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Some Attempts to The Separation of Coherent and Incoherent ψ Production. Po-Ju Lin August 3,2004. Contents. Coherent – Incoherent - definition - t-dependence ν- correlation The mysterious band t and t_LD2/t_LH2 distribution Summary.
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Some Attempts to The Separation of Coherent and Incoherent ψ Production Po-Ju Lin August 3,2004
Contents • 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.
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
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
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
Missing Mass of The Mysterious Band Figure 1 - LD2 Figure 2 - 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 scaleFigure 4 – Zoom in
Summary • No really useful present method can efficiently separate coherent and incoherent events.