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Joe Katich's Research Page


My Thesis Experiment: Ay
(Jefferson Lab, Experiment E05-015)
Measurement of the Target Single-Spin Asymmetry in Quasi-Elastic 3He(e,e')

Abstract:
We propose to measure the target single-spin asymmetry, Ay, for the neutron using the inclusive quasi-elastic 3He(e, e') reaction in Hall A with a vertically polarized 3He target at Q2 = 1.0 and 2.3 GeV2. In the one-photon exchange approximation, Ay is identically zero due to time-reversal invariance. However, it is also sensitive to the two-photon exchange amplitude which can be non-zero and enters Ay through the interference between the one- and two-photon amplitudes. For large enough Q2, where the scattering predominantly occurs from asymptotically-free partons, there are contributions from both the elastic and inelastic nucleon response during two-photon exchange. Calculation of the elastic response is straight-forward and yields an asymmetry of Any,elas≈ 0.005 for the neutron at the kinematics of this experiment. The inelastic response was recently calculated using models of Generalized Parton Distributions (GPD's) as input and is on the order of Any,inel≈-0.01, which gives a total expected asymmetry of Any≈0.015. Two different moments, each containing two of the GPD's, are needed to fully describe the inelastic response. However for the neutron, Ay is dominated by just one of these moments that contains the GPD's, Hq and Eq, that are also related to the nucleon form factors and the total angular momentum contribution to the nucleon spin from the quarks. This experiment will be performed using the standard Hall A spectrometers and a vertically polarized3He target and will measure Any with an absolute statistical uncertainty of delta(Ay)≈ 0.0023 at each Q2 (15% relative to the prediction above.) This experiment will be the first to firmly establish a non-vanishing Ay, a T-odd quantity that is identically zero in the Born approximation, providing new constraints on GPD models and new information on the dynamics of the two-photon exchange process.

Download the Entire Proposal: (PDF)
Download My Ay Poster: (.ppt)
View The Poster on the Web: Click Here
Rb Atomic Structure: Click Here
Other Relevant Physics Websites
3He NMR Lab at W&M
Jefferson Lab Experimental Hall A
Hadronic Physics Group at W&M
HAPPEX Homepage
GEn Homepage
Sarah Phillips' Reference List




Publications:
HAPPEX 2006



A Few TeX Notes I've Bothered to Write Up:
Some Rate and Error Calculations for Ay (pdf)
A quick and dirty summary of 3He(pdf)


Download the Cell Characterization Files


Relevant Papers:
Resonance estimates for single spin asymmetries in elastic electron-nucl eon scattering (B. Pasquini, M. Vanderhaeghen) (pdf)
Delta resonance contribution to two-photon exchange in eletron-proton scattering (S. Kondratyuk, P. G. Blunden): (pdf)
Two photon exchange in elastic electron-nucleon scattering (P. G. Blunden, W. Melnitchouk, J. A. tjon) (pdf)
Single Spin Asymmetries in elastic electron-nucleon scattering (B. Pasquini, M. Vanderhaeghen) (pdf)


A few others:

Mike Romalis' Thesis - tons of stuff on polarized 3He targets (ps)
A thesis on measuring A1n...very similar physics:(pdf)
GEn Experiment (E02-013) Proposal (pdf)


Why I Should Receive a JSA Fellowship


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