Measurement Of Single Target Spin Asymmetry In Semi-inclusive Deeply Inelastic Scattering Of6Gev Electron On A Polarized~3He Target

In the exploration of the nucleon structure, the physicists cannot get a satisfying answer of the original nuclear spin for a long time. The traditional theory is mainly focused on the contribution of parton helicity to the spin of nucleon. But in leading twist the Transversity distribution can also show some information about the spin of nucleon. The Transversity is defined as the transverse spin distribution of the quark in a transversely polarized nucleon and is chirally odd. Being different from helicity, in leading twist the Transversity does not have gluon contribution, hence shows a significantly different QCD evolution from the helicity. In the traditional inclusive deeply inelastic scattering experiment, the transversely polarized effect of the nucleon is largely suppressed due to the odd chiral. But in the semi-inclusive deeply inelastic scattering, it can be accessed by a chirally-odd fragmentation function.This thesis was based on the research of the Transversity experiment (E06-010). which was taken from2008to2009in Thomas Jeffereson National Lab, US. Com-pared with other experiments in the world, this experiment was the first measurement of the single spin asymmetry on the polarized neutron target, hence largely enriched the understanding of the transversely polarized effect of nucleon. With the5.89GeV electron beam, during the3-month beam time we got n?(e, e'π-)X and n?(e, eπ'+)X scattering data in the kinematic region of0.19<x<0.34,1.77<Q2<2.73(GcV2). This thesis extensively summarized the experimental studies related to the polarized helium-3target in the experiment. By these studies, for the first time we made the3He polarized in any azimuthal direction, successfully pumped the polar-ization in to60%with10atm pressure and at the same time also broke the world record of the polarized luminosity kept before. What is more, based on the results from other collaborators, the single spin asymmetry induced by the Pretzelosity par- ton distribution function were extracted, according to the different azimuthal angl modulation. Although the result is limited by the statistical uncertainty and car only give an up limit of the theory, in next few years this work will be the only resul on neutron.