Intent to Publish 2006 Gamma + Jet Cross Section



Gamma-jet cross sections for forward gammas in proton-proton collisions at root(s) = 200 GeV/c

Principal Authors (alphabetical order)

Keith Krueger (ANL), Hal Spinka (ANL), Dave Underwood (ANL)

Intended Journal

Physical Review D


A measurement is presented of the cross section vs. transverse momentum (pT) for gamma + jet production in proton-proton collisions. The data were measured in the STAR detector at RHIC at √s = 200 GeV/c. The jet was detected at central pseudorapidity (|η| < 0.8) and the γ at intermediate pseudorapidity (1.2 < η < 2.0). These regions were chosen to access lower x of the gluon relative to a central-pseudorapidity-only measurement, and also because a large partonic spin asymmetry, All, in the parton cm is selected. The technique of finding single γ’s in the background of photons from π0 decay is based on a standard chi-squared method for the shower shape in the shower maximum detector of an electromagnetic calorimeter.


  • Introduction
    • Refs. to earlier measurements and theory predictions
    • Connection to gluon distribution
  • Hardware
    • RHIC general (Refs.)
    • STAR general (Refs.)
    • TPC and BEMC for jets (Refs.)
    • EEMC and ESMD for gamma
    • trigger
    • luminosity
  • Analysis
    • Jets (Refs.)
    • Gammas with chi-squared (Ref.)
    • Efficiency / RooUnfold
    • Other Corrections?
    • Systematics
    • Table of results with errors
  • Results
    • Comparison to JETPHOX (Refs.)
    • Comparison to pi0’s?
  • Summary / Conclusions

Presentations to the Spin PWG (April 23)