Diffractive and Exclusive Production at CDF II

1
Diffractive and Exclusive Productionat CDF II
Konstantin Goulianos The Rockefeller
University - for the CDF Collaboration -
2
Contents

• Introduction
• Diffractive di-jets
• Diffractive W / Z
• Exclusive di-jets
• Exclusive di-leptons di-photons
• Exclusive Z
• Central Gaps in soft hard diffraction
• Summary

3
Overview
Soft and hard diffractive and exclusive studies
at CDF
DD
DPE
SDDSDDD
SD
exclusive
JJ, b, J/y, W
4
SD kinematics
x,t
dN/dh
rap-gap
Dh-lnx
h
0
5
Breakdown of factorization
Run I
e
g
p
soft
hard
p
p
p
Magnitude same suppression factor in soft and
hard diffraction! Shape of b distribution ZEUS,
H1, and Tevatron why different slapes?
6
M2 scaling? ds/dM2 independent of s !
Run I
KGJM, PRD 59 (1999) 114017
? Independent of s over 6 orders of magnitude in
M2 !
Factorization breaks down so as to ensure M2
scaling!
7
M2 scalingexpected in QCD
Run I
p
p
p
M
dN/dh
rapgap
Dh-lnx
h
0
ln M2
ln s
vacuum exchange
8
Hard diffractive fractions
Run I
Fraction SD/ND ratio _at_ 1800 GeV
Fraction
0.75 /- 0.10
JJ
0.115 /- 0.55
W
0.62 /- 0.25
b
1.45 /- 0.25
J/y
dN/dh

• All fractions 1
• (differences due to kinematics)
• uniform suppression
• FACTORIZATION !

FACTORIZATION !
h
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Multi-gap diffraction- restoring factorization -
Run I
w/preliminary pdfs from
The diffractive structure function measured on
the proton side in events with a leading
antiproton is NOT suppressed relative to
predictions based on DDIS
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Gap Survival Probability
Run I
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DIFFRACTIVE DIJETS
Systematic uncertainties due to energy scale and
resolution cancel out in the ratio
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Diffractive Structure FunctionXBj and Q2
dependence
ETjet 100 GeV !

• Small Q2 dependence in region 100 lt Q2 lt 10 000
  GeV2
• Pomeron evolves as the proton!

13
Diffractive Structure Functiont- dependence
Fit ds/dt to a double exponential

• Remaining work
• Obtain slope normalization
• Extend range to t 4 GeV2

• No diffraction dips
• No Q2 dependence in slope
• from inclusive to Q2104 GeV2

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Diffractive W/Z production

• Diffractive W production probes the quark content
  of the Pomeron
• To leading order,
  the W is produced
  by a
  quark in the
  Pomeron

• Production by gluons is suppressed by a
  factor of aS, and can be distinguished from quark
  production by an associated jet

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Diffractive W/Z - motivation

• In Run I, combining diffractive dijet production
  with diffractive W production was used to
  determine the quark/gluon content of the Pomeron
  ?
• In Run II, we aim at determining the diffractive
  structure function for a more direct comparison
  with HERA.
• To accomplish this we use
• New forward detectors
• New methodology
• More data

Phys Rev Lett 78, 2698 (1997) Fraction of W
events due to SD Rw1.150.51(stat)0.20(syst)
for xlt0.1 integrated over t
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Diffractive W/Z analysis

• Using RPS information
• No background from gaps due to multiplicity
  fluctuations
• No gap survival probability problem
• The RPS provides accurate event-by-event x
  measurement
• Determine the full kinematics of diffractive W
  production by
• obtaining hn using the equation
• where
• This allows determination of
• W mass
• xBj
• Diffractive structure function

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W/Z selection requirements
Standard W/Z selection
Diffractive W/Z selection

• RPS trigger counters - MIP
• RPS track - 0.03lt x lt0.10, tlt1
• W? 50 lt MW(xRPS,xcal) lt 120
• Z ? xcal lt 0.1

