Analysis

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EG1 run database
run summary
polarization info

Particle Identification

Electron

Cuts

Calorimeter based cuts

The distributions below represent two types of cuts applied to improve the electron particle identification (PID) using a 4 GeV electron beam incident on an NH3 target. The electron calorimeter is segmented into an inner[math]EC_{inner}[/math] and an outer[math]EC_{outer}[/math] region. The total energy absorbed by the calorimeter system is recorded in the variable [math]EC_{tot}[/math]. The momentum ([math]P[/math]) is calculated using the reconstructed track and the known torus magnetic field. The distributions of [math]EC_{tot}[/math] and [math]EC_{inner}[/math] are shown below where both have been divided by the electron momentum and no cuts have been applied.


[math]EC_{tot}\gt 0.2*p[/math]

Without any cuts we have 181018 entries. After using the following cut [math]EC_{tot}\gt 0.2*p[/math] we are getting 127719 entries, which is about 70.55% of 181018.

Etotal P using tot cut.gif Einner P using tot cut.gif

[math]EC_{inner}\gt 0.08*p[/math]

After the cut on the energy deposited into inner part of electron calorimeter, number of entries decreases by 22%.

Etotal P using inner cut.gif Einner P using inner cut.gif

Both cuts [math] EC_{tot}\gt 0.2*p [/math] and [math] EC_{inner}\gt 0.08*p [/math]

In case of using the cuts of the total deposited energy and the energy deposited into inner calorimeter number of entries decreases ~36%

Etotal P using both cuts.gif Einner P using both cuts.gif

summary table

The "# of triggers" columns represents the number of events which generated a signal above threshold in the calorimeter and the scintillator. The expected # of events column represents the number of reconstructed events with tracks that also make it through the cuts defined in the table.

The semi-inclusive analysis will focus on the 4 GeV and 6 GeV data which have both inbending and outbending torus settings. Specifically runs 28074 - 28579 ( 4 GeV) and Runs 27356 - 27499 and 26874 - 27198 (6 GeV)


Beam Energy Torus Current Begin Run End Run file used cuts # trig([math]10^6[/math]) expected # evts([math]10^6[/math]) p<3,[math]EC_{tot}\gt 0.2*p [/math],[math] EC_{inner}\gt 0.08*p[/math](%) p>3,[math]EC_{tot}\gt 0.24*p [/math],[math] EC_{inner}\gt 0.06*p[/math](%)
[math]EC_{tot}\gt 0.2*p[/math] [math]EC_{inner}\gt 0.08*p[/math] [math]EC_{tot}\gt 0.2*p [/math] and [math] EC_{inner}\gt 0.08*p[/math]
1606 1500 25488 25559 dst25504_02.B00 64% 49.5% 78% 60 3.2
1606 1946 25560 25605 44
1606 1500 25669 25732 dst25669_02.B00 64% 49% 78% 226 10
1606 1500 25742 26221 dst25754_02.B00 21% 11% 24% 3154 13.3
1606 -1500 26222 26359 dst26224_02.B00 4.6% 3% 6.6% 703 13.1
1724 -1500 27644 27798 dst27649_02.B00 4.8% 2.2% 5.9% 211 20
1724 1500 28512 28526 159
1724 -1500 28527 28532 93
2288 1500 27205 27351 dst27225_02.B00 20.2% 13% 25.6% 1647 16.1
2562 -1500 27799 27924 dst27809_02.B00 5.7% 4.6% 8.6% 1441 13.1
2562 -1500 27942 27995 dst27942_02.B00 6.1% 4.4% 8.9% 841 32.3
2562 1500 28001 28069 dst28002_02.B00 27.8% 13% 29.6% 1013 30.7
2792 -1500 27936 27941 dst27937_02.B00 6.7% 5% 9.9% 69 20.6
3210 -2250 28549 28570 436
4239 2250 28074 28277 dst28075_02.B00 35.3% 23.9% 40.5% 2278 19.6
4239 -2250 28280 28479 dst28281_02.B00 9.1% 9.4% 13.6% 2620 15.2
4239 2250 28482 28494 7
4239 -2250 28500 28505 107
4239 2250 28506 28510 dst28509_02.B00 29.5% 22% 36% 75 18.1
5627 2250 27356 27364 dst27358_02.B00 33.2% 27.8% 41.3% 56 19.4 44.6 40.1
5627 -2250 27366 27380 dst27368_02.B00 12.6% 14.8% 19.5% 130 13.6 25.3 8.8
5627 2250 27386 27499 dst27388_02.B00 33.4% 27.8% 41.4% 1210 20.2 44.8 40.1
5627 965 27502 27617 493
5735 -2250 26874 27068 dst26904_02.B00 13% 15% 20% 1709 19.9 25.6 9.1
5735 2250 27069 27198 dst27070_02.B00 33.3% 28.8% 42.2% 1509 15 46 40.2
5764 -2250 26468 26722 dst26489_02.B00 12.2% 14.4% 19.1% 1189 10 24.6 9.3
5764 0 26723 26775 268
5764 -2250 26776 26851 dst26779_02.B00 13.5% 15.5% 20.5% 662 15.9 26.4 9.2

