Polarization phenomena by deuteron fragmentation into pions

Abstract:

The fragmentation of deuterons into pions emitted forward in the kinematic region forbidden for free nucleon-nucleon collisions is analyzed. The inclusive relativistic invariant spectrum of pions and the tensor analyzing power T₂₀ are investigated within the framework of an impulse approximation using various deuteron wave functions. The influence of -wave inclusion in the deuteron wave function is also studied. The invariant spectrum is shown to be more sensitive to the amplitude of the NN↦πX process than the tensor analyzing power T₂₀. It is shown that the inclusion of the non-nucleonic degrees of freedom in a deuteron results in a satisfactory description of the data for the inclusive pion spectrum and improves the description of the data about T₂₀. According to the data, T₂₀ has very small positive values, less than 0.2, which contradicts the theoretical calculations ignoring these degrees of freedom.