E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status...
-
Upload
martin-richard -
Category
Documents
-
view
220 -
download
0
description
Transcript of E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status...
![Page 1: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/1.jpg)
E97-110: Small Angle GDHExperimental Status Report
Vincent SulkoskyMassachusetts Institute of Technology
Hall A Collaboration MeetingDecember 15th, 2011
![Page 2: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/2.jpg)
MotivationPrecision measurement of the moments of spin
structure functions at low Q2, 0.02 to 0.24 GeV2 for the neutron (3He)
Covered an unmeasured region of kinematics to test theoretical calculations (Chiral Perturbation theory)
Complements data from experiment E94-010 covered region from 0.1 to 0.9 GeV2
Finalizing systematic uncertainties and first publication
![Page 3: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/3.jpg)
Neutron Spin Polarizabilities
![Page 4: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/4.jpg)
E97-110 Spin Polarizabilities
![Page 5: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/5.jpg)
Experiment E97-110 Inclusive experiment:
◦ Scattering angles of 6◦ and 9◦ ◦ Polarized electron beam:
Avg. Pbeam = 75%◦ Pol. 3He target (para & perp):
Avg. Ptarg = 40%
Measured polarized cross-section differences
Xee )',(He3
M. Amarian et al., PRL 89, 242301 (2002)
![Page 6: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/6.jpg)
Current WorkWaiting on final target polarization (J. Singh)Elastic 3He analysis (V. Laine)
◦2.1 GeV asymmetry and cross section completed◦Now working on 2.8 GeV data set
Finalize acceptance (V. Sulkosky)Radiative Corrections
◦Preliminary done by J. Singh; code now available◦Tim Holmstrom working on it
Estimation of QE contribution to neutron results (V. Sulkosky)
![Page 7: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/7.jpg)
9o Acceptance
Septum Mistuned15% uncertainty
Difficulty:◦ Saturation effect is present◦ A few settings were
mistuned with the septum magnet
◦ tg-acceptance appears squeezed at the highest field settings
◦ Varying acceptance cuts does not help
![Page 8: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/8.jpg)
Interpolation
• The interpolation method works, but there is a concern about the adjacent momentum settings.• Carbon cross section analysis to verify the absolute normalization of the data.
• || 3.6%• Removed edge bins with a secondary process• Corrected remaining edge imperfections with a secondary acceptance correction
![Page 9: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/9.jpg)
Tools for Carbon Cross Sections
Single carbon foil data were taken for each of the momentum settings for E = 3.775 GeV
Single Arm Monte-Carlo (SAMC) from A. Deur◦ Uses John LeRose transport functions at 9º and apertures ◦ Program complied with QFS subroutines to perform
radiative corrections: internal and external◦ Program utilizes the parameterized cross section for A> 2
from P. Bosted: https://userweb.jlab.org/~bosted/F1F209.f◦ Elastic radiative tail was removed using Rosetail averaged
over the solid angle acceptance of E97-110
![Page 10: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/10.jpg)
Septum Entrance Apertures
• Shift large angle side by 7mm• Shift small angle side by 5 mm
![Page 11: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/11.jpg)
Carbon Cross Section 2.007 GeV/c
![Page 12: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/12.jpg)
Carbon inelastic cross sections
![Page 13: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/13.jpg)
SummaryWork is progressingAcceptance analysis to be completed
soonMore work needs to go into radiative
corrections:1. Smoothing of the data completed (T.
Holmstrom)2. Finite acceptance for elastic tail subtraction3. Model for the two lowest energies
Draft of first paper completed and internally circulated
![Page 14: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/14.jpg)
Radiative Tail & Finite Acceptance
![Page 15: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/15.jpg)
Axial Anomaly and the LT Puzzle
N. Kochelev and Y. Oh; arXiv:1103.4891v1
![Page 16: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/16.jpg)
Systematic Uncertainties
![Page 17: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/17.jpg)
Analysis StatusPreliminary results for the moments have been
extracted at constant Q2.Collimator background is mostly from polarized 3He
◦ Need to estimate size of leakage into physics asymmetryIssues and analysis still in progress:
◦ Almost final target polarizations (J. Singh)Waiting to receive final numbers very soon.
◦ Elastic analysis as a cross check of systematics (V. Laine) 2.1 GeV completed; working on other energies now
◦ Acceptance: very messy but making steady progress◦ Finalize radiative corrections (J. Singh, T. Holmstrom & V.
S.)
![Page 18: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/18.jpg)
Updated SAMC CodeWork done by V. Laine`SAMC rewritten in C++ from FortranImproved implementation of target
collimator cutsRaster correction by calculating electron’s
travel length through the cellRadiative corrections made for each material
separately (previously done all at once)Default units now in meter, gram, GeV and
radian instead of cm and mrad
![Page 19: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/19.jpg)
Cross Section Smoothing3.319 GeV, 9o
4.404 GeV, 9o
Work by T. Holmstrom
![Page 20: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/20.jpg)
Delta Acceptance
E94-010
E97-110
• Flat region of -acceptance is much smaller with Septum• Simulation is not perfect on the falling edges
![Page 21: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/21.jpg)
6o Acceptance Solutions
• || 3.6%• Removed edge bins with a secondary process• Corrected remaining edge imperfections with a secondary acceptance correction
![Page 22: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/22.jpg)
9-Degree AcceptanceMore painful:
◦Saturation effect is present
◦A few settings were mistuned with the septum magnet
◦tg-acceptance appears squeezed at the highest field settings
![Page 23: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/23.jpg)
Variation of Acceptance Cuts
Varying acceptance cuts does not help
![Page 24: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/24.jpg)
Elastic Asymmetry Analysis
Work by V. Laine`
![Page 25: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/25.jpg)
3He Elastic AcceptanceDelta
ytg W-M
tg tg
![Page 26: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/26.jpg)
Elastic Cross Section Analysis
Work by V. Laine`
10 A; VDC 19% multi-tracks
Average
![Page 27: E97-110: Small Angle GDH Experimental Status Report E97-110: Small Angle GDH Experimental Status Report Vincent Sulkosky Massachusetts Institute of Technology.](https://reader036.fdocuments.us/reader036/viewer/2022062317/5a4d1b157f8b9ab0599912fd/html5/thumbnails/27.jpg)
Kinematic Coverage