Cut on the number of photoelectrons

In this case is used a cut on the number of photoelectrons, which is [math]nphe\gt 2.5[/math]. The plots below show the effect of the number of photoelectrons cuts on the Cerenkov distribution. We see that after using cut the number of entries decreases ~40.7%

Nphe before cut file 27070.gif Nphe1 after cut file 27070.gif


Used cuts [math]EC_{tot}\gt 0.24p[/math] and [math]EC_{inner}\gt 0.06p[/math]


Nphe before electron cuts file 27070.gif Nphe1 after electron cuts file 27070.gif


Used file dst28181_03(energy 4.2GeV). In this case was applied cuts on the polar angle([math]15\lt \theta\lt 20[/math]) and momentum([math]2.2\lt P\lt 2.6[/math]). Number of entries decreased by 96%(?????????????/)


Nphe before cuts file 28181.gif Nphe1 after cuts file 28181.gif

Tamuna: follow this link to see the OSIPENKO cuts described in part 5 add graphs of their effect below
Dr. Forest I think I did this cuts but they do not change a lot. Maybe I am wrong.

Plot of [math]EC_{tot}/p[/math] vs [math]EC_{inner}/p[/math]

In this case is used file dst27070(Energy 5.735 GeV and Torus 2250) and are applied the following EC cuts: For ECtotal - [math]EC_{tot}\gt 0.2p[/math], for EC inner - [math]EC_{inner}\gt 0.08p[/math].

P<3

After using above cuts the number of entries decreases ~46%

E total vs e inner1 before cuts file dst27070.gif E total vs e inner1 after cuts file dst27070.gif

0.5<P<1

The number of entries decreased by ~51.8%

E total vs e inner1 before cuts P1 file dst27070.gif E total vs e inner1 after cuts P1 file dst27070.gif

1<P<1.5

The number of entries decreased approximately by 47.8%

E total vs e inner1 before cuts P1.5 file dst27070.gif E total vs e inner1 after cuts P1.5 file dst27070.gif

1.5<P<2

In this case the number of entries decreased by 46.1%

E total vs e inner1 before cuts P2 file dst27070.gif E total vs e inner1 after cuts P2 file dst27070.gif

2<P<2.5

In this case the number of entries decreased by 38%

E total vs e inner1 before cuts P2.5 file dst27070.gif E total vs e inner1 after cuts P2.5 file dst27070.gif

P>3

Used file dst27070(Energy 5.735 GeV and Torus 2250) and are applied the following EC cuts: For ECtotal - [math]EC_{tot}\gt 0.24p[/math], for EC inner - [math]EC_{inner}\gt 0.06p[/math].

The number of entries decreased by~40.2%

E total vs e inner1 before cuts P3 file dst27070.gif E total vs e inner1 after cuts P3 file dst27070.gif

Plot of EC_tot/P vs nphe for Electrons

Used file dst27070(Energy 5.735 GeV and Torus 2250)

p<3 GeV
Does the graph below only contain electrons?  I assume so just restate it here for clarity.  At the bottom of this 
section you have plots for pions and electrons side by side.  Move those to the pion section below.  Does this 
mean there are a lot of pions mis-identified as electrons?



