Blessing of run ii diffractive results
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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 of Run II Diffractive Results

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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 events352,359

  • MET Significance<6352,359

  • 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 E312.3 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


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