Theoretical investigation of tensor analyzing powers in deuteron fragmentation into pions

Abstract

A detailed analysis of the fragmentation of tensorially polarized deuterons into pions in the kinematical region forbidden for free nucleon-nucleon collisions is performed. Within the relativistic impulse approximation, the inclusive spectrum of product pions and the tensor analyzing power T20 are explored by using various forms of the deuteron wave function. The effect of the P-wave component of the deuteron wave function on these observables is also investigated. It is shown that the invariant spectrum is more sensitive to the form of the NN → πX invariant amplitude than the tensor analyzing power T20. The inclusion of nonnucleon degrees of freedom in the deuteron makes it possible to reproduce the pion spectrum over the entire kinematical region and improves the description of experimental data on T20. According to present-day experimental data, T20 is positive and very small in magnitude, less than 0.2, which is at odds with the results of theoretical calculations disregarding nonnucleon degrees of freedom.