Difference between revisions of "03/31/2020"

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Present: M.D., A.D., S.S, J.S.
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Present: M.D., A.D., S.Š, J.S.
  
 
*General:
 
*General:
  
*MD:Produced new simulation plots with the correct beam spectrum and random background for the hadronic part:
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*MD:Produced new simulation plots with the correct beam spectrum and random background for the hadronic part.
**[https://halldweb.jlab.org/wiki/index.php/File:Beam_bggen_30980.png hadronic events], [https://halldweb.jlab.org/wiki/index.php/File:Beam_gen_compton_simple_30980.png Compton Events], [https://halldweb.jlab.org/wiki/index.php/File:PPerpSum_bggen_30980.png Transverse momentum distribution for hadronic events], [https://halldweb.jlab.org/wiki/index.php/File:PPerpSum_gen_compton_simple_30980_2.png Transverse momentum distribution for Compton events], [https://halldweb.jlab.org/wiki/index.php/File:Pprot_bggen_30980.png Proton momentum distribution]
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**Plots:
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***[https://halldweb.jlab.org/wiki/index.php/File:Beam_bggen_30980.png hadronic events]
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***[https://halldweb.jlab.org/wiki/index.php/File:Beam_gen_compton_simple_30980.png Compton Events]
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***[https://halldweb.jlab.org/wiki/index.php/File:PPerpSum_bggen_30980.png Transverse momentum distribution for hadronic events]
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***[https://halldweb.jlab.org/wiki/index.php/File:PPerpSum_gen_compton_simple_30980_2.png Transverse momentum distribution for Compton events]
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***[https://halldweb.jlab.org/wiki/index.php/File:Pprot_bggen_30980.png Proton momentum distribution]
 
**It will take more work to get the correct beam spectrum and background for all the generators.
 
**It will take more work to get the correct beam spectrum and background for all the generators.
 
**The efficiency is now also determined for the sum of the transverse momentum of the final state.
 
**The efficiency is now also determined for the sum of the transverse momentum of the final state.
 
**There is a Compton (ge->ge) generator which shows that only about 10% efficiency for triggering even without optimization.
 
**There is a Compton (ge->ge) generator which shows that only about 10% efficiency for triggering even without optimization.
 
**There are a couple of Bethe Heitler generators that I'm looking into but they need to be modified to do what we want.
 
**There are a couple of Bethe Heitler generators that I'm looking into but they need to be modified to do what we want.
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*SŠ: Coded the unpolarized and polarized Bethe-Heitler formulae, see [https://halldweb.jlab.org/wiki/images/3/36/Bh.pdf his report]
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**AD's comments on Simon's document:
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***BH asymmetries seem very small. For GDH, we are looking at asymmetries at the 3% level (see e.g. Helbing review's Fig. 38: Δσ 10 μb, with A=Δσ/(2σ₀). It seems the BH asymmetry is lower by significantly more an order of magnitude. Further, Mark simulation indicate a 10% trigger efficiency for BH, so if it is true, Δσ is further suppressed by an order of magnitude.
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This points toward the possibility that we can ignore the BH for the proposal.
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***Regarding the structure functions for the asymmetry, the atomic form factors should not be needed since the atoms are not polarized.
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***For g<sub>1</sub>  and g<sub>2</sub>, probably only their values at very small-x that are truly relevant. If so, one can use a simple Regge parameterization of g<sub>1</sub>, see e.g. arXiv:1808.03202. For g<sub>2</sub>, we could just assume g<sub>2</sub><sup>ww</sup>(x,Q²)=-g<sub>1</sub>(x,Q²)+ ∫<sub>x</sub>¹g₁(y,Q²)/y dy.
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***For question #2, the angle coverage, we are planing to use the Compton Calorimeter, which cover down to 0.2°. (Note: we do not have the ComCal in the simulation yet).

Revision as of 06:51, 31 March 2020

Present: M.D., A.D., S.Š, J.S.

  • General:
  • SŠ: Coded the unpolarized and polarized Bethe-Heitler formulae, see his report
    • AD's comments on Simon's document:
      • BH asymmetries seem very small. For GDH, we are looking at asymmetries at the 3% level (see e.g. Helbing review's Fig. 38: Δσ 10 μb, with A=Δσ/(2σ₀). It seems the BH asymmetry is lower by significantly more an order of magnitude. Further, Mark simulation indicate a 10% trigger efficiency for BH, so if it is true, Δσ is further suppressed by an order of magnitude.

This points toward the possibility that we can ignore the BH for the proposal.

      • Regarding the structure functions for the asymmetry, the atomic form factors should not be needed since the atoms are not polarized.
      • For g1 and g2, probably only their values at very small-x that are truly relevant. If so, one can use a simple Regge parameterization of g1, see e.g. arXiv:1808.03202. For g2, we could just assume g2ww(x,Q²)=-g1(x,Q²)+ ∫x¹g₁(y,Q²)/y dy.
***For question #2, the angle coverage, we are planing to use the Compton Calorimeter, which cover down to 0.2°. (Note: we do not have the ComCal in the simulation yet).