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Run 13 W Test analysis : Study on Track duplicates , Track Splitting in tracking algorithm used for W analysis

Updated on Wed, 2016-05-04 20:49. Originally created by devika on 2016-04-22 14:52. 
 Study on Track duplicates , Track Splitting in STI , STICA from W analysis
Track selection and Track Matching method in  W algorithm 
We use following track selection Cuts in in W algorithm,

1.Nhits_min =>15
2.nHitsFit/nHitsPossible > 0.51
3.R of the nearestHit < 90 cm
4.R of the furthestHit > 160 cm
5. Pt > 10 GeV

All the primary tracks from the primary vertex which passed above cuts are extended to a calorimeter tower and then they are matched to a 2x2 Energy cluster. 
We do not place any cut to select a single track matching to a single calorimeter tower.  Once the tracks are matched with Max 2x2 cluster Et surroding the center matched tower. Following cuts are placed at track-cluster matching.

1. 2x2 Et > 15 GeV
2. DeltaR (track-cluster center) < 7 cm. 

Next we use two isolation requirements. 

1. 2x2_Et / 4x4 Et > 0.95
2. 2x2_Et / nearCone [0.7radius] > 0.88



Duplicate Tracks




Track Splitting :
Split tracks are cases where the point-to-point fluctuations in the hit locations associated with one true particle end up producing two or more
reconstructed tracks.  A simple example relevant for our TPC (but by no means the only situation where this happens) involves cases where a single
particle trajectory that crosses between two sectors gets reconstructed as two separate tracks.  In general, this happens all the time in track finders. 
Sti will only assign a hit to a single track.  Thus, when a track is split, at most one daughter will satisfy the standard nHitsFit/nHitsPossible > 0.51 cut.


Distributions of Final W tracks per event
Following Distribution shows the # of final W tracks after all the selection cuts applied per Event. Simply Event ID (tracks per event) is filled in to a 1D histogram at the end of the W section algorithm.

STI is tested using evals1.
I found 23 events with 2 W tracks (0.2 % ) while all others are singel W tracks. To see if these two tracks come from "duplicate tracks"  / "tracks splitting " or from two actual W particles I printed out the BEMC  tower ID of the tracks which are pointed to.  

pdf : 
csv



My understanding is that, 
If the 2 tracks are duplicate then they should pointed to the same BEMC tower.  [will pass all W cuts]
If the 2 tracks are splitted tracks belongs to single particle then they would have pointed to the close BEMC tower. [ most likely only the track belongs to the particle which make the EMC shower will pass  W isolation cuts]
If the 2 tracks are from 2 actual W there it is not necessray those two tracks to pointed to close EMC towers.


Below is the list of event ID which shows  2 final W tracks and the tower ID of the tracks are pointing:

eventID 4094 pointTowerId 4273
eventID 4094 pointTowerId 3457
eventID 8792 pointTowerId 497
eventID 8792 pointTowerId 4557
eventID 60256 pointTowerId 709
eventID 60256 pointTowerId 2427
eventID 138208 pointTowerId 4354
eventID 138208 pointTowerId 4713
eventID 139082 pointTowerId 444
eventID 139082 pointTowerId 532
eventID 144429 pointTowerId 2446
eventID 144429 pointTowerId 1404
eventID 183146 pointTowerId 4775
eventID 183146 pointTowerId 2699
eventID 232480 pointTowerId 229
eventID 232480 pointTowerId 1172
eventID 292282 pointTowerId 3052
eventID 292282 pointTowerId 2463
eventID 293107 pointTowerId 3461
eventID 293107 pointTowerId 3568
eventID 297779 pointTowerId 1333
eventID 297779 pointTowerId 4758
eventID 326929 pointTowerId 745
eventID 326929 pointTowerId 1516
eventID 373833 pointTowerId 4277
eventID 373833 pointTowerId 2757
eventID 381220 pointTowerId 1552
eventID 381220 pointTowerId 1137
eventID 407860 pointTowerId 2004
eventID 407860 pointTowerId 177
eventID 418100 pointTowerId 248
eventID 418100 pointTowerId 3441
eventID 466453 pointTowerId 904
eventID 466453 pointTowerId 1476
eventID 467908 pointTowerId 1751
eventID 467908 pointTowerId 3568
eventID 532317 pointTowerId 779
eventID 532317 pointTowerId 2483
eventID 626755 pointTowerId 2745
eventID 626755 pointTowerId 631
eventID 650023 pointTowerId 1201
eventID 650023 pointTowerId 1919
eventID 650906 pointTowerId 4436
eventID 650906 pointTowerId 2174
eventID 922250 pointTowerId 1411
eventID 922250 pointTowerId 3470
 
Based on this results I found NO duplicate tracks In STI.
My understanding is that above 23 events with 2 tracks are events with two true W particles.


