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Ali Hanks Group Meeting Sep. 25, 2006. Measuring bremsstrahlung photons in pp collisions. Outline/Methodology. Method: select g dir associated with high p T hadron using correlations 1 st Step: construct hadron- g inc correlation functions
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Ali Hanks Group Meeting Sep. 25, 2006 Measuring bremsstrahlung photons in pp collisions Group Meeting
Group Meeting Outline/Methodology • Method: select gdir associated with high pT hadron using correlations • 1st Step: construct hadron-ginc correlation functions • 2nd Step: remove background from decay photons • construct hadron-gtagged correlations from 0 decays • estimate tagging efficiency as a function of and pT using fastmc • use corrected hadron-g0 to estimate the total hadron-gdec contribution • 3rd Step: calculate gfrag yield from resulting h-gdir correlation
h-ginc per trigger yield Group Meeting
h-gtagged per trigger yield • fg gtagged • bg gtagged Group Meeting
h-gtagged per trigger yield • With combinatorial background subtracted Group Meeting
h-gsubtracted per trigger yield • h-ginc – h-gtagged as a first try at subtracting decay contribution Group Meeting
Tagging efficiency • ginc • fg gtag • bg gtag • ginc • gtag Group Meeting
Invariant mass fg/bg • fg gtagged • bg gtagged Group Meeting
p0 trigger hadron- ∆ distribution single acc pair acc ∆ Tagging efficiency • Simulation generates p0s in a guassian distribution around a “trigger” hadron • distribution is pT dependant • determined from real data • Let these p0s decay and compare resulting h-g Df distribution for single photon acceptance and pair acceptance Group Meeting
Tagging efficiency pT < 3.5 GeV/c ∆ Tagging efficiency pT > 6 GeV/c Tagging efficiency 4 < pT < 4.5 GeV/c ∆ ∆ Tagging efficiency estimates • Study tagging efficiency as a function of Df in several pT bins • Still need to do this with input p0 spectrum from pp and run 5 acceptance Group Meeting
To Do • Complete work on subtraction of h-gdecay • errors in calculation of combinatorial background for tagging p0 decay photons • esitmate of tagging efficiency using fastmc still in early stages • contribution from other hadronic decays • Still not clear if shape is same as for g0 Group Meeting
Hot tower Maps • hot towers for cluster with pT from 1-2 GeV/c Group Meeting
Hot tower Maps • hot towers for cluster with pT from 2-3 GeV/c Group Meeting
Hot tower Maps • hot towers for cluster with pT from 3-20 GeV/c Group Meeting
Backup – tagging efficiency • Input p0 distribution with gaussian around trigger larger than acceptance Group Meeting