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Manuscript Title: Numerical solution of Q**2 evolution equation for the transversity distribution Delta_Tq.
Authors: M. Hirai, S. Kumano, M. Miyama
Program title: H1EVOL
Catalogue identifier: ADHY_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 111(1998)150
Programming language: Fortran.
Computer: AlphaServer 2100 4/200.
Operating system: Open VMS V6.1, SunOS 4.1.3.
Keywords: Particle physics, Elementary, Qcd, Polarized parton Distribution, Transversity Distribution, Chiral-odd structure Function, Q**2 evolution, Numerical solution.
Classification: 11.5.

Nature of problem:
This program solves the DGLAP Q**2 evolution equation with or without next-to-leading-order (NLO) alphas effects for a transversely polarized parton distribution, so called transversity distribution Delta_Tq or chiral-odd structure fuction h1.

Solution method:
The DGLAP integrodifferential equation is solved by dividing the variables x and Q**2 into very small steps. The integrodifferential equation is solved step by step by the Euler method ("brute-force" method) in the variable Q**2 and by the Simpson method in the variable x.

This program is used for calculating the Q**2 evolution of various transversity distributions Delta_Tq(h1). The Q**2 evolution equation is the DGLAP equation. The double precision arithmetic is used. The minimal subtraction (MS) or the modified minimal subtraction (MSbar) scheme is used in the NLO evolution. The NLO evolution is identical in both schemes. A user provides the initial distribution as a subroutine or as a data file. Examples are explained in Section 4. Then, the user inputs seventeen parameters in Section 4.

Running time:
Approximately forty seconds on AlphaServer 2100 4/200 and two and a half minutes on SUN-IPX.