STICA  is tested using evals4.
I found 40  events (0.34% ) with 2 W tracks, while all others are singel W tracks. To see if these two tracks come from "duplicate tracks"  / "tracks splitting " or from two actual W particles I printed out the BEMC  tower ID of the tracks which are pointed to.
pdf :
csv


eventID 2481 pointTowerId 1319
eventID 2481 pointTowerId 2603
eventID 4094 pointTowerId 4273
eventID 4094 pointTowerId 3457
eventID 25291 pointTowerId 3792
eventID 25291 pointTowerId 3707
eventID 40214 pointTowerId 4523
eventID 40214 pointTowerId 3725
eventID 49211 pointTowerId 2239
eventID 49211 pointTowerId 2113
eventID 70789 pointTowerId 180
eventID 70789 pointTowerId 3389
eventID 138208 pointTowerId 4354
eventID 138208 pointTowerId 4713
eventID 139082 pointTowerId 444
eventID 139082 pointTowerId 532
eventID 144428 pointTowerId 2446
eventID 144428 pointTowerId 1404
eventID 150880 pointTowerId 1451
eventID 150880 pointTowerId 4377
eventID 179055 pointTowerId 353
eventID 179055 pointTowerId 1465
eventID 183799 pointTowerId 498
eventID 183799 pointTowerId 41
eventID 200640 pointTowerId 2984
eventID 200640 pointTowerId 2846
eventID 214463 pointTowerId 3114
eventID 214463 pointTowerId 2015
eventID 229293 pointTowerId 4098
eventID 229293 pointTowerId 16
eventID 232480 pointTowerId 229
eventID 232480 pointTowerId 1172
eventID 292282 pointTowerId 3052
eventID 292282 pointTowerId 2463
eventID 293107 pointTowerId 3461
eventID 293107 pointTowerId 3568
eventID 297064 pointTowerId 4712
eventID 297064 pointTowerId 3477
eventID 297779 pointTowerId 1333
eventID 297779 pointTowerId 4758
eventID 326929 pointTowerId 745
eventID 326929 pointTowerId 1516
eventID 348540 pointTowerId 695
eventID 348540 pointTowerId 2574
eventID 357290 pointTowerId 731
eventID 357290 pointTowerId 2132
eventID 373833 pointTowerId 4277
eventID 373833 pointTowerId 2757
eventID 381220 pointTowerId 1552
eventID 381220 pointTowerId 1137
eventID 407860 pointTowerId 2004
eventID 407860 pointTowerId 177
eventID 416844 pointTowerId 23
eventID 416844 pointTowerId 2862
eventID 418100 pointTowerId 248
eventID 418100 pointTowerId 3441
eventID 466453 pointTowerId 904
eventID 466453 pointTowerId 1476
eventID 467908 pointTowerId 1751
eventID 467908 pointTowerId 3568
eventID 478290 pointTowerId 441
eventID 478290 pointTowerId 351
eventID 483478 pointTowerId 2202
eventID 483478 pointTowerId 4775
eventID 518583 pointTowerId 3129
eventID 518583 pointTowerId 698
eventID 611085 pointTowerId 4352
eventID 611085 pointTowerId 4726
eventID 626755 pointTowerId 2745
eventID 626755 pointTowerId 631
eventID 650906 pointTowerId 4436
eventID 650906 pointTowerId 2174
eventID 673281 pointTowerId 4131
eventID 673281 pointTowerId 253
eventID 852463 pointTowerId 2509
eventID 852463 pointTowerId 4468
eventID 922250 pointTowerId 1411
eventID 922250 pointTowerId 3470
eventID 1063037 pointTowerId 1723
eventID 1063037 pointTowerId 2719


Based on this results I found NO duplicate tracks In STICA.
My understanding is that above 40 events with 2 tracks are events with two true W particles.





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