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Reconstructed Diffractive W-Mass
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Rejection of Multiple Interactions
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Diffractive W/Z results
RW (0.03 lt x lt 0.10, tlt1) 0.97 0.05(stat)
0.11(syst)
Run I RW 1.150.55 for xlt0.1? estimate
0.970.47 in 0.03 lt x lt 0.10 tlt1)
RZ (0.03 lt x lt 0.10, tlt1) 0.85 0.20(stat)
0.11(syst)
CDF/DØ Comparison Run I (x lt 0.1)
DØ Phys Lett B 574, 169 (2003) Rw5.10.51(stat)
0.20(syst) gap acceptance Agap(0.214)
uncorrected for Agap? RW0.890.19-0.17
RZ1.440.61-0.52
CDF PRL 78, 2698 (1997) Rw1.150.51(stat)0.20(s
yst)gap acceptance Agap0.81 uncorrected
for Agap ? Rw(0.930.44) (Agap calculated from
MC)
Stay connected for FDW/Z
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Exclusive Dijet and Higgs Production
Phys. Rev. D 77, 052004
ExHuME
DPEMC
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Underlying Event (UE)
Is it modeled correctly?
The data and POMWIGBackground distributions in
the transverse Df-region relative to the di-jet
axis agree, indicating that the UE is correctly
modeled.
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Inclusive DPE W/LRGp Data vs. MC
DPEMC
?exclusive MC models?
ExHuME
Rjj
DPEMC exclusive DPE MC based on Regge theory
ExHuME (KMR) gg?gg process (based on LO pQCD)
Shape of excess of events at high Rjj is well
described by both ExHuME DPEMC but
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ExHuME vs. DPEMC and vs. data

• Measured x-sections favor ExHuME

• KMR x 1/3 agrees with data
• ? Within theoretical uncertainty of /- factor of
  3

• sjjexcl/sincl approx. independent of ETmin

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Heavy Flavor suppression vs. Inclusive Signal
HF suppression
HF suppression vs. Incl
Invert HF vertically and compare with 1-MC/DATA ?
good agreement observed
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Exclusive Dijet x-section vs. Mjj

• line ExHuME hadron-level exclusive di-jet cross
  section vs. di-jet mass
• points derived from CDF excl. di-jet x-sections
  using ExHuME

Stat. and syst. errors are propagated from
measured cross section uncertainties using Mjj
distribution shapes of ExHuME generated data.
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Exclusive ll and gg
PRL under coll. review
PRL98, 112001 2007
PRL99, 242002 2007
PRL under coll. review
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Exclusive J/y and y(2s) production

• J/y production
• d?/dyy0 3.92 0.62 nb
• In agreement with av. Prediction of 3.0 0.3 nb
• 2.8 nb Szczurek07,, 2.7 nb
  KleinNystrand04,
• 3.0 nb ConclavesMachado05, and
• 3.4 nb MotkyaWatt08.
• Y(2s) production
• d?/dyy0 0.54 0.15 nb
• R ?(2s)/J/?? 0.14 0.05
• In agreement with HERA
• R 0.166 0.012 in a similar kinematic region

QED continuum
James Pinfold http//www.fp420.com/conference/de
c2008/index.html
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Exclusive cc?J/y(mm-) g production
Allow extra EM tower

• Allowing EM towers (with EmET gt 80 MeV gives a
  large increase in the J/y peak but a minor change
  in the y(2s) peak
• ? Evidence for cc ? J/y g production

ds/dyy0 75 14 nb, compatible with
theoretical predictions of 150 nb (Yuan 01) 130
nb (KRS01) error of O(50 nb)
James Pinfold http//www.fp420.com/conference/de
c2008/index.html
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Exclusive mm- and the Odderon

• The odderon would contribute to J/y, y(2s)
  (?) peaks -not the cc
• The J/? ?(2s) cross-sections agree with
  predictions (that fit the HERA data) ? no
  significant odderon signa
• R (exp./theory) J/? 1.32 0.41 , R
  (exp./theory)???s? 1.15 0.21
• R(data/theory) combined J/? ???s) 1.19
  0.19
• Limit on odderon prod. - R(O-IP)?V/(?-IP)?V
  lt 0.34 (95 CL)
• Another limit R(Og)IP?J/y / IP-IP? cc(3415)
  lt 0.060 0.015

