Q2 evolution of multihadron fragmentation functions

In order to characterize jet structure more completely than is possible with the single-hadron fragmentation functions of partons, we deduce the evolution (in Q2) equations for the fragmentation functions of a parton to fragment into an arbitrary number N of hadrons. The solution to the evolution equations is explicitly displayed in terms of multiple moments for the N-hadron fragmentation functions. Our procedure is simpler than using the rules of the jet calculus. We also show how the Q2 dependence of these fragmentation functions can be understood in a recursive cascade-model framework in which both the momentum and the amount by which a parton is off its energy shell (as measured by Q2) are reduced at each branching step during jet formation. This reformulation suggests an alternative way for solving the evolution equations in which moment inversion is not required