Quality Checks
Quality Checks
Run Summary Table
The table below uses a characteristic DST file to try and estimate the sample size for a semi-inclusive analysis of pion electroproduction. The column marked "cuts" below indicates the number of events kept when the standard EC based electron identification cuts, described above, are used:
. The next step will be to compare unpolarized pion production rates in order to evaluate the CLAS detectors efficiencies for measuring charged pions with different torus polarities. The question is whether you get the same rates for negatively charged pions in one torus polarity to positively charged pions using the opposite torus polarity.
Beam Energy | Torus Current | Target | Begin Run | End Run | file used | # trig( | )events remaining after | cuts(%)expected # evts( | )events remaining after | and cuts(%)expected # evts( | )events remaining after | and cuts(%)expected # evts( | )
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4239 | 2250 | NH3 | 28205 | 28277 | /cache/mss/home/nguler/dst/dst28205_05.B00 | 1108.72 | 60.8 | 674.1 | 8.3 | 92.02 | 3.24 | 35.92 |
ND3 | 28074 | 28190 | /cache/mss/home/nguler/dst/dst28187_05.B00 | 1117.87 | 59.6 | 666.25 | 7.99 | 89.32 | 3.3 | 36.9 | ||
-2250 | NH3 | 28407 | 28479 | /cache/mss/home/nguler/dst/dst28409_05.B00 | 1013.57 | 24.2 | 245.28 | 0.12 | 1.22 | 0 | 0 | |
ND3 | 28278 | 28403 | /cache/mss/home/nguler/dst/dst28400_05.B00 | 1556.04 | 23.9 | 371.89 | 0.02 | 0.31 | 0.05 | 0.51 | ||
5735 | 2250 | NH3 | 27074 | 27195 | /cache/mss/home/nguler/dst/dst27095_05.B00 | 1442.25 | 57.7 | 832.18 | 9.3 | 134.13 | 3.8 | 59.13 |
ND3 | 27116 | 27170 | /cache/mss/home/nguler/dst/dst27141_05.B00 | 624.55 | 59.1 | 369.10 | 9.53 | 59.52 | 3.9 | 24.36 | ||
-2250 | NH3 | 26911 | 27015 | /cache/mss/home/nguler/dst/dst26988_05.B00 | 900.93 | 80.7 | 727.05 | 7.14 | 64.33 | 9.9 | 89.19 | |
ND3 | 27022 | 27068 | /cache/mss/home/nguler/dst/dst27055_05.B00 | 711.53 | 80 | 569.22 | 6.97 | 49.59 | 10.1 | 71.86 |
Rates
Unpolarized Pion electroproduction
Rates from other experiments in our Kinematic range
Center of Mass Frame Transformation
We have proton and electron. In the Lab frame electron is moving along the x-axis with momentum ;
- Lab Frame
- CM Frame
- :
- Find
Using the last two equations we will get the following for x component:
Example of the Missing Mass Calculation for the following reaction
- : electron mass is neglibible
- : Mass of a proton
- Electron
- Proton
- Missing Mass
- Conservation of the 4-momentum gives us following
- Solving it for the final proton state
- In our case 4-vectors for particles are
- Plug and chug
] [ + - -
Example of the Missing Mass Calculation for the following reaction
Used file dst27095_05.B00. Target
- : electron mass is negligible
- : Mass of a proton
- : Mass of a neutron
- Electron
- Neutron
- Missing Mass Calculation
- Below is the conservation of the 4-momentum
- Solving it for the final neutron state
- The 4-vectors for the particles in this event
] [ + - -
transformation from LAB frame to CM frame
Used file dst27095_05, event_number=3106861
- Calculation of
- Calculation of
- Calculation of
Missing_Mass(experimental data)
The mean value of the missing mass is around 2.056 GeV.
angle
angle for electrons and pions ( ) in lab frame ,
![]() Electron fiducial cut at electron momentum range : 2.15 < < 2.53 GeV for sector 1. The histograms on the right show the < distributions at two values of . The highlighted area in the center indicates the selected fiducial range. [1] |
NEW STUFF
Below is shown histograms before changing angles by sectors for pions and electrons.
