negative parity nucleon resonances, N*(1535) and N*(1650), which are key clues to the chiral structure in baryon sector. The measurements are performed with up and down dynamical quarks employing the renormalization-group improved gauge action at β=1.95 and the O(a) improved clover quark action with the hopping parameters, κ=0.1375, 0.1390 and 0.1400. In order to properly separate signals of N* (1535) and N* (1650), we construct 2 × 2 correlation matrices and diagonalize them. Wraparound contributions in the correlator, which can be another source of signal contaminations, are eliminated by imposing the Dirichlet boundary condition in the temporal direction. We find that the axial charge of N* (1535) takes small values as gAN*N*-O(0.1), whereas that of N* (1650) is about 0.5, which is found independent of quark masses and consistent with the predictions by the naive nonrelativistic quark model.  相似文献   

11.
Apart from the charmful decay channels of Y(4260), the charmless decay channels of Y(4260) also provide us a good platform to study the nature and the decay mechanism of Y(4260). In this paper, we propose to probe the structure of Y(4260) through the charmless decays Y(4260)→VP via intermediate D1D+c.c. meson loops, where V and P stand for light vector and pseudoscalar mesons, respectively. Under the molecule ansatz of Y(4260), the predicted total branching ratio BRVP for all Y(4260)→VP processes are about (0.34-0.23+0.23)% to (0.75-0.52+0.72)% with the cutoff parameter α=2-3. Numerical results show that the intermediate m D1D+c.c. meson loops may be a possible transition mechanism in the Y(4260)→VP decays. These predicted branching ratios are the same order to that of Y(4260)→Zc+(3900)π-, which may be an evidence of D1D molecule and can be examined by the forthcoming BESⅢ data in the near future.  相似文献   

12.
The decay properties of the D and D s mesons are computed in a nonrelativistic phenomenological quark-antiquark potential of the type V (r) =-4 /3 α s /r+ Ar ν with different choices of ν.Numerical method to solve the Schrdinger equation has been used to obtain the spectroscopy of qQ mesons.The numerically obtained radial solutions are employed to obtain the decay constant and leptonic decay widths.It has been observed that predictions of the ground state masses and the decay widths are consistent with other model predictions as well as with the known experimental values.  相似文献   

13.
According to the new K^*(892)^0 and K^*(892)^- masses reported by the BELLE experiment and the K^*(892)^0 mass reported by the FOCUS experiment, mass splitting between neutral and charged K^*(892) becomes very small. This is significantly different from the current world average values given by the Particle Data Group 2008. We find that there are differences between models used to fit the K^*(892) decay invariant mass spectra in different measurements and study the model dependence in the measurement of K^*(892) parameters. We refit the K^*(892)^0 mass spectra of the BELLE and FOCUS experiments with the formula used by BELLE in fitting K^*(892)^- to get new mass and width. After refitting, the K^*(892)^0 mass of the BELLE experiment becomes 1.4 MeV/c^2 larger than the initial value and that of the FOCUS experiment is 1 MeV/c^2 smaller than the initial value. We also fit the spectra of some other experiments to extract the K^* (892) parameters using the BELLE K^* (892)^- parametrization.  相似文献   

14.
We systematically investigate the mass spectra of {Qs}{Q(')s} molecular states in the framework of QCD sum rules. The interpolating currents representing the molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). The masses for molecular states with various {Qs}{Q(')s} configurations are presented. The result 4.36 ± 0.08 Ge V for theDs* Ds0- * molecular state is consistent with the mass 4350+4.6 -5.1± 0.7 MeV of the newly observed X(4350), which could support X(4350) interpreted as a D*D*so molecular state.  相似文献   

15.
Systematic approaches are presented to extract the interfacial potentials from the ab initio adhesive energy of the interface system by using the Chen–M ¨obius inversion method. We focus on the interface structure of the metal(111)/Zn O(0001)in this work. The interfacial potentials of Ag–Zn and Ag–O are obtained. These potentials can be used to solve some problems about Ag/Zn O interfacial structure. Three metastable interfacial structures are investigated in order to check these potentials. Using the interfacial potentials we study the procedure of interface fracture in the Ag/Zn O(0001) interface and discuss the change of the energy, stress, and atomic structures in tensile process. The result indicates that the exact misfit dislocation reduces the total energy and softens the fracture process. Meanwhile, the formation and mobility of the vacancy near the interface are observed.  相似文献   

16.
Employing improved calculations of the decay form factors from light-cone sum rules, we evaluate the invariant mass spectrum, forward-backward asymmetry, and lepton polarizations of the exclusive processes B → K^(*)e+e- in the SM and T2HDM. From the recent measurements of their branching ratios, we find that these processes do provide additional bounds on the new parameters in the model considered here. After the inclusion of the new physics contributions, the large enhancement of FBA, which is unobservably small within the SM and of the lepton polarization at large tan β, may precisely test the SM or reveal new physics in forthcoming accurate experiments.  相似文献   

17.
孙亮   《中国物理 C》2010,34(9):1504-1507
Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e + e  ̄ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K (*) l + l ̄ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K* l + l ̄ decay,we also measure the K* longitudinal polarization fraction and the di-lepton forwardbackward asymmetry.  相似文献   

18.
徐庆君  Z. Was 《中国物理 C》2010,34(6):889-895
PHOTOS Monte Carlo is widely used for simulating QED effects in decay of intermediate particles and resonances. It can be easily connected to other main process generators. In this paper we consider decaying processes γ*→π^+π^-(γ) and K^±→π^+π^-e^±υ(γ) in the framework of Scalar QED. These two processes are interesting not only for the technical aspect of PHOTOS Monte Carlo, but also for precision measurement of αED(Mz), g--2, as well as ππ scattering lengths.  相似文献   

19.
The DK interaction is relevant to the interpretation of the DsJ(2317). We dynamically investigate S-wave DK interactions in the chiral SU(3) quark model by solving the resonating group method equation. The numerical results show an attraction between D and K, which is from boson exchanges between light quarks. However, such an attraction is not strong enough to form a DK molecule. Meanwhile, S partial wave phase shifts of DK elastic scattering are obtained. The case of S-wave D^*K is rather similar to that of DK. To draw a definite conclusion of whether a molecular state exists in DK or the D^*K system, more details of dynamics should be considered in a future study.  相似文献   

20.
We discuss the implications of the recently reported R_K and R_(K*) anomalies, the lepton flavor nonuniversality in the B → Kl~+l~-and B → K~*l~+~l- decay channels. Using two sets of hadronic inputs of form factors, we perform a fit of new physics to the R_K and R_(K*) data, and significant new physics contributions are found. We suggest the study of lepton flavor universality in a number of related rare B,Bs,Bc and Λb decay channels, and in particular we give predictions for the μ-to-e ratios of decay widths with different polarizations of the final state particles, and of the b → dl~+l~- processes, which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in the Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.  相似文献   

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