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E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Hall A Collaboration Meeting Xiaohui Zhan MIT prsented by Measurement.

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Presentation on theme: "E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Hall A Collaboration Meeting Xiaohui Zhan MIT prsented by Measurement."— Presentation transcript:

1 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Hall A Collaboration Meeting Xiaohui Zhan MIT prsented by Measurement of A x and A z Asymmetries in the quasi-elastic 3 He(e,e'd) reaction

2 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Main Physics Goals General: Achieve a better understanding of the ground-state spin structure of 3 He, i.e. improve our understanding of 3 He rather than using it as an effective neutron target. Specific: Test state-of-the-art Faddeev calculations and use these calculations to gain a better understanding of the dynamics and the S' and D wave-function components of 3 He. This is accomplished by making precision measurements of the double polarized 3 He(e,e'd) reaction. Impact: All experiments using 3 He as a polarized neutron target.

3 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction An A 1 Example: Shown are the error bars from a recent Hall A polarized 3 He experiment: PRL 92 (2004) At 12GeV this measurement becomes limited by our understanding of 3 He.

4 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Ground State of 3 He S spatially symmetric, 90% of spin-averaged WF, neutron target Dgenerated by tensor component of NN force, 8.5% S'mixed-symmetry configuration, 1.5% As a function of missing momentum, these relative contributions can affect the (e,e'N) reaction differently. e.g. the NIKHEF D(e,e'p) results: PRL 89 (2002)

5 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Why detect the quasi-elastic Deuteron? Unique isoscalar-isovector interference in 3 He(e,e'd)

6 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Sketch of Experiment single arm elastic electron quasi-elastic electron quasi-elastic deuteron target spin parallel and perpendicular to q

7 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction BigBite Spectrometer During SRC Experiment

8 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Ingredients of the Theory Calculations Faddeev Calculation Final State Interactions AV18 NN Potential Urbana IX 3NF - large CPU effort for small effect Coulomb Interactions Standard MEC Charge-Density MEC (sensitive to high momentum components) Faddeev Calculation Final State Interactions Refit CD Bonn NN Potential (previously used Paris NN Potential) Delta degrees of freedom used to provide 3NF Coulomb Interactions Standard MEC Relativistic 1-Body Charge Corrections Bochum/Krakov Group Hannover Group Blue Items are New Since PAC 22

9 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Bochum/Krakow Group Ingredients Q 2 fixed by HRS and the missing momentum range bitten without moving BigBite

10 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Hannover Group Ingredients Q 2 fixed by HRS and the missing momentum range bitten without moving BigBite

11 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Head-to-Head Comparison Groups are presently working together to understand the source(s) of disagreement. Different NN potentials along with charge-density MEC are presently being investigated. Hannover Curves Updated From Those Shown In The Proposal

12 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Bochum/Krakow WF Truncations Both Bochum/Krakow and Hannover Groups are doing WF truncation calculations.

13 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Sensitivity to S' The same technique as used to extract Form Factors from asymmetry data.

14 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Analysis of Proton Events These New CPU Intensive Calculations Have Just Become Available both (e,e'p) and (e,e'd) will be detected in BigBite proton asymmetry is not sensitive to S' part of the wave-function

15 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Addition of a HAND Hall A Neutron Detector Fully Assembled And Tested DAQ and Cables Available A Commitment of Manpower

16 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Measurement of GEn by HAND Systematics Limited Measurement Expected Result is Shown with the Conservative Estimate

17 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Summary & Status Standard HRS BigBite and Neutron Detector PMTs need to be tested Wirechambers same as will be used for d2 and Transversity 3He system similar to d2 and Transversity We will take the Benchmark Data at a fixed Q2 in (e,e'd) and (e,e'p) simultaneously over a broad range of missing momentum that the Bochum/Krakow and Hannover groups insist is needed to verify their calculations. This data will allow significant progress to be made on understanding of the three-body system. We were approved for 15 PAC days of polarized electrons beams.

18 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Extra Slides

19 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction NIKHEF Double Asymmetry Deuteron Data

20 E05-102: Measurement of A x and A z asymmetries in the quasi-elastic 3 He(e,e'd) reaction Hannover Group WF Truncations


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