Numerical solution of Q2 evolution equation for the transversity distribution ΔTq

We investigate a numerical solution of the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) Q(2) evolution equation for the transversity distribution Delta(T)q or the structure function h(1). The leading-order (LO) and next-to-leading-order (NLO) evolution equations are studied. The renormalization scheme is MS or <M(S)over bar> in the NLO case. Dividing the variables x and Q(2) into small steps, we solve the integrodifferential equation by the Euler method in the variable Q(2) and by the Simpson method in the variable x. Numerical results indicate that accuracy is better than 1% in the region 10(-5) < x < 0.8 if more than fifty Q(2) steps and more than five hundred x steps are taken. We provide a FORTRAN program for the Q(2) evolution and devolution of the transversity distribution Delta(T)q or h(1). Using the program, we show the LO and NLO evolution results of the valence-quark distribution Delta(T)u(upsilon) + Delta(T)d(upsilon), the singlet distribution Sigma(i)(Delta(T)q(i) + Delta T (q) over bar(i)), and the flavor asymmetric distribution Delta(T)(u) over bar - Delta(T)(d) over bar. They are also compared with the longitudinal evolution results. (C) 1998 Elsevier Science B.V.