ANGLE DISTRIBUTION FOR ELECTRONS AND PIONS, FILE dst27095_05 | |
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ELECTRONS | PIONS(prt_id=4) |
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SECTOR_VS_ | FOR ELECTRONS AND PIONS, FILE dst27095_05|
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ELECTRONS | PIONS(prt_id=4) |
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e_theta_vs_phi_angle_difference with cuts (e_p<3, | , ), no cuts on sc_paddle and nphe||
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SECTOR 1 | SECTOR 2 | SECTOR 3 |
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SECTOR 4 | SECTOR 5 | SECTOR 6 |
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For Electrons theta_vs_phi with cuts (e_p<3, | , ), no cuts on sc_paddle and nphe||
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SECTOR 1 | SECTOR 2 | SECTOR 3 |
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SECTOR 4 | SECTOR 5 | SECTOR 6 |
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Graph
for Pions hitting paddle #7. The y-axis should be pion counting rate in units of pions per nanCoulomb.
angle in the Center of Mass Frame
The variables below are in Lab Frame:
From the above picture we can write down the momentum x,y and z components for pion in terms of angle and total momentum.
where
- Target Nucleon 4-momentum
- Scattered electron 4-momentum
- Hadron final state 4-momentum
- Meson final state 4-momentum
In Inclusive
Then The Missing Mass
In Exclusive
Then Missing Mass
Conservation of 4-momentum gives
- 4-momentum of the exchanged virtual photon( )
First the coordinate system is rotated around z-axis by
Phi rate
Why does theangle only go out to 80 degrees?
Add FC histogram(done)
Add plot from paper(done),
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start calculating cross -section, Find luminosity of NH3 target used
The luminosity of the continuous electron beam was [4] [5]
Insert Luminosity calculation for NH3 and ND3 targets
where
- is the Luminosity.
- is the number of interactions.
- is the total cross section.
- is the differential solid angle.
- is the differential cross section.
Conservation of Momentum
:
Conservation of Energy
:
The
Pion Rates -vs- Paddle for opposite sign Torus fields
- using all events in which the first particle (the one which caused the trigger) is defined as an electrons and passes the
sc_paddle vs X_bjorken 5.7 GeV Beam Energy
no cuts | cuts | no cuts | cuts |
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Electrons | B > 0 | B<0 | |
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B > 0 | B<0 | ||
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B > 0 | B<0 | ||
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sc_paddle vs X_bjorken with cuts 5.7 GeV Beam Energy(number of events=2)
B>0 | B<0 |
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B>0 | B<0 |
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sc_paddle vs Momentum 5.7 GeV Beam Energy
There is a curvature problem. When B > 0 then I expect the high momentum electrons to hit the lower paddle numbers (inbending). I can see this when I look at the B>0 plot for electrons with cuts. When B < 0 then the electrons are bending outwards which makes me expect the the higher momentum electrons will high the higher numbered paddles. I do not see this for B>0 with electron cuts.
no cuts | cuts | no cuts | cuts |
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Electons | B > 0 | B<0 | |
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B > 0 | B<0 | ||
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B > 0 | B<0 | ||
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sc_paddle vs Momentum with cuts 5.7 GeV Beam Energy(number of events=2)
B>0 | B<0 |
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B>0 | B<0 |
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Used file dst26988_05.B00(Energy=5.7GeV and Torus=-2250)
Paddle 7 Rates and statistics
The number of events per trigger is measured for the respective DST file above and then the Total number events in the data set is estimated from that.
(B>0) | (B<0) | |||
---|---|---|---|---|
Total Number Events | Number events per | triggersTotal Number Events | Number events per | trigger|
0.1 | 5.1 | 71 | 24.6 | 547 |
0.2 | 6.9 | 96 | 13.7 | 305 |
0.3 | 3.7 | 51 | 6.2 | 137 |
0.4 | 3.3 | 45 | 2.7 | 60 |
0.5 | 0.9 | 13 | 0.99 | 22 |
Paddle 17 Rates and statistics
(B<0) | (B>0) | |||
---|---|---|---|---|
Total Number Events | Number events per | triggerTotal Number Events | Number events per | trigger|
0.1 | 6.2 | 137 | 4.6 | 64 |
0.2 | 3.5 | 79 | 4.9 | 67 |
0.3 | 1.7 | 39 | 2.6 | 36 |
0.4 | 0.3 | 7 | 2.1 | 29 |
0.5 | 0.1 | 2 | 0.6 | 8 |
Paddle 5 and 8 Rates and statistics for electrons
sc_paddle=5 (B>0) | sc_paddle=8 (B<0) | |||
---|---|---|---|---|
Total Number Events | Number events per | triggerTotal Number Events | Number events per | trigger|
0.1 | 384.9 | 5.314 | 1665.2 | 3.706 |
0.2 | 382.5 | 5.282 | 977.8 | 2.176 |
0.3 | 264.9 | 3.657 | 567.1 | 1.262 |
0.4 | 159.5 | 2.202 | 328.6 | 0.7313 |
0.5 | 99 | 1.367 | 218.2 | 0.4856 |
Histograms for 5.7 GeV Beam Energy
Electron energy/momentum | Electron Theta ( | )Electron Qsqrd | Electron X_bjorken |
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B>0 and sc_paddle=5 | |||
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B<0 and sc_paddle=8 | |||
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Normalized X_bjorken for electrons
B>0 and sc_paddle=5 | B<0 and sc_paddle=8 |
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Asymmetries
Systematic Errors
Media:SebastianSysErrIncl.pdf Sebastian's Writeup