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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.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
![](/STAR/system/files/cfactors.png)
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:
![](/STAR/system/files/xsec.png)
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.
2005 Charged Pion Data / Simulation Comparison
Updated on Thu, 2007-10-18 09:50. Originally created by kocolosk on 2006-06-21 21:57.Estimates of trigger bias systematic error are derived from simulation. This page compares yields obtained from data and simulation to test the validity of the PYTHIA event generator and our detector geometry model.
Conditions:
- Simulation DB timestamp: dbMk->SetDateTime(20050506,214129). I pick this table up from the DB, rather than from Dave's private directory. Dave changed the timestamps on the files in his directory, so the two files do not match. It turns out that in this case they only differ by one tower (4580), and this tower's status is != 1 in both tables, so there is effectively no difference.
- Data runlist: I use a version of the jet golden run list containing 690 runs. I have heard there is an updated version floating around, but I have yet to get my hands on it
- Simulation files obtained from production P05ih, including larger event samples from Lidia's recent email (http://www.star.bnl.gov/HyperNews-star/protected/get/starsoft/6437.html) but excluding the 2_3, 45_55, and 55_65 GeV samples.
- This is strictly a charged hadron comparison, there is no dE/dx PID cut. The dE/dx dsitributions in simulation are way off.
- Cuts: nFitPoints>25 && |dca|<1. && |eta|<1. && |vz|<60. && pt>2. Also for data I require good spin info and relative luminosity information (these conditions are mostly subsumed by the runlist requirement).
Combine PYTHIA partonic pt samples by filling histograms with weight = sample_weight/nevents, using sample_weights
- 3_4 = 1.287;
- 4_5 = 3.117e-1;
- 5_7 = 1.360e-1;
- 7_9 = 2.305e-2;
- 9_11 = 5.494e-3;
- 11_15 = 2.228e-3;
- 15_25 = 3.895e-4;
- 25_35 = 1.016e-5;
- above_35 = 5.299e-7;
Results:
At the moment I've just linked the raw PDFs at the bottom of the page. The index in the title indicates the charge of the particle being studied. The plots are perhaps a bit hard to follow without labels (next on the list), so here's a guide. Page 1 has pt distributions for the triggers in the order listed above. Pages 2-6 are eta distributions, with each page devoted to a single trigger, again in the order given above. The first plot on each page is integrated over all pt, and then the remaining plots separate the distribution into 1 GeV pt slices. Pages 7-11 repeat this structure for phi, and 12-16 do the same for the z-vertex distributions.
Conclusions:
The agreement between data and simulation appears to be me to be quite good across the board. The jet-patch triggers are particularly well-modeled. A few notes:
- The HT2 pt distributions (page 1, third plot on top row) look funny in simulation. What's with the spike at 6 GeV in the h- plot?
- HT2 eta distribution on the east side for h+ (page 4) has spikes.
- Phi looks good to me
- Vertex distributions for calo triggers in simulation are awfully choppy, but overall the agreement seems OK.
Vertex Finding Investigations
Updated on Tue, 2006-03-28 07:36. Originally created by lbarnby on 2006-03-28 07:36.Plan for improving vertex finding in Cu+Cu
Anthony looking at ways of telling whether vertex is likely to be the correct one based on event info: ZDC, (apparent) reference multiplicity, CTB sum (correlations between these)
Star Analysis Meeting Dec 3-5, 2005
Updated on Tue, 2005-12-06 09:03. Originally created by pruneau on 2005-12-04 22:24.File Catalog Distribution/Replication (phase one: Grid - work around)
Updated on Fri, 2005-11-04 11:35. Originally created by deph on 2005-11-04 10:26.MySQL replication will be used, initially to provide a complete file catalog at each of the sites. The challenge is that each sit will be able to update this catalog, so this information needs to be centrally aggregated and then redistributed to each site as a complete/comprehensive database.
pp400 Calibrations
Updated on Mon, 2005-10-24 14:07. Originally created by genevb on 2005-10-24 12:05.My current calibration priority is to finish pp400 data. The BeamLine constraint calibration was already done for this data, and no static distortions should be any different from the rest of the pp200 run.
Discussions on StDbLib
Updated on Tue, 2005-10-11 12:32. Originally created by deph on 2005-10-11 12:23.The offline database API is a topic of discussion. This BLOG is to enhance understanding, generate documentation, record ideas and present possible improvements for review.