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Blessing of Run II Diffractive Results. Introduction Data Selection Plots for Blessing. Forward Physics. Hard Single Diffraction Double Pomeron Exchange …. Diffractive Dijets. Compare diffractive events to ND Measure diffractive structure function from R SD/ND vs x bj.
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Blessing ofRun II Diffractive Results • Introduction • Data Selection • Plots for Blessing M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Forward Physics • Hard Single Diffraction • Double Pomeron Exchange • … M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Diffractive Dijets • Compare diffractive events to ND • Measure diffractive structure function • from RSD/NDvsx bj Measure x (pbar momentum loss fraction) from calorimeter information M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
x : Momentum Loss Fraction Measure fractional momentum loss of anti-proton MX 2 x = s S ETe-h x = s Dy= ln (1/x) Diffractive events are boosted towards positive h small x M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Trigger • RP is triggered on leading antiprotons • Use RP + jet triggers require jets M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Data Sample • Use dedicated diffractive triggers • RP+J5 (diffractive sample) • J5 (control sample) • Data sample ~9 pb-1 (PHYSICS_1_03_v1) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Event Selection • Triggered events 352,359 • MET Significance<6 352,359 • Two jets (ET>5, |h|<2.5) 175,292 • RP coincidence 168,153 • SD (0.02< x<0.1) 15,209 • All BSC East Gap 1,126 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Question #4 Q : What is the ratio SD/ND for ET > 10 GeV ? M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
DSF with Jet ET cut ET1 + ET2 ET* = 2 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Q2 Dependence M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Answer to Q#4 Q : What is the ratio SD/ND for ET > 10 GeV ? A : Slope and normalization change by ~ 1% . M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Plots For Blessing Suggested modifications have been implemented M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
x Distribution M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Rapidity Run I PRL Diffractive dijets are boosted away from the recoil antiproton M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Mean Dijet ET M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Df (jet1-jet2) Diffractive dijets are more back to back M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
MP Multiplicity M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Diffractive Structure Function M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Diffractive Structure Function (II) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
East Multiplicity: BSC vs MP M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
DPE Enhanced Sample • Study a dedicated DPE trigger (RP+J5+GapE) • ~300 k events • ET(jet1,2)>5 GeV • |h(jet1,2(,3))|< 2.5 • (0,0) bin ~ 16,000 events (in Run I: 100 evts) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Df (jet1-jet2) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Dijet Mean Rapidity M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Jet Transverse Energy M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Conclusions Relax, it is only physics. M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Question # 1 Q : Is the BG peak at x ~ 1 due to overlap events from multiple interactions? M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
x Distribution M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Luminosity Dependence Luminosity: 1.0 E31 1.5 E31 2.3 E31 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Overlap Rate SD x MB overlap J5 x RP overlap sND (1 - e- n RP) + sSD (1 - e- n ) R (ND/SD) = sSD e- n SD surviving MB overlap • nRP= ( 1 mb/50 mb) x n , n = 0.3 x L[1 x E31] • sND / sSD ~ 600 R (ND/SD) = 12 n e n M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Multiple Interactions Shift ND Peak R vs log (1 + n ) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Run I vs Run II Run I Run II L um / bunch 0.16E30 / 6 20.0E30 / 36 sND / sSD 300 (lower jet ET) 600 R (Run I/Run II ) = 1/60 R (Run II) = 10 R (Run I) = 0.15 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Multiple Interactions M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Answer to Q# 1 Q : Is the BG peak at x ~ 1 due to overlap events from multiple interactions? • A : Yes. • Ratio is consistent with Run I numbers and Run II expectations. • Peak at x ~ 1 shifts according to luminosity, as expected. M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Question #2 Q : What is the effect of the MP energy scale calibration ? M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
MP Calibration • Use slope from ADC distribution • Tower-to-tower relative calibration with data/MC • Energy scale from MC • MC/MBR • Pile-up at high luminosity • (Slope-Fit)/Fit ~7% for each ring • Time dependence (LED) M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
MP Multiplicity M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
MP Contribution to xND M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Effect of MP Energy Scale • DE = +/- 25% D log x = +/- 0.1 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Answer to Q#2 Q : What is the effect of the MP energy scale calibration ? • A : An energy scale variation of +/- 25% yields • Dlog x = +/- 0.1. • Dlog x=0.1 is the bin width of our x distribution . • Peak position in data is centered where expected, indicating the energy scale uncertainty is < 25% . M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Question #3 Q : What is the background in the RP inclusive rate ? M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
RP Inclusive Data M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Zero Crossings M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003
Answer to Q#3 Q : What is the background in the RP inclusive rate ? A : It is 1-2% of all RP triggers, concentrated at log x < - 3 M. Gallinaro, `` RunII Diffractive Results: Blessing'' - QCD meeting, March 7, 2003