Nuclear Physics B148 (1979) 499-512 © North-Holland Publishing Company QCD EFFECTS IN SEMI-INCLUSIVE NEUTRINO PROCESSES A. MI~NDEZ * and A. RAYCHAUDHURI Department of Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK V.J. STENGER ** Department of Nuclear Physics, Keble Road, Oxford OX1 3RH, UK Received 18 August 1978 We present quantitative predictions for effects in semi-inclusive deep inelastic neu- trino scattering which result from first-order QCD calculations. These are done for finite energies and reasonable kinematic cuts to allow their direct comparison with the data when they become available. Non-perturbative effects arising from long-range confine- ment forces are estimated. We show that a reliable quantity, from both theoretical and experimental points of view, for testing QCD in these processes is the mean square mo- mentum component normal to the leptonic plane. 1. Introduction Quantum chromodynamics (QCD) [ 1], the theory of strong interactions obtained by gauging the colour degree of freedom, has a number of attractive features. It is a gauge theory which, aside from its elegance, may provide us with a step towards a superunification with the weak, the electromagnetic and possibly the gravitational interactions. It naturally incorporates the colour degree of freedom which is needed to justify, among other things, the symmetric quark model for baryons, the rate of 7r ° -~ 27, etc. The asymptotic freedom of the theory allows short-distance calcula- tions to be made perturbatively with essentially one free parameter, the effective coupling constant as(Q2), since in the high-energy regime the masses can be neglected Of course, the question of confinement and long-range behaviour in QCD is yet to be settled. Nevertheless, the consensus at this time seems to be that it is possible to make definite predictions from short-range calculations which survive these non-per- * On leave from Departament de Ffsica Tebrica, Universitat Autbnoma de Barcelona, Bellaterra (Barcelona) Spain. ** Permanent address: Department of Physics and Astronomy, University of Hawaii, Honolulu, HI 96822, USA. 499