some attempts to the separation of coherent and incoherent ψ production
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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. - PowerPoint PPT PresentationTRANSCRIPT
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
2q
1. Coherent - Incoherent
Definition
1. Coherent ψ production : The incoming photons interact with nucleus as a whole.
2. 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:
1. High-| t | region: Incoherent process dominates
2. Low-| t | region: Coherent process dominates
2 PPt
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
PP
NN
mqm
mqm
22
22
q
Nm Pm
ν vs. Distribution Plots for LD2 2q
ν vs. Distribution Plots for LH2 2q
Step Zoom In
step size:
= 0.2
= 0.1
2q
3. The Mysterious band
The band above the incoherent interaction line in both LD2 and LH2 diagrams.
Property analysis
1. Colliding mass : direct fit from diagram using correlation formula.
2. 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.