Table of Contents
ISRN High Energy Physics
Volume 2012, Article ID 943871, 22 pages
Research Article

Spin-Dependent Coupled Altarelli-Parisi Equations in the NLO and the Method of Successive Approximations

1Department of Physics, Goalpara College, Assam, Goalpara 783101, India
2Department of Physics, Gauhati University, Assam, Guwahati 781014, India

Received 28 April 2012; Accepted 28 May 2012

Academic Editors: F. R. Joaquim, S. Oh, and S. Paganis

Copyright © 2012 Ranjit Choudhury and D. K. Choudhury. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The coupled Altarelli-Parisi (AP) equations for polarized singlet quark distribution and polarized gluon distribution, when considered in the small 𝑥 limit of the next to leading order (NLO) splitting functions, reduce to a system of two first order linear nonhomogeneous integrodifferential equations. We have applied the method of successive approximations to obtain the solutions of these equations. We have applied the same method to obtain the approximate analytic expressions for spin-dependent quark distribution functions with individual flavour and polarized structure functions for nucleon.