Universality of Urbaryon Rearrangement Amplitudes

Abstract

The concept of universality of urbaryon rearrangement amplitudes is introduced, in which the amplitudes of the same type of urbaryon rearrangement for meson-meson, meson-baryon and baryon- (anti) baryon scattering are described as common with each other and the ampli­ tudes of each type are counted even in the presence of the U (6) symmetry breaking, i.e., not pure f-type coupling. Relations for helicity non-flip and flip amplitudes are obtained on the basis of the concept of universality. Above all, it should be noticed that the following results are derived: (i) The relations which comprise the Johnson-Treiman relations and the Freund relations as special cases are obtained and in good agreement with experiments if one takes D/F ratio of helicity non-flip part as F+ =f+/ Cf+ +d+) =1.5. (ii) Universality relations for t-channel iso-scalar part in helicity non-flip and flip amplitudes hold independ­ ently of D/F ratios. (iii) Universality relations for t-channel iso-vector part depend on D/F ratios. (iv) The experimental ratio of polarizations for K+p-elastic scattering to that for pp­ one can be explained reasonably. These results give support to the view that the countable nature of constituent urbaryons reflects on the scattering amplitudes for hadronic reactions. Furthermore, the validity of the universality of urbaryon rearrangement amplitudes suggests that urbaryon rearrangement interaction shares a coupling strength independent of the num­ ber of spectator urbaryons (the universality of urbaryon rearrangement interaction). From the viewpoint of the urbaryon rearrangement (hereafter referred to as UR) it has been found that various characteristic features of hadronic reactions could be interpreted as a consequence of several properties of each UR amplitude. Presumptive evidence in support of the composite model of hadrons and UR model seems to be exhibited in the examination of hadronic reactions in terms of UR. 1 l~s) Especially the validity of the additivity of UR amplitudes seems to be closely related to existence of urbaryon and its dynamics. In view of the elucidation of dynamical properties of urbaryon, it is an interesting problem to ascertain more definitely whether the countable nature of constituent urbaryon reflects on the scattering amplitudes of hadronic reactions. The quark counting 7l in 1965 has been one of the first attempts on the above problem. In this model, however, the scattering amplitudes have not been classified according to the UR diagrams contributing to each process, and furthermore the countable nature of constituent urbaryons is indelibly associated with pure f-type coupling for baryon vertex which is also required by U(6) symmetry. As a result of quark count­ ing, for example, the following relations for total cross sections of high energy meson-baryon and baryon- (anti) baryon scattering have been obtained: