K. Goulianos The Rockefeller University Diffractive and Total Cross Sections @ Tevatron and LHC HCP 2006 Duke University, NC, USA, 22-26 May 2006 CDF.
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K. Goulianos
The Rockefeller University
Diffractive and Total Cross Sections
@ Tevatron and LHC
HCP 2006Duke University, NC, USA, 22-26 May 2006
CDF results are presented on behalf of the CDF Collaboration
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 2
Contents
Introduction Total Cross Sections Diffraction Exclusive Production
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 3
p-p InteractionsDiffractive:
Colorless exchange with vacuum quantum numbers
Non-diffractive:Color-exchange
Incident hadrons retain their quantum numbersremaining colorless
pseudo-DECONFINEMENT
Incident hadrons acquire colorand break apart
CONFINEMENT
POMERON
Goal: understand the QCD nature of the diffractive exchange
rapidity gap
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 4
Elastic Scattering
dt
d
2
π
)(p4
R
c
GeV13b
m
1R
e~bte~dt
dσ 22
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 5
Diffraction Dissociation
S
M
P
P X
L
L2
ξ
025.02
2
tdMdt
d
Momentum loss fraction
COHERENCE CONDITION
1.0m
m
p
< 0.1
d
?M
1~
dM
dσwhyBut
22
@Tevatron MX 600 GeV@ LHC 4.4 TeV
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 6
Rapidity Gaps
ξ
1~
dξ
dσ
M
1~
dM
dσconstant
Δηd
dσ22
0t
p pX p
p
Particle production Rapidity gap
-ln ln MX2
ln s
X
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 7
Diffractive pp Processes
Elastic scattering Total cross section
SD DD DPE SDD=SD+DD
T=Im fel (t=0)
OPTICALTHEOREM
GAP
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 8
Rapidity Gaps in Fireworks
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 9
The Physics Elastic and Total Cross Sections:……….pppp and ppX
Fundamental Quantum Mechanics Froissart Unitarity Bound……….T < C ln2s Optical theorem………………………..T ~Im f(t=0) Dispersion relations………………....Re f(t=0)~Im f(t=0) Is space-time discrete? Measure the -value at the LHC!
Diffraction Dissociation:………………pppX, pppXp, ppXGX, pppXGX Non-perturbative QCD
Soft & hard diffraction Factorization Multi-gap diffraction Diffraction in QCD:…….……what is the Pomeron? Dark energy?
Exclusive Production:………………….…..pppp+A (jet+jet, , …, H0) Discovery channel
Diffractive Higgs production at the LHC (?)
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 10
Tevatron Experiments
InfoExp
RomanPots
El TSoft diffraction
Hard diffraction
E710/811(Scint. Counters)
p, pbar
x x sd
CDF-0p, pbar
x x sd
CDF-I pbarsd,dd,dpe,sdd
JJ,b,J/,W,JGJ
CDF-II pbar sd JJ,W,Z,JGJExclusive JJ,
D0-I JJ,W,Z,JGJ, …
D0-IIp, pbar
x x sd,dpe,…JJ,W,Z,JGJ,…Exclusive ???
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 11
CDF Run 1-0 (1988-89)Elastic, diffractive, and total cross section @ 546 and 1800 GeV
Roman Pot Spectrometers
Roman Pot Detectors Scintillation trigger counters Wire chamber Double-sided silicon strip detector
Roman Pots with Trackers up to || = 7
CDF-I
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 12
CDF-IRun-IC Run-IA,B
Forward DetectorsBBC 3.2<<5.9 FCAL 2.4<<4.2
beam
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 13
CDF-II ROMAN POT DETECTORS
BEAM SHOWER COUNTERS:Used to reject ND events
MINIPLUG CALORIMETER
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 14
CDF & D0 - Run II
Z(m)
D SQ2Q3Q4S A1A2
P1U
P2I
P2O
P1DD2 D1
233359 3323057
Q4Q3Q2
From Barreto’s talk in small-x
D0
LM 2.5<η<4.4VC 5.2<η<5.9
Z(m)
p
D Q2Q3Q4
p
RP3 RP1
2332 3223057
Q4Q3Q2
MP 3.5<η<5.5 BSC1 5.5<η<7.5
RP2
S S
BSC4 BSC2BSC3 BSC2 BSC3CDF
CDF & D0:COMPLIMENTARY
COVERAGE
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 15
ELASTIC AND TOTAL CROSS SECTIONS
At Tevatron:CDF and E710/811
use luminosity independent methodOptical theorem
Alert: background Ninel yields small T
undetected Ninel yields large T
inelelt
elT
inelelTt
elT
NNdt
dN
NNLdt
dN
L
1
1
16
1~&
1
11~
02
02
2
optical theorem
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 16
T and -values from PDG
E710
= ratio of real/imaginary partsof elastic scattering amplitude at t=0
E811
CDFCDF and E710/811 disagree
CDF & UA4
T
optical theoremIm fel(t=0)
dispersion relationsRe fel(t=0)
E811
N. Khuri and A. Martin: measuring at the LHC
tests discreteness of space-time
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 17
Total Cross Sections: Regge fitCMG: Covolan, Montagna, and G
PLB 389 (1995) 176
Simultaneous Regge fit to pp, p, and Kp x-sections using the eikonal approach to ensure unitarity
S
= 1.104 +/- 0.002
LHC = 115
mb @14 TeV
Bornlevel
DL
E710CDF
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 18
Elastic/Total and -values: Regge fitCovolan, Montagna, and G
PLB 389 (1995) 176
Agreement with data on:
b-slopesel/T
-values
Unitarity assured
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 19
Other Approaches
T (LHC) = 107.3 ± 1.2 mb
eg, M. Block, arXiv:hep-ph/0601210 (2006)
fit data using analyticity constraintsM. Block and F. Halzen, Phys. Rev. D 72, 036006
Recall CMG Regge fit: 115 mb
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 20
TOTEM experiment @ LHC
Total Cross Section, Elastic Scattering, and Diffraction Dissociation
Aim at 1% accuracy on T
RP stations
RP stations
CMS
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 21
DIFFRACTION Soft & hard diffraction
Factorization / renormalization
Multi-gap diffraction
Diffraction in QCD
Dark energy ???
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 22
Regge theory SD exceeds T at
Renormalization Pomeron flux integral (re)normalized to unity
A unitarity issue )(Mσξ)(t,f
dtdξ
σd 2XpIPIP/p
SD2
KG, PLB 358 (1995) 379
TeV.2s
1dtdξξ)(t,f0.1
ξ
IP/p
0
tmin
2~ sSD
Pomeron flux
Factorization
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 23
A Scaling Law in Diffraction
KG&JM, PRD 59 (1999) 114017
Factorization breaks down so as to ensure M2-scaling!
12
2
2 )(M
s
dM
d
renormalization
1
Independent of S over 6 orders of magnitude in M2 !
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 24
The QCD Connection
ytel etsf ),(Im
y sy ln
The exponential rise of T(y’) is dueto the increase of wee partons with y’
(E. Levin, An Introduction to Pomerons,Preprint DESY 98-120)
ses oy
oT )(y
sy lnTotal cross section:power law increase versus s
Elastic cross section:