The STAR experiment

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

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. 

Features of the STAR Notes Module (drupal.star.bnl.gov/STAR/starnotes)

Geometry:

Description of the Drupal STAR Notes Module

Run 7 Calibrations

*** PMD
- Examination of days 89-121 (without tracking) in progress
    + Will spend the next couple weeks hammering out the gain calib process on this data