摘要:

Low‐energy meson‐meson scattering data are a powerful testing ground for quark models. Here, we describe the behaviour at threshold ofS‐wave scattering‐matrix singularities. The majority of the full scattering‐matrix mesonic poles stem from an underlying confinement spectrum. However, the light scalar mesonsK0*(830),a0(980),f0(400–1200), andf0(980) do not, but instead originate in3P0‐barrier semi‐bound states. We show that the behaviour of the corresponding poles is identical at threshold. In passing, the light‐meson sector is given a firm basis. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1570585

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

An outline is given how to formulate a relativistic unitarized constituent quark model of mesons in momentum space, employing harmonic quark confinement. As a first step, the momentum‐space harmonic‐oscillator potential is solved in a relativistically covariant, three‐dimensional quasipotential framework for scalar particles, using the spline technique. Then, an illustrative toy model with the same dynamical equations but now oneqq¯and one meson‐meson channel, coupled to one another through quark exchange describing the3P0mechanism, is solved in closed form on a spline basis. Conclusions are presented on how to generalize the latter to a realistic multichannel quark/meson model. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1570586

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We show that it is necessary to go beyond a single hadron (beyond the quark‐antiquark or three‐quark systems) in order to distinguish the colour structure of the effective quark‐quark interaction and the relevance of 3‐body forces. We critically discuss the proposed models which suggest the dimeson bbu¯d¯ to be bound by ∼ 100 MeV and the ccu¯d¯ dimeson to be unbound. Only experiment can judge. We estimate the probability of producing bbu¯d¯ at LHC by double gluon‐gluon fusion and search for a characteristic decay. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1570587

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The nucleon‐nucleon problem is studied as a six‐quark system in a nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between the quarks [1, 2]. This hyperfine interaction has a long‐range Yukawa‐type part, depending on the mass of the exchanged meson and a short‐range part, mainly responsible for the good description of the baryon spectra. The nucleon‐nucleon phases shifts are calculated using the resonating group method, convenient for treating the interaction between composite particles. The behavior of the phase shifts for the3S1and1S0channels show the presence of a strong repulsive core. We show that the introduction of a scalar &sgr;‐meson exchange [3] and the tensor force [4] associated to the pseudoscalar meson exchange interaction lead to a satisfactory agreement with the experiencal phase shifts. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1570588

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

© 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1570589

出版商:AIP    

年代:1903

数据来源: AIP