Enhanced nonperturbative effects in jet distributions

We consider the triple differential distribution dGamma/dE(J)dm(J)(2)dOmega(J) for two-jet events at center of mass energy M, smeared over the end-point region m(J)(2)<<M-2, \2E(J)-M\similar toDelta, Lambda(QCD)<<Delta<<M. The leading nonperturbative correction, suppressed by Lambda(QCD)/Delta, is given by the matrix element of a single operator. A similar analysis is performed for three-jet events, and the generalization to any number of jets is discussed. At order Lambda(QCD)/Delta, nonperturbative effects in four or more jet events are completely determined in terms of two matrix elements which can be measured in two- and three-jet events.