James Pinfold http//www.fp420.com/conference/de
c2008/index.html
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Exclusive Upsilon photoproduction
CDF Run II Preliminary
Y(1S)
Y(2S)
Y(3S)
Y(3S)
M(mm-) with pT(mm-)lt 1.5 GeV/c and p-Df lt 0.34
rad
Michael Albrow http//www.fp420.com/conference/d
ec2008/index.html
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Exclusive Z / ?? ? ll studies
Exclusive Z SM cross section 0.3 fb
Motyka Watt1 1.3 fb Goncalves
Machado2 Expect 0.6 - 2.6 events in 2 fb-1
(not including 3.37 leptonic BF). ?Search for
BSM physics, e.g. color sextet quark model3
much enhanced cross section expected.
ee or mm

• 1 Phys. Rev. D78, 014023 (2008)
• 2 Eur. Phys. J., C56 33 (2008)
• 3 Phys. Rev. D72,036007

• Exclusive di-lepton cross section
• Background to exclusive Z
• Can be used to calibrate forward proton
  detectors
• ? s-1/2 ?pTle-?l

ee or mm
Emily Nurse http//www.fp420.com/conference/dec2
008/index.html
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Exclusive z / ?? ? ll results
L 2.20 (2.03) fb-1 in the electron (muon)
channels
ee- or ??- with pT gt 25 GeV ??1 lt 1.0, ??2
lt 1.5 ?e1 lt 1.3, ?e2 lt 3.6 require 82 lt Mll lt
98 GeV
W?l? events used as a control to study
exclusivity cuts
CDF Run II Preliminary
Exclusive Z ?(Zexcl)lt 0.96 pb _at_ 95 C.L. SM
0.3 fb Motyka Watt 1.3 fb
Goncalves Machado
Exclusive di-leptons ? (pp?p l l p) 0.24
pb Mll gt 40 GeV, ?l lt 4.0 LPAIR
prediction ? 0.256 pb
0.13 - 0.10
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CENTRAL RAPIDITY GAPS
jet

• Measure DYgap width and position
• to differentiate among models.

Christina Mesropian http//www.cs.infn.it/diff20
08/program.html
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Low Luminosity Run
? January 2006 data with dedicated diffractive
triggers ?
Low Lum 0.5E30
2002-303 data 1.5E31
single diffraction 0.03 lt x lt 0.1
diffractive dijet overlapped with MB soft
diffraction
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MiniPlug Jets
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MiniPlug Jet Properties
ETjet1,2 gt 2 GeV, 3.5 lthjet1,2lt 5.1,
hjet1.hjet2 lt0
E
ET
h?
f ?
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MP Jet Data with TOF Veto
Data with TOF veto
The number of CCAL towers with ETgt200 MeV is
suppressed by the TOF veto
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CCAL gap
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CCAL PCAL p/pbar Gap
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CCAL PCALp PCALpbar Gap
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Gap fraction in CCAL gap Events
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SUMMARY

• Introduction
• Renormalization, M2-scaling, survival
  probability
• Diffractive and non-diff. proton PDFs similar
• Diffractive dijets xBj, Q2 and t-dependece
• Diffractive W/Z with RPS data
• W diffractive fraction in agreement with Run I
• W and Z diffractive fractions are equal within
  error
• Exclusive dijets and exclusive Higgs _at_ LHC
• Exclusive di-lepton and di-photon measurements
• Exclusive Z production limit
• Central rapidity gaps
• Gap fraction dependence on width and h-position
  of gap for hard / soft triggers at hgt4
• distributions shapes similar for hard / soft
  triggers
• ? hard-scale fractions suppressed by factor of or
  10.

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thank you
thank you
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BACKUP
Measurements w/ the MiniPlugs
Dynamic Alignment of RPS Detectors
ETjet Calibration
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Measurements w/the MiniPlugs
MULTIPLICITY _at_ POSITION
ENERGY

• ADC counts in MiniPlug towers
• in a pbar-p event at 1960 GeV.
• jet indicates an energy cluster
• and may be just a hadron.
• 1000 counts 1 GeV

NIM A 430 (1999) NIM A 496 (2003) NIM A 518 (2004)
Multiplicity of SD and ND events
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Dynamic Alignment of RPS Detectors
Method iteratively adjust the RPS X and Y
offsets from the nominal beam axis until a
maximum in the b-slope is obtained _at_ t0.
Limiting factors 1-statistics 2-beam size 3-beam
jitter
_at_ CDF W/lowlum data
30 m achieved at CDF in the low luminosity run
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ETjet Calibration
?use RPS information to check jet energy
corrections?
Calibrate Etjet or x, as you wish!
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Poster