Dr. Forest, the graph bellow does not contain only electrons, there should be some contamination, because I have just 
 p<3 GeV cut.

E total vs nphe momentum cut file dst27070.gif

p<3 GeV and [math]EC_{inner}\gt 0.08p[/math]

E total P vs nphe momentum Ec inner cuts file dst27070.gif

p<3 GeV, [math]EC_{inner}\gt 0.08p[/math] and [math]EC_{tot}\gt 0.2p[/math]

E total P vs nphe momentum EC inner EC total cuts file dst27070.gif

p<3 GeV, [math]EC_{inner}\gt 0.08p[/math], [math]EC_{tot}\gt 0.2p[/math] and nphe>2.5
 Dr. Forest , in this case I applied all cuts as you see.

E total P vs nphe momentum EC inner EC total nphe cuts file dst27070.gif


The first histogram is for electrons and the other one for pions

E total vs nphe electrons file dst27070.gif

Pion

Summary Table

Tamuna:  
The pion id code is at:

http://www.jlab.org/Hall-B/secure/eg1/EG2000/josh/pion.cc

There are two subroutines, one which uses a constant cut for every paddle, 
one that has a different cut for every paddle.  The only other requirement 
is that the particle be produced with an angle less than 48 degrees in the 
 lab (so as to miss the magnet can).  The requirment that the pion fail the 
electron cut is not written in stone.  I still haven't checked to see the 
effects of it.

 Dr. Forest: I saw the pion id code. They have variables like start_time
and path_length. I do not know how define them. What should i use for
start time.


Beam Energy Torus Current Begin Run End Run file used cuts # trig([math]10^6[/math]) expected # evts([math]10^6[/math]) p>3,[math]EC_{tot}\lt 0.2*p [/math],[math] EC_{inner}\lt 0.08*p[/math](%) p<3,[math]EC_{tot}\lt 0.24*p [/math],[math] EC_{inner}\lt 0.06*p[/math](%)
[math]EC_{tot}\gt 0.2*p[/math] [math]EC_{inner}\gt 0.08*p[/math] [math]EC_{tot}\gt 0.2*p [/math] and [math] EC_{inner}\gt 0.08*p[/math]
1606 1500 25488 25559 dst25504_02.B00 60 3.2
1606 1500 25669 25732 dst25669_02.B00 226 10
1606 1500 25742 26221 dst25754_02.B00 3154 13.3
1606 -1500 26222 26359 dst26224_02.B00 703 13.1
1724 -1500 27644 27798 dst27649_02.B00 211 20
2288 1500 27205 27351 dst27225_02.B00 1647 16.1
2562 -1500 27799 27924 dst27809_02.B00 1441 13.1
2562 -1500 27942 27995 dst27942_02.B00 841 32.3
2562 1500 28001 28069 dst28002_02.B00 1013 30.7
2792 -1500 27936 27941 dst27937_02.B00 % 69 20.6
4239 2250 28074 28277 dst28075_02.B00 % % % 2278 19.6
4239 -2250 28280 28479 dst28281_02.B00 % % % 2620 15.2
4239 2250 28506 28510 dst28509_02.B00 % % % 75 18.1
5627 2250 27356 27364 dst27358_02.B00 % % % 56 19.4 36.1 31.5
5627 -2250 27366 27380 dst27368_02.B00 % % % 130 25 43.8
5627 2250 27386 27499 dst27388_02.B00 % % % 1210 20.2 39.8 32.4
5735 -2250 26874 27068 dst26904_02.B00 % % % 1709 19.9 22.5 46.4
5735 2250 27069 27198 dst27070_02.B00 % % % 1509 15 34.6 32.9
5764 -2250 26468 26722 dst26489_02.B00 % % % 1189 10 25.2 44.3
5764 -2250 26776 26851 dst26779_02.B00 % % % 662 15.9 21.3 44

Quality Checks

Rates

Asymmetries

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