Difference between revisions of "03/31/2020"
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| − | Present: M.D., A.D., S. | + | 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: | + | *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] | + | **Plots: |
| + | ***[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] | ||
**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. | ||
| + | |||
| + | *SŠ: Coded the unpolarized and polarized Bethe-Heitler formulae, see [https://halldweb.jlab.org/wiki/images/3/36/Bh.pdf 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 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. | ||
| + | ***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 07:51, 31 March 2020
Present: M.D., A.D., S.Š, J.S.
- General:
- MD:Produced new simulation plots with the correct beam spectrum and random background for the hadronic part.
- Plots:
- 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.
- 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.
- 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.
- AD's comments on Simon's document:
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).
