Measurement of inclusive production of neutral pions at high transverse momentum

Measurement of inclusive production at high transverse momentum (P/sub perpendicular to/) of neutral pions (π0) from protons by beams of protons (p), kaons (K), pions (π), and antiprotons (anti p) is reported. The experiment used the Fermilab M2 beam line. Projectile with momenta of 100, 200, and 300 GeV/c struck a liquid hydrogen target. The data include center-of-mass (cm) production angles of the π0 between 2 and 1150 for P/sub perpendicular to/) greater than 1 GeV/c. A pair of differential Cerenkov counters distinguished the types of beam particles. The photon γ detector of a lead and scintillator sandwich measured both photons from the π0 → 2γ decay and enabled a reconstruction of the π0 kinematics. The measurements show several remarkable features distinguishing the production rates for these different beams, including a forward peak in the cm for π0 production at high P/sub perpendicular to/ in pp than in πp or Kp collisions. A simple parametrization accurately represents the data over most of their range, showing approximate scaling in the radial variable x/sub R/ = 2P/√s (in the cm). Several parton models are compared with the data. A heuristic picture in terms of the quark constituents of the interacting hadrons accounts for many features of the data in an intuitive way