From Partons to Constituent Quarks: A study of Hadron structure functions

Abstract

This thesis is a study of the processes such as Deep Inelastic Scattering(DIS), and Drell-Yann(DY)in general, which are excellant tools to understand the structure of Hadrons and acting as test grounds for Predictions of Quantum Chromo Dynamics(QCD). The products of currents appearing in the hadronic tensor can also be expressed using Wilson's Operator Product Expansion(OPE) in terms of local operator matrix elements(OME) evaluated between hadron states with perturbatively calculable coefficient functions. Proper interpretation of this OME sheds light on the structure of the Hadron. Further 'Factorization Method', the field theoretical version of the Parton Model, is an elegant method to analyse high energy hadronic processes. This is analogous to OPE approach and it serves as a link between conventional OPE and Parton Model. This thesis is concerned with analysing various hadronic processes and the corresponding structure functions using OPE, parton model and factorization method, and focusing mainly on polarised processes. The concept of structure functions of hadrons in strong interaction physics, is explained in brief.

Both perturbative and non-perturbative aspects of hadronic processes are studied. The quark and gluonic contributions to spin dependent structure functions appearing in week DIS and to the polarized Drell-Yan function in polarized DY process are perturbatively calculated using both parton model and factorization method. Current algebra techniques are used to analyse the operator matrix elements appearing in the first moment of the structure function g1 (x, Q2).