The STAR experiment

This page compares the new tower calibration performed using only electron E/p to the calibration using last year's algorithm.  The two calibrations are found to be consistent within 120 MeV in E_T.

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• Feb 12, 2007
• Will, run7 plans,
  
• Will, Jan, Endcap startup plan
• L2 algos plan: Upsilon+displVartex (by Pibero), modified L2gamma (by Saski & Jason),  L2pedMon (by Jan) . some links , not much time to implement
• Jason, pi0 from Endcap from 2006 data, efficiency is low
• Will, BPRS-East gross mapping problem found, plan to replay data w/ all known corrections.
• Scott, Endcap calibration, MIP peak seen in towers, pre,post

• Feb 5 2007
• Rory, progress in BPRS mapping
• Adam, in-software mapping correction code
• Will, all, 2007 trigger discussion and  Steve
• Jan, electrons in the Endcap in 2006 data
• Pibero, eta dependence of reco pi0 invM for simu for Endcap

• Jan 29, 2007
• Oleg, Barrel electronics
• Jason, new display of Endcap points,clusters , code & writeup will be in CVS soon, needs special TTree as input
• Jan, embedding of  TPC+EMC is working, but ... needs 600MB for execution, code in CVS, awaits perr reviue
• Murrad, off-line jet phi anizotrophy for B & E-emc JP triggers
• Will, BPRS, suggested correlation between towers & pre-shower swaps, Rory got code from Adam for tracking toward BTOW
• Scott, ESMD calibration ready for DB upload, only slopes are used, flavor='slopes'

• Jan 22, 2007
• Murrad, offline jet phi,eta spetra
• Will, EMC fast to L2
• many: cray for Endcap off-line calibration

• Dec 18, 2006
• Jan, TPC+Endcap embedding
  is operational for pp2006 chain, missing writup, peer review, few
  tricks are needed to run it, ready for teasting of algo not for physics
• Adam, run dependence of MIP peak for BTOW shows jump on day 114+5, 5% trend for days 120-170
• Scott, Endcap 2006 calibration will be done, status: collecting muDst on the disk
• Will, explained most of the BPRS mapping problems as hadrware swaps, photos of hadrware illustrate the causes
• Naresh, summary of e/h discrimination in the Endcap (ppt) using TPC, dEdx,E/P, and postE, current contamination 14/1, run out of time

• Dec 11,2006
• Wei Ming, evaluation of Endcap pi0 efficiency w/ embedding,
• Jason, M-C e- tracking has eff=~80% for eta<1.6 
• Jason, Beam background in Endcap
  not seen in 2006, for both: clusters alone & clusters matched
  to Pibero's stright through tracks (flag=901)  
• Adam, ofl-onl BTOW gains, 136 more towers lost mainly due to the isloation cut
• Rory, BPRS mapping, identified miss-match patterns: +20 towers, backward mapping Y=-X

 

Endcap Sofware  2006++

 

Instructions

The following topics were pending from the previous meeting and needed follow-ups

1. Tripwire versus AIDE + real evaluation of tripwire impact
   
2. Shift signup: provision for more than one Email address per institution

Time	Talk	Presenter
14:00	Purchase status ( 00:10 ) 0 files	All
14:10	Pending issues, round table ( 00:10 ) 0 files	All
14:30	SSH key management, last call for model change ( 00:10 ) 1 file	Jerome Lauret (BNL)

This is CSMStatusUtils, which outputs the status of either calorimeter to text and root status files.  Documentation is by Dave Relyea.  The code can be found at

Second most important step in EMC data reduction is to find clusters from EMC data.

Main code performing EMC clustering is located in StRoot/StPreEclMaker and StRoot/StEpcMaker

This page gives a brief overview of the code Frank Simon developed to create SMD Status Tables from MuDSTs.

Trash pages for testing

Steve's caiibrations page contains most of the details:

http://www.star.bnl.gov/protected/spin/trent/calibration/calibration.html

I decided not to correct for SpaceCharge and GridLeak in the 62GeV p+p dataset from 2006. This decision was based on the following points. Note that the plots are from some of the early production of P06ie (the conclusions were made from a smaller pre-production sample, but I could make the plots with better statistics from the production).

Signed DCA

Signed DCA profile versus BBC sum (east+west), where the red markers are from using east-TPC-only tracks, blue is west-TPC-only, and black is all tracks combined:

Some observations:

• The lowest luminosity bin does not fit the pattern of the higher luminosity data (it seems to have only small distortions, which is what we would like to see!).
• For the rest, there appears to be some luminosity dependence, and it goes it the correct direction for this field (negative slope for positive field).
• The east and west TPC are offset from each other. My first guess on this was that the You do not have access to view this node wasn't doing it's job so well on the east, and this was causing a shifted sDCA. But other east-west differences show up (see the next section) which hint that the shorted ring may not be the problem.
• The overall effects are small, with sDCA values generally of a few hundred microns. A plot of the track-by-track sDCA can be found here, and I estimate that overall the sDCA is offset from zero by about 300-400 microns, with an RMS of about 500 microns (due to the luminosity range).

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Residuals

Global track residuals at low (left, BBC sum < 1e5) and high (right, BBC sum > 1.5e5) luminosities versus Z and padrow:

Key points:

• These distortions are quite small, producing residuals in the range of 100-200 microns.
• There is a notable east-west difference, and the distortions appear to be almost non-existent in the west. Some east-west differences have been observed in the past, but were atop a much larger distortion, and were considered not worth worrying about.
• Almost no z-dependence is at odds with our correction model.
• The high luminosity data appears less distorted than the low luminosity (which agrees with the sDCA plots above). Could it really be that what I am labeling as low luminosity (low BBC sum rate) is actually more distorted? Perhaps some backgrounds existed during the periods of low luminosity data, which went away during the periods of higher luminosity (which tended to be earlier during the 62 GeV running).

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Summary

First, it is worthwhile to note that our ionization distortion correction machinery is not set up for east/west differences. Using a sagitta error of 400+/-500 microns, here is the estimated error in transverse momentum reconstruction of primary tracks, in delta Pt / Pt^2 (fractional momentum error per GeV/c of momentum):

We can see that we expect something like an error pf 0.33% per GeV/c of Pt. This corresponds to an average error of 3 MeV/c on a Pt = 1 GeV/c track, and about 85 MeV/c on a 5 GeV/c track (with fluctuations of about +/-100 MeV/c from the mean). There are less than 20 million events with TPC information in this pp62 dataset (mostly the "mb" trigger). This will statistically limit any analyis from high-pt studies, precluding the need to have the data calibrated to higher precision than already exists in this uncorrected data.

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Gene Van Buren

I've updated my codes to do a more systematic investigation of the stability of the gains.  Instead of trying to get sufficient tower-by-tower statistics for different time periods, I'm looking at MIP peaks for single runs integrated over all towers.  Here's the plot:

Simulation of HBT effect from the daughter lambdas of sigma's or xi's, as shown in the graphs.

The charge to the Review Committee for evaluation of the HFT proposal is archived here. The online document can be found under http://hepwww.physics.yale.edu/star/upgrades/Draft-Charge.pdf