Single-Pion Production in pp Collisions at =.95 GeV/c (I)

Abstract

The single-pion production reactions $pp\to d{\pi }^{+}$, $pp\to np{\pi }^{+}$ and $pp\to pp{\pi }^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p\approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The implementation of a central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements. Thus all pion production channels were recorded with 1-4 overconstraints. The total and differential cross sections obtained are compared to previous data and theoretical calculations. Main emphasis is put on the discussion of the $pp{\pi }^0$ channel, where we obtain angular distributions different from previous experimental results, however, partly in good agreement with recent phenomenological and theoretical predictions. In particular we observe very large anisotropies for the ${\pi }^0$ angular distributions in the kinematical region of small relative proton momenta revealing there a dominance of proton spinflip transitions associated with ${\pi }^0$ $s$- and $d$-partial waves and emphasizing the important role of ${\pi }^0$ d-waves.

Cited by in corpus (7)

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