Fragmentation Functions In Semi-inclusive Deep Inelastic Scattering

A quanitative understanding of the quark propagation and hadron formation processes in nuclear medium would greatly benefit the study of quark-gluon plasma and its evolution in space-time.Hadron production in semi-inclusive deep inelastic scattering of leptons from nuclei is an ideal tool to understand the parton propagation and hadronization processes in cold nuclear matter.In the semi-inclusive deep inelastic scattering,a virtual photon from the incident lepton is absorbed by a quark within a nucleus,the colored quark propagates over some distance through the nuclear medium,the existence of a degree of energy loss caused by multiple collision and soft gluon bremsstrahlung.In-depth study of quark propagation and hadronization processes in cold nuclear can help us to understand the quark energy loss effect of the outgoing quark.In this thesis,we study the dependence of the gluon transport coefficient on the parton fragmentation functions by means of the experimental data which picked out from the HERMES experimental results.Within three sets of fragmentation functions of HKNS?KRE and DSS,considering the quenching weight,the ratio of the number of hadrons production on the target of nucleus to the number of deuteron target was calculated and compared with the experimental results.We find that the transport coefficient?q = 0.29 ? 0.03GeV2 / fm both for HKNS and KRE fragmentation functions,and the transport coefficient?q = 0.34 ? 0.03GeV2/fm for DSS fragmentation function.In the range of 1?,the energy loss of the outgoing quark has no obvious dependence on the parton fragmentation functions.