No abstract

It is shown that a small (5-8) % admixture of the six-quark component in the deuteron wave function which is to be introduced to describe elastic eD-scattering at large transfer momenta changes essentially the behaviour of the polarization tensor T2o and the ratio R of the vector Px to tensor polarization Px~ compared to the models which do not take such admixtures into account. The corresponding experiments are emphasized to be important, which are aimed at testing the predictions of models including sixquark admixtures in the deuteron.

A detailed analysis is made of the pair, p ny-currents, retardation effects and six-quark admixtures to the charge, quadrupole form factors and to the deuteron polarization. It is shown that the elastic eD-scattering cross section allowing for the meson exchange currents can be described by introducing a six-quark admixture with probability 3.5%. It is predicted that the behaviour of the deuteron polarization tensor at q > 4 fm -x essentially depends on 6q-admixture. PACS: 12.35.Ht; 13.75.Cs; 21.10.Ky At present available are experimental data [1, 2] on the structure function A(q 2) in a wide range of transferred momenta q2< 8 (GeV/c) z which allow one to analyse the deuteron fine structure taking into account meson exchange currents (MEC) and quark degrees of freedom in a deuteron. Attempts to explain the behaviour of A (q2) in the nonrelativistic approach using only the representation of the deuteron nucleon structure and various phenomenological NN potentials have shown that in the region of large transferred momenta q2 > 1 (GeV/c) 2 theoretical calculations provide too low values of A(q 2) that differ from the experimental data by an order of magnitude and more at q2 >6 (GeV/c) 2 (see, for instance, papers [3][4][5][6][7]). In this connection the approaches allowing for the relativistic effects [3,7], meson exchange currents [8][9][10][11], deuteron quark structure [4,5,[12][13][14][15][16], electric neutron form factor [3,7,17], etc. were developed (see, for instance, [18,19]). The relativistic effects are considered mainly along two lines. First, the introduction of the relativistic kinematics and construction (or calculation) of the relevant wave function, and second, the inclusion of the meson-exchange contribution. There are various ways of a direct relativization. The method for solving the corresponding quasipotential equations has been developed in detail in paper [3]. It was shown that such relativistic corrections are * Far-Eastern state university, Vladivostok small and decrease the nonrelativistic structure function A (q2) thus increasing the discrepancy with experiment. In paper [7] a similar consideration led to positive corrections but they turned out to be small again in the region q2<8 (GeV/c) 2 and they could not explain the available experimental data. Putting aside the problem of inclusion of meson exchange currents, one should note an attempt to explain the experiment [3,7,17] by introducing a phenomenological electric form factor of a neutron.It has been indicated in [5,12,20] that the behaviour of A(q 2) in the region of large transfer momenta corresponds to the quark counting rules [21,22], which, together with the assumption about the existence of multiquark systems in nuclei (see, e.g., [23][24][25][26][27]), initiated some successful attempts to explain A(q 2) [4][5][6][12][13][14][15][16]. In these papers the probability for a six-quark admixture to exist in a deuteron is within (2-12)%. This is in agreement with the data for the cumulative [23,[28][29][30], deep inelastic [31] ...