Inclusive π0 electroproduction in the deep inelastic region

Abstract

Using 20.5 GeV electrons on protons, we measured inclusive π 0's (of transverse momentum, p T, from 0 to 1.4 GeV/ c) produced by virtual photons of energy, ν, from 4 to 16.5 GeV and four-momentum squared, q 2, from −1.8 to −8.5 (GeV/ c) 2. Comparing with charged pion data, we find σ π0 = 1 2 (σ π + + σ π − ) , supporting the quark model. Photon knockout of a quark is favored as the interpretation of these data because of scaling in z = E π / ν and similarity in z-dependence of other pion production data. Consistent with this interpretation are the dependence of 〈 p T〉 on q 2, the azimuthal dependence, and fits to the constituent interchange model. We also observe a possible p T −4 dependence at large | q 2| over a limited p T range.