The missing mass
- Topology = 01 : γ p -> p π+ ( π- )
- Topology = 02 : γ p -> p π- ( π+ )
- Target = 01 : Butanol Target
- Target = 03 : CH2 Target
The cut used by the FSU group was updated. This cut is divided to the two part. The first part is the Basic Cut (The vertex Cut, The beta Cut, and The accidental Cut) and the second is called the signal Cut. The signal Cut has two : KinF Cut and MM Cut. I will describe what are the KinF Cut and the MM Cut. I will show the plots of the missing masses after applying these cuts.
The kinematic fitting gives particle's four vectors as the output. I make the plot using these four vectors like making the missing-mass plot. And then I applied the cut (KinF Cut).
MyMissingVectorKinF= MyInitial - MyPro_sit2_KinF - MyPim_sit2_KinF;
I select the missing mass part using the MM_Cut.
| proton | [0.8,0.96] |
| pion | [0.006,0.04] |
| 0.006 < KinF_Cut < 0.04 |
0.006 < MM_Cut < 0.04 |
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1. The pion's missing-mass in the double-pion photoproduction
Topology γ p -> p π+ ( π- )
| π- mass : 137.7 MeV |
π- mass : 138.9 MeV |
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Topology γ p -> p π- ( π+ )
| π+ mass : 138.3 MeV |
π+ mass : 138.8 MeV |
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2. The missing mass in the three kinds of targets
I have made the missing mass in each topology and each target. They are made after applying Energy Loss, FSU Energy Correction, and FSU Momentum Correction. However, the red plots with w/o Eloss are made without corrections.
Topology γ p -> p π+ ( π- )
Topology γ p -> p π- ( π+ )
Topology γ p -> π+ π- ( p )
Topology γ p -> p π+ π- ( )
3. The missing mass in the different momentum particle
The missing mass plots are made in the several proton or π+ momentums (red line).
| γ p -> p π+ (π-) |
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| γ p -> p π- (π+) |
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There is divot geometry in the part of momentum pi-
| γ p -> π+ π- ( p ) |
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There is some problems in the missing mass plot of the pi+ between 500 and 900 MeV.
A
| γ p -> p π+ π- ( ) |
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Sungkyun Park
Last modified: Nov 07, 2010
