Quark Spin in the Nucleon

Tamar Didberdze
Ph.D. Candidate
Idaho State University

Semi-inclusive deep inelastic scattering (SIDIS) experiments may be used to identify the flavor of the quark which participates in the scattering process. Semi-inclusive scattering identifies an electron scattering experiment in which the scattered electron and one hadron are detected in the final state. Experiments at Jefferson Lab have used longitudinally polarized electron beam to probe longitudinally polarized Hydrogen (15NH3) and Deuterium (15ND3) targets for an investigation of the quark's contribution to the properties of a nucleon. This talk will report on the measurements made using the CEBAF Large Acceptance Spectrometer (CLAS) at Thomas Jefferson National Laboratory. The incident electron's energy ranged between 1.6 GeV to 5.7 GeV and covered a kinematic region where the struck quark carries at least 30% of the nucleons total momentum (xb > 0.3). The electrons scatter mostly from valence quarks in this kinematic region allowing measurements which are less sensitive to the ocean of quark antiquark pairs that are also inside a nucleon.