Measurement of double polarized asymmetries in quasi-elastic processes 3He⃗(e⃗,e′d){}^3\vec{He}(\vec{e},e' d) and 3He⃗(e⃗,e′p){}^3\vec{He}(\vec{e},e' p)

This thesis is dedicated to a study of a spin-isospin structure of the polarized ${}^3\mathrm{He}$. First, an introduction to the spin structure of ${}^3\mathrm{He}$ is given, followed by a brief overview of past experiments. The main focus of the thesis is the E05-102 experiment at Jefferson Lab, in which the reactions ${}^3\vec{\mathrm{He}}(\vec{\mathrm{e}},\mathrm{e'} \mathrm{d})$ and ${}^3\vec{\mathrm{He}}(\vec{\mathrm{e}},\mathrm{e'} \mathrm{p})$ in the quasi-elastic region were studied. The purpose of this experiment was to better understand the effects of the S'- and D-state contributions to the ${}^3\mathrm{He}$ ground-state wave-functions by a precise measurement of beam-target asymmetries $A_x$ and $A_z$ in the range of recoil momenta from 0 to about $300 \mathrm{MeV}/c$. The experimental equipment utilized in these measurements is described, with special attention devoted to the calibration of the hadron spectrometer, BigBite. Results on the measured asymmetries are presented, together with first attempts at their comparison to the state-of-the art Faddeev calculations. The remaining open problems and challenges for future work are also discussed.Comment: Doctoral thesis, 234 page

Precision measurements of A1N in the deep inelastic regime

We have performed precision measurements of the double-spin virtual-photon asymmetry A1A1 on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized 3He target. Our data cover a wide kinematic range 0.277≤x≤0.5480.277≤x≤0.548 at an average Q2Q2 value of 3.078 (GeV/c)2, doubling the available high-precision neutron data in this x range. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in the same kinematic range. Our data are consistent with a previous observation of anA1n zero crossing near x=0.5x=0.5. We find no evidence of a transition to a positive slope in(Δd+Δd¯)/(d+d¯) up to x=0.548x=0.548