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

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

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.

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

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

Distribution Diagrams of LD2 and LH2 Data

Incoherent vs. Coherent Plot of LD2 and LH2

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

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

ν vs. Distribution Plots for LD2

ν vs. Distribution Plots for LH2

Step Zoom In step size: = 0.2 = 0.1

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

Colliding-Mass of The Mysterious Band

Missing Mass of The Mysterious Band Figure 1 - LD2 Figure 2 - LH2

4. Momentum Transfer t for LD2 and LH2

t_LD2/t_LH2 Ratio Plot

Photon-energy vs. t for LD2 and LH2

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

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

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