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Nose-Cone Calorimeter: A LL Study of γ -J et QCD Processes:Plan

Nose-Cone Calorimeter: A LL Study of γ -J et QCD Processes:Plan. Astrid Morreale University Of California Riverside July 26, 2004. γ. g. q/qbar. q/qbar. jet. Gamma-Jet Physics. Assuming minimum photon p T =5GeV Central arm only(  =0): X 1 ~X 2 ~ 0.05, Q 2 ~10 2 -10 3

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Nose-Cone Calorimeter: A LL Study of γ -J et QCD Processes:Plan

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  1. Nose-Cone Calorimeter: ALL Study of γ-Jet QCD Processes:Plan Astrid Morreale University Of California Riverside July 26, 2004

  2. γ g q/qbar q/qbar jet Gamma-Jet Physics Assuming minimum photon pT=5GeV • Central arm only(=0): X1 ~X2 ~ 0.05, Q2~102-103 • Central arm + forward: X2 ~ 0.025, X1~0.52, Q2~103 • Both in forward(=3): X2~0.0025, X1~1.0, Q2~102-103 DIS experiment measurement QCD

  3. Things to Consider: 1. Signal: Photons from photon-jet event. • Background: -Decay photons from 2-Jet events, i.e. πº ----> 2γ (physics’s most important background compare to others if there’re any.) -Artificial background e.g. -fake jet reconstruction.(response level) -fake gamma identification from electron • Separate PYTHIA Simulations to be Generated for different backgrounds 1.

  4. Response Level Pythia PISA 2. Quantify signal efficiency and background rejection: -Simulate detector response -Apply analysis cuts. -Implement jet-finding algorithm 3. Determine remaining yield for signal and background. • Calculate the absolute yield for expected luminosity • Convolute with efficiency:σ(γ+jet)•I, where I~234pb¯¹(run8) • Ntot Total Yield for signal and background: eff• σ(γ +jet)•I Eff is obtained by calculating how much of the signal and background are contained in the total numbers of events initiated in Pythia RHIC Collider Projections (FY2005-FY2008) T.Roser, W.Fisher M. Bai, F. Pilat. (page 10) Get cross sections from Pythia's prediction

  5. 4. Proposed Scheme • ALL= (N++- N+-)/(N+++N+--)--------> N++/N+-= (1+ALL)/(1-ALL) . • N++= [(1+ALL)/2]•Ntot • N+-= [(1-ALL)/2]•Ntot, where Ntot is N+++N+- • ALL is partonic level asymmetry and needs to be calculated, see next page • ΔNbgrnd = (N++- N+-)bgrnd, • ΔNsignal = (N++- N+-)signal ALL(measurement) = (ΔN (signal) + ΣΔN(bgrnd))/( Ntot(signal)+Ntot (bgrnd))

  6. 5. QCD Calculations and Experimental Observables ALL (γ+jet) vs: • PT ( jet) • PT(prompt\ γ) • PT(jet)+PT(prompt γ) • opening angle γ +jet Werner Vogelsang(?)or Dave Kawall(?) will do the QCD calculation of partonic- level asymmetry ALL(background (two-jet, etc)) vs: • PT ( jet) • PT (decay\ γ from πº) • PT(jet) +PT(decay\ γ) • PT-opening angle(γ decay +jet)

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