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Data - Monte Carlo Comparison, Take 2
Updated on Thu, 2007-10-18 08:23. Originally created by kocolosk on 2006-09-14 20:27. I re-examined the data - pythia comparison in my analysis after some good questions were raised during my preliminary result presentation at today's Spin PWG meeting. In particular, there was some concern over occasionally erratic error bars in the simulation histograms and also some questions about the shape of the z-vertex distributions.
Pointing Resolution plots
Updated on Mon, 2006-09-11 14:38. Originally created by wleight on 2006-09-11 14:02. These plots were made from 100 hijing events using perfect hits in the old three-layer IST and the HFT, but no SSD. Currently, it is not possible to make plots containing both the IST and the HFT as the bfc upgrade tags for the upgrade are upgr01, which contains the HFT and SSD but not the IST, and upgr02, which contains the HFT and IST but not the SSD.
Systematic Error Table
Updated on Thu, 2006-09-07 12:36. Originally created by kocolosk on 2006-09-07 12:36.I've included an Excel spreadsheet with currently assigned systematic errors as an attachment.
Background from PID Contamination
Updated on Thu, 2007-10-18 08:19. Originally created by kocolosk on 2006-09-06 17:50. Summary:
The goal of this analysis is to estimate the contribution to A_LL from particles that aren't charged pions but nevertheless make it into my analysis sample.
Asymmetries for near-side and away-side pions
Summary:
I associated charged pions from JP2 events with the jets that were found in these events. If a jet satisfied a set of cuts (including the geometric cut to exclude non-trigger jets), I calculated a deltaR from this jet for each pion in my sample. Then I split up my sample into near-side and away-side pions and calculate an asymmetry for both samples.
Random Patterns
Updated on Thu, 2007-10-18 08:10. Originally created by kocolosk on 2006-08-07 08:50. Triggers are
| mb | ht1 |
| ht2 | jp1 |
| jp2 | all |
| mb | ht1 |
| ht2 | jp1 |
| jp2 | all |
Inclusive Charged Pion Cross Section - First Look
Updated on Thu, 2007-10-18 09:52. Originally created by kocolosk on 2006-08-03 12:55. Correction factors are derived from simulation by taking the ratio of the reconstructed primary tracks matched to MC pions divided by the MC pions. Specifically, the following cuts are applied:
Monte Carlo
Matched Reco Tracks
There is currently a bug in StDetectorDbMaker that makes it difficult to retrieve accurate prescales using only a catalog query for the filelist. This affects the absolute scale of each cross section and data points for HT1 and JP1 relative to the other three triggers. It's probably a 10%-20% effect for HT1 and JP1. With that in mind, here's what I have so far:
This plot is generated from a fraction of the full dataset; I stopped my jobs when I discovered the prescales bug.
The cuts used to select good events from the data are:
The cuts used to select pion tracks are the same as the ones used for "Matched Reco Tracks", except for the PID cut of course. For PID I require that the dE/dx value of the track is between -1 and 2 sigma away from the mean for pions.
As always, comments are welcome.
Monte Carlo
- |event_vz| < 60.
- |eta| < 1.
- nhits > 25
- geantID == 8||9 (charged pions)
Matched Reco Tracks
- |event_vz|<60.
- |reco eta| < 1.
- |global DCA| < 1.
- reco fit points > 25
- geantID of matched track == 8||9
There is currently a bug in StDetectorDbMaker that makes it difficult to retrieve accurate prescales using only a catalog query for the filelist. This affects the absolute scale of each cross section and data points for HT1 and JP1 relative to the other three triggers. It's probably a 10%-20% effect for HT1 and JP1. With that in mind, here's what I have so far:
This plot is generated from a fraction of the full dataset; I stopped my jobs when I discovered the prescales bug.
The cuts used to select good events from the data are:
- golden run list, version c
- |vz| < 60.
- Right now I am only using the first vertex from each event, but it's easy for me to change
The cuts used to select pion tracks are the same as the ones used for "Matched Reco Tracks", except for the PID cut of course. For PID I require that the dE/dx value of the track is between -1 and 2 sigma away from the mean for pions.
As always, comments are welcome.
Notes from spin pwg meeting 7/13/06
Updated on Thu, 2006-07-13 15:57. Originally created by jwebb on 2006-07-13 13:51.Notes from collaboration meeting
The following are notes I took during the STAR collaboration meeting at MIT, specifically the spin pwg session on 7/13/06. It's not an exhaustive summary,
since I'm just "kicking the tires" on drupal.
First Look at Charged Pion Trigger Bias
Motivation:
The charged pion A_LL analysis selects pions from events triggered by the EMC. This analysis attempts to estimate the systematic bias introduced by that selection.
Conditions:
- Simulation files, database timestamps, and selection cuts are the same as the ones used in the 2005 Charged Pion Data / Simulation Comparison
- Polarized PDFs are incorporated into simulation via the framework used by the jet group. In particular, only GRSV-std is used as input, since LO versions of the other scenarios were not available at the time.
- Errors on A_LL are calculated according to Jim Sowinski's recipe.
Plots:
Conclusion:
The BBC trigger has a negligible effect on the asymmetries, affirming its use as a "minimum-bias" trigger. The EMC triggers introduce a positive bias of as much as 1.0% in both asymmetries. The positive bias is more consistent in JP2; the HT2 asymmetries are all over the map.