CDF RESULTS ON DIFFRACTION and EXCLUSIVE PRODUCTION
Konstantin Goulianos
14th Workshop on Elastic and Diffractive Scattering (EDS Blois Workshop)
Frontiers of QCD: From Puzzles to DiscoveriesDecember 15-21, 2011, Qui Nhon, Vietnam
EDS 2011 Vietnam Diffractive & exclusive production in CDF
CONTENTS Diffractive W and Z production……………………..published Diffractive structure function in dijet production ..…updated Rapidity gaps between jets………….......................updated
__________________________________________________ Diffr. structure function at low x using rap-gaps .….difficult ! Diffr. structure function in DPE dijet production…. ..delayed
__________________________________________________ Exclusive gg production in pp collisions at 1.96 TeV….NEW!
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
In LO QCD W probes the quark content of diffractive exchange.
Production by gluons is suppressed by a factor of aS and distinguished by an associated jet.
Diffractive W/Z
MW
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
MW from inclusive We/m+vMethod: compare transverse MW data with MC
MWdiff= 80.9± 0.7(GeV/c2)
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
Diffractive W/Z fractions
~80% 68-80% ~87% f1-int =(25.6±1.2)%
RW (0.03 < x < 0.10, |t|<1)= [1.00 ± 0.05(stat.) ± 0.10(syst.)]%
Run I: RW =1.15±0.55 % for xmin<x<0.1 [0.97±0.47 (stat. & syst.) % within 0.03 < x < 0.10 & |t|<1
RZ (0.03 < x < 0.10, |t|<1)= [0.88 ± 0.21(stat.) ± 0.08(syst.)]%
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EDS 2011 Vietnam
Diffractive Structure Function in Dijets
)(xF)(xF
BjNDjj
BjSDjj
)(xRate)(xRate
)R(xBj
NDjj
BjSDjj
Bj Þº
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DSF: Q2 - dependence
ETjet ~ 100 GeV !
Small Q2 dependence in region 100<Q2<10 000 GeV2
where dsSD/dET & dsND/dET vary by a factor of ~104 !
The Pomeron evolves as the proton !EDS 2011 Vietnam Diffractive & exclusive production in CDF 7
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
Dijet ET distributions
similar for SD and ND over 4 orders of magnitude Kinematics
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
t – dependence: |t|<1 (GeV/c)^2
No diffraction dips No Q2 dependence up to to Q2~104 GeV2
Fit ds/dt to a double exponential: Same slope over entire region ~1 < Q2 < ~ 10 000 GeV2!
0.05 < x < 0.08b1
b2
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
|t| up to 4 (GeV/c)2
diffractive dip region?
must reevaluate errors!10
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
Asymmetric t distributions: A tool for evaluating background level!
• • 2 mm
2.5 mmpp7.5 mm
12.5 mm
x
Y
25 mm
tracker’s upper edge: |t|=2.3 (GeV/c)^2, estimated from t~q^2 the lower edge is at |t|= 6.5 (GeV/c)^2 (not shown) background level: region of Ytrack>Yo data for |t|>2.3 (GeV/c)^2
bgd =2 evts/(GeV/c)2
schematic view of fiber tracker t-distributions
Y = 7.5 mm
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EDS 2011 Vietnam Diffractive & exclusive production in CDF
RPS acceptance vs. t and x
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gaps between jets
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