Mass and angular distributions of charged dihadron production.

Abstract

Experiment 711, conducted at Fermilab, provided a unique handle towards understanding valence quark scattering by studying pairs of single, charged, high-transverse momentum hadrons produced in collisions of 800 GeV/c protons on fixed metal targets. The apparatus consisted of a double-arm spectrometer, calorimetrically triggered, with high momentum resolution and a large angular acceptance for all charge states of particle pairs. The experiment was designed to select those hadron pairs that carried most of the momentum and energy of the underlying scattered quarks and gluons. The charge of such "leading" hadrons are correlated with the charge of the parent quark. Quantum Chromodynamics (QCD) assumes that the scattering behavior of quarks is independent of their charge, or "flavour"; Experiment 711 could test this assumption. This dissertation describes the analysis of the mass and angular distributions of hadron pair production for three separate charge states: $+-$, ++ and $- -$. The angular distributions are found to deviate from theory assumptions for flavour symmetry. Also, the mass cross sections indicate ratios of positive to negative hard-scattered particles that are larger than expected from theory. These results could warrant reconsideration of the assumptions and approximations currently made in leading-order QCD calculations.