Hard Core of the Nuclear Force and Many Fermion Nonlocal Structure of Baryons and Mesons

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It is shown that the " hard core" of the nuclear force at relatively low energies can be regarded as the repulsive force originating from the many fermion structure of nucleon and the exclusion principle. There it is of vital importance that the "baryon" should be a composite particle composed of three urbaryons (not including any antiurbaryon) in a tightly bound state, and that the degree of freedom for a baryon corresponding to three fermions should not be reducible. Along this line of thought, it would be inevitable to accept the hypothesis that the observed particles have the configurations of the ttt type for baryons and of the tt type for mesons, within the framework of the trilocal and bilocal fields with the nonlocal actions. Critical experiments are so proposed as to judge some important predictions obtained from the model. The work is motivated by the recent results of the Japanese nuclear force group that the hard core of the nuclear force has a tail of not the Yukawa shape but the Gaussian shape, and that the hard core of the Gaussian shape is never ascribed to any particle exchange force. Firstly it is verified that the ordinary virtual cloud of a nucleon including nucleonantinucleon pairs gives us no exclusion repulsions, that is, no hard cores. Even with any other structure rather than the virtual cloud, the hard core does not appear if one nucleon state contains a one fermion-state or a one fermion plus bosons-state as its partial amplitude. On the basis of the similar arguments, it is also shown that the conventional local field theory-including the "bootstrap theory" or "Z=0 theory" ----should be excluded. In order that the hard core of the nuclear force, observed in ^<1>S state of two proton system at the relative low energies, can be interpreted as the exclusion repulsion, it is indispensably necessary to accept the hypothesis that each baryon is composed of three urbaryons (each being subject to the exclusion principle as an ordinary fermion), and the requirements that (i) an observed proton is descrived only by the configuration including two identical urbaryons in ^<1>S state and (ii) the degree of freedom of three fermions for a proton is never reduced to the degree corresponding to one fermion or one fermion plus bosons. Most of the models, containing an antiurbaryon as a component of the configuration for a baryon, should be excuded by the first requirement. It seems that only the possibility consistent with the existence of the hard core is given by such a three urbaryon model, not including antiurbaryon for a baryon, as Gell-Mann and Zweig's. It is, however, emphasized that their model does not give the hard core unless the above requirements are fulfilled, that is, that the essential origin of the hard core is not in Gell-Mann and Zweig's scheme but in the present scheme satisfying the above requirements. Owing to the second requirement, the present model sould describe a baryon by a trilocal field of the ttt-type and a meson by a bilocal field of the tt-type. The nonlocal fields should be regarded as a representation of the essential compositeness of baryons and mesons. It is also suggested that the model can be so desinged, by introducing some kind of the nonlocal action into the trilocal and bilocal fields, as to prevent the occurrence of the curious particles with the fractional charge, the trilocal field prepares a substantial ground to introduce the SU(3) symmetry. The present model allows us to make some important predictions as to the appearance of the hard core in S wave force between the various pairs of observed particles as follows: The hard core appears in NN, I=(3/2)_<π>N, I=1KN, NΛ, NΣ, I=1 NΞ, etc. and does not appear in B^^-B, I=(1/2)_<π>N, I=0KN, K^^-N, ππ, I=0 NΞ, etc. It is well known that elastic scattering experiments are consistent with the above results for NN, _<π>N, KN and ππ. It is highly desired to investigate as to whether t
1965-01-25

Hard Core of the Nuclear Force and Many Fermion Nonlocal Structure of Baryons and Mesons

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