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Title Measurements of the Double-Spin Asymmetry A1 on Helium-3: Toward a Precise Measurement of the Neutron A1
Authors Diana Parno
JLAB number JLAB-PHY-11-1565
LANL number (None)
Other number DOE/ER/40150-4976
Document Type(s) (Thesis) 
Supported by U.S. Naval Research: No
Supported by Jefferson Lab LDRD Funding: No
A PHD thesis
Advisor(s) :
   Gregg Franklin (CMU)
Publication Abstract: The spin structure of protons and neutrons has been an open question for nearly twenty- ve years, after surprising experimental results disproved the simple model in which valence quarks were responsible for nearly 100% of the nucleon spin. Diverse theoretical approaches have been brought to bear on the problem, but a shortage of precise data { especially on neutron spin structure { has prevented a thorough understanding. Experiment E06-014, conducted in Hall A of Je fferson Laboratory in 2009, presented an opportunity to add to the world data set for the neutron in the poorly covered valence-quark region. Je fferson Laboratory's highly polarized electron beam, combined with Hall A's facilities for a high-density, highly polarized 3He target, allowed a high-luminosity double-polarized experiment, while the large acceptance of the BigBite spectrometer gave coverage over a wide kinematic range: 0:15 < x < 0:95. In this work, we present the analysis of a portion of the E06-014 data, measured with an incident beam energy of 4.74 GeV and spanning 1:5 < Q2 < 5:5 (GeV/c)2. From these data, we extract the longitudinal asymmetry in virtual photon-nucleon scattering, A1, on the 3He nucleus. Combined with the remaining E06-014 data, this will form the basis of a measurement of the neutron asymmetry An1 that will extend the kinematic range of the data available to test models of spin-dependent parton distributions in the nucleon.
Experiment Numbers: E99-117
Group: Hall A
Document: pdf
Accepted Manuscript:
Supporting Documents:
Supporting Datasets: