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.
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 :
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:
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
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.
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.
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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