1. Some Attempts to The Separation of Coherent and Incoherent ψ Production
Po-Ju Lin
August 3,2004

2. Contents ν- correlation The mysterious band
Coherent – Incoherent
- definition
- t-dependence
ν- correlation
The mysterious band
t and t_LD2/t_LH2 distribution
Summary

3. 1. Coherent - Incoherent Definition
Coherent ψ production : The incoming photons interact with nucleus as a whole.
Incoherent ψ production : Photons penetrate into nucleus and interact with nucleon i.e. proton.

4. Characteristic t-dependence
1. Coherent - Incoherent
Characteristic t-dependence
Due to the resolving ability of particles exchanged:
High-| t | region: Incoherent process dominates
Low-| t | region: Coherent process dominates

5. 1. Coherent - Incoherent
Our goal is to separate coherent and incoherent event from LD2 data
We use LH2 data as pure incoherent sample to make comparison

6. Distribution Diagrams of LD2 and LH2 Data

7. Incoherent vs. Coherent Plot of LD2 and LH2

8. Comparison of LD2 and LH2 Distribution for coherent and incoherent events.

9. 2. Correlation between Energy Transfer and Three Momentum Transfer
From the conservation of four momentum, we acquire this correlation:
Where = energy transfer
= three momentum transfer
= nucleus mass = proton mass

10. ν vs. Distribution Plots for LD2

11. ν vs. Distribution Plots for LH2

12. Step Zoom In
step size:
= 0.2
= 0.1

13. 3. The Mysterious band
The band above the incoherent interaction line in both LD2 and LH2 diagrams.
Property analysis
Colliding mass : direct fit from diagram using correlation formula.
Missing mass

14. Colliding-Mass of The Mysterious Band

15. Missing Mass of The Mysterious Band
Figure 1 - LD Figure 2 - LH2

16. 4. Momentum Transfer t for LD2 and LH2

17. t_LD2/t_LH2 Ratio Plot

18. Photon-energy vs. t for LD2 and LH2

19. t_LD2/t/LH2 plots for Different Photon Energy Bin
Bin size : 0.2
E-gamma :1.5 ~ 2.5

20. Overlapped t_LD2/t_LH2 of Different Photon Energy Bin
Figure 3 – original scale Figure 4 – Zoom in

21. Summary
No really useful present method can efficiently separate coherent and incoherent events.