Doctor of Philosophy (Ph.D.)
Jefferson Lab experiment E97-103 measured the spin structure function gn2 (x, Q2) from Q 2 = 0.57 to 1.34 GeV2 with a nearly constant x ≈ 0.2. Combining this data with a fit to the world gn1 data, the size of higher twist contributions to gn2 can be extracted using the Wandzura-Wilczek relation. These higher twist contributions result from quark-gluon correlations and are expected to increase as Q2 decreases. This experiment was performed in Hall A with a longitudinally polarized electron beam and a high density polarized 3He gas target. This measurement reduced the error bars on gn2 in this kinematic region by an order of magnitude and is the first definitive non-zero measurement of gn2 in the deep inelastic scattering regime. The experiment also found a greater than two standard deviation difference between the experimental value for gn2 and gWW2 in the three lowest Q2 points. This is the first evidence of higher twist effects in the deep inelastic scattering regime.
© The Author
Kramer, Kevin M., "A search for higher twist effects in the neutron spin structure function" (2003). Dissertations, Theses, and Masters Projects. Paper 1539623429.