Home » PANDA » PandaRoot » Tracking » One question about tracking efficiency
One question about tracking efficiency [message #10560] |
Wed, 21 April 2010 17:51 |
Yutie Liang
Messages: 12 Registered: April 2010 Location: Germany
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occasional visitor |
From: *physik.uni-giessen.de
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Dear all,
I met one problem when I use the PandaRoot to do one simple study. The decay chain of my study is: Psi(3770) -> D+ D- ->(k- pi+ pi+)( k+ pi- pi-)
I simulated 10k signals, but only 300~400 events survived.
I think this efficiency is too low.
The following is the detailed infomation of one event from generator. TrackIDs of (k-, pi+, pi+, k+, pi-, pi-) are always (0,1,2,3,4,5). So, I use this trackID as PID in this study.
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0 9
N Id Ist M1 M2 DF DL px py pz E t x y z
0 40443 2 -1 -1 1 2 0.00000000 -0.00000000 6.57879835 7.58363969 0.00000000 0.00000000 0.00000000 0.00000
000
1 411 2 0 0 3 5 -0.02342460 -0.12417095 3.72753839 4.17190509 0.00000000 0.00000000 -0.00000000 0.000
00000
2 -411 2 0 0 6 8 0.02342460 0.12417095 2.85125996 3.41173460 0.00000000 0.00000000 -0.00000000 0.00000
000
3 -321 1 1 1 -1 -1 -0.41376210 0.45311777 0.95670547 1.23916104 6.38056669 -0.03582590 -0.18990870 5.700
94639
4 211 1 1 1 -1 -1 0.25929310 -0.57261601 2.59179905 2.67058498 6.38056669 -0.03582590 -0.18990870 5.700
94639
5 211 1 1 1 -1 -1 0.13104440 -0.00467271 0.17903387 0.26215907 6.38056669 -0.03582590 -0.18990870 5.700
94639
6 321 1 2 2 -1 -1 0.01936009 -0.00991458 0.09054525 0.50238581 1.18131702 0.00811080 0.04299434 0.98725
203
7 -211 1 2 2 -1 -1 0.24342156 0.42046406 1.79061469 1.86059797 1.18131702 0.00811080 0.04299434 0.987252
03
8 -211 1 2 2 -1 -1 -0.23935704 -0.28637852 0.97010002 1.04875082 1.18131702 0.00811080 0.04299434 0.9872
5203
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I checked, and found that the tracking efficiency of (k-, pi+, pi+, k+, pi-, pi-) is only about 50~60%, when MC trackID' match is required. this low efficiency of each track could explain the low efficiency of this channel.
but, when I did single track study, the tracking efficiency of pi+ with MCtrackID match is close to 80%. This is also low, but still acceptable considering McID match.
It seems that when there are multiple tracks, 6 in my case, the tracking efficiency will become worse. Is this the problem?
I hope that's only one bug of my analysis.
Thanks
yutie
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Re: One question about tracking efficiency [message #10567 is a reply to message #10565] |
Thu, 22 April 2010 11:26 |
StefanoSpataro
Messages: 2736 Registered: June 2005 Location: Torino
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first-grade participant |
From: *to.infn.it
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Hi,
I have found a bug in the EvtGen reader, that maybe could affect your analysis.
EvtGen manual says that the vertex position is expressed in mm, but PndEvtGenGenerator is giving the position to the VMC as cm.
I have modified PndEvtGenGenerator, to use is you should update your "pgenerator" folder, and then rerun your simulation (not evtgen, but from the "sim" macros up to the end).
This could exlain maybe your problem. In your event, particles 3 4 and 5 are emittet at 6 mm from the vertex, but if they are propagated as 6cm, then the track finder will fail.
In this case, you should modify in your sim macro:
FairEvtGenGenerator -> PndEvtGenGenerator
Could you please try and let me know if it improves your results?
Fair stays with the old code, while Pnd should be the fixed one.
(crossing our fingers).
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Re: One question about tracking efficiency [message #10574 is a reply to message #10567] |
Thu, 22 April 2010 14:42 |
Yutie Liang
Messages: 12 Registered: April 2010 Location: Germany
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occasional visitor |
From: *physik.uni-giessen.de
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Hi,
I tried with your new code, which I saw the conversion of cm/mm.
It does improve my result, but not very much.
I only tested with 200 events, and got 12 signals. I will test with more statistic later.
The total efficiency of this channel ~ 6%, is better than the former 3-4%. It's still too low.
I think there could be some other prolems.
I listed the tracks info of several events.
To survive the analysis program, the MctrackID should contain 0,1,2,3,4,5 at least. In the following, only event 194 passed this, but failed the mass cut.
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event: 194
mom: (-0.276957, 0.489483, 1.41229) MctrackID: 4
mom: (0.547624, -0.518, 1.18875) MctrackID: 3
mom: (4.74344, 1.18262, 3.54849) MctrackID: 2
mom: (1.73905, 0.298494, 2.67836) MctrackID: 2
mom: (-0.890036, -0.0107261, 1.80312) MctrackID: 1
mom: (-0.100752, -0.205479, 0.654262) MctrackID: 5
mom: (-0.127335, -0.0098834, 0.799576) MctrackID: 0
mass of dp: 5.29566
mass of dp: 3.10414
mass of dm: 1.78799
dp: 0 dm: 1
event: 195
mom: (-0.714914, -0.0269411, 0.979918) MctrackID: 4
mom: (0.779887, -0.125705, 1.85668) MctrackID: 3
mom: (0.259352, 0.166287, 1.226) MctrackID: 2
mom: (0.397058, -0.224433, 0.460777) MctrackID: 0
mom: (-0.0066277, -0.179322, 0.835163) MctrackID: 1
event: 196
mom: (0.757172, 0.107102, 1.45513) MctrackID: 5
mom: (-0.269729, -0.0472028, 0.835738) MctrackID: 4
mom: (-0.0532711, -0.646725, 1.03129) MctrackID: 0
mom: (1.77291, 2.69191, 3.89288) MctrackID: 2
mom: (0.625281, 0.877034, 0.994429) MctrackID: 2
mom: (-2.25023, -0.892301, 1.50073) MctrackID: 2
mom: (0.298023, 0.639753, 1.01819) MctrackID: 2
mom: (-0.176344, 0.110833, 0.639549) MctrackID: 4
mom: (-0.100674, -0.0839868, 0.826197) MctrackID: 1
event: 197
mom: (0.366878, -0.291604, 1.02965) MctrackID: 5
mom: (-0.346555, 0.366326, 0.323261) MctrackID: 4
mom: (0.0505044, -0.0861833, 0.401847) MctrackID: 1
mom: (5.3789, -1.86377, 11.1783) MctrackID: -1
event: 198
mom: (-0.346544, 0.413518, 1.98112) MctrackID: 3
mom: (0.0704105, -0.270733, 0.279589) MctrackID: 4
mom: (1.74562, 0.732808, 5.13812) MctrackID: 2
event: 199
mom: (-0.186931, -0.370772, 0.620371) MctrackID: 4
mom: (0.232215, -0.590434, 1.37189) MctrackID: 0
mom: (0.386676, 5.02008, 2.315) MctrackID: 5
event: 200
mom: (0.569166, 0.378718, 1.23879) MctrackID: 5
mom: (-0.406435, -0.291732, 1.41973) MctrackID: 4
mom: (-76.9758, -12.678, 384.064) MctrackID: 0
mom: (0.274015, 1.52483, 0.010232) MctrackID: 2
mom: (-0.126436, -0.296277, 0.736622) MctrackID: 3
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regards
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