Measurement of the Neutron (³He) Spin Structure Function at Low Q²: A Connection between the Bjorken and Drell-Hearn-Gerasimov Sum Rules

Author: Jensen, John Steffen

Year: 2001

Degree: Dissertation (Ph.D.)

Advisors: Hughes, Emlyn Willard; Porter, Frank C.

Committee Members: Hughes, Emlyn Willard; Filippone, Bradley W.; Porter, Frank C.; Wise, Mark B.

Option: Physics

DOI: 10.7907/wmxe-ge51

Abstract

The spin dependent cross sections, σT1/2 and σT3/2 , and asymmetries, A∥ and A⊥ for 3He have been measured at the Jefferson Lab's Hall A facility. The inclusive scattering process 3He(e,e)X was performed for initial beam energies ranging from 0.86 to 5.1 GeV, at a scattering angle of 15.5°. Data includes measurements from the quasielastic peak, resonance region, and the deep inelastic regime. An approximation for the extended Gerasimov-Drell-Hearn integral is presented at a 4-momentum transfer Q2 of 0.2-1.0 GeV2.

Also presented are results on the performance of the polarized 3He target. Polarization of 3He was achieved by the process of spin-exchange collisions with optically pumped rubidium vapor. The 3He polarization was monitored using the NMR technique of adiabatic fast passage (AFP). The average target polarization was approximately 35% and was determined to have a systematic uncertainty of roughly ±4% relative.

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