The STAR experiment

I wrote a script that compares each Run 7 BTOW pedestal table with a corresponding L2ped printout. The script queries the RunLog_onl database for the runnumber immediately preceding the table timestamp, then it looks for a log file corresponding to that runnumber in the L2ped directory on online.star.bnl.gov. If it can’t find the precise runnumber, it compares the online pedestals to the next closest L2ped runnumbers both before and after, and then prints the comparison for the better match.

Here’s a summary log printing the number of channels per table where

1. the difference in pedestal value is greater than 4, or
2. the difference in pedestal sigma is greater than 1.5

There are a handful of channels per run with drastic differences. For example, emcOnline will declare a zero pedestal, but l2ped will say there’s a peak at 3500 ADCs. Channels like these are obviously bad. Of greater concern are the runnumbers where several hundred channels do not match. Most of the time it’s because the widths are different, but occasionally there are runs where a few hundred towers will have pedestals that differ by more than 4 ADCs. The full verbose output (listing every tower that fails the cut) can be found here.

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In
this update
a set of results with Adam's suggested momentum cut is added to the pool of analysis results for d+Au.

I've been working with Priscilla on adding her electron candidates to the spin trees.  spinTrees with electrons are now available, and we went ahead and made these plots investigating the properties of jets with identified electrons.  We analyzed BJP1 and L2Gamma triggers and plotted the p_T spectra, track multiplicity, and neutral energy fraction for all jets and for jets associated with an electron candidate (deltaR < 0.7).  Full-size plots available by clicking on each image.

Electron Cuts

• Global dE/dx cut changing with momentum
• nFitPoints >= 15
• nDedxPoints >= 10
• nHits / nPoss >= 0.52
• track Chi2 < 4
• DCAGlobal < 2
• NEtaStrips > 1 && NPhiStrips > 1
• Primary dE/dx cut changing with momentum
• 0.3 < P/E < 1.5
• -0.01287 < PhiDist < 0.01345
• ZDist in [-5.47,1.796] (West) or [-2.706,5.322] (East)

Jet Cuts

• 0 < R_T < 0.99
• -0.7 < detEta < 0.9
• Jet points at fired jet patch (BJP1 only)

Conclusions

• The neutral energy fraction for L2gamma electron jets peaks at the same point as the ridge in the inclusive jet plot.
• There are a significant number of 1-track jets in the L2gamma sample
• In the plot of jet p_T vs. electron p_T we see the maximum of the distribution occurring at a electron pT of ~5.5 GeV and a jet pT of ~11 GeV.  This is in stark contrast to the BJP1 distribution. 

1. QA for BJP0 trigger and runlist generation
2. Confirm vertex and nSigma cuts with systematic studies
3. Run over new PYTHIA simulation, make basic data/simu comparisons
4. Trigger Bias studies
5. Extract A_TT from transverse data
6. Randomized spin pattern studies
7. PID background estimation

Notes

• Adding the L2gamma trigger would improve statistics but we don't have an officially sanctioned simulation of that trigger available yet.
• This checklist assumes the preliminary result is an inclusive measurement using only Run 6 data; other possibilities are to combine Runs 5 and 6 or to pursue the jet+pion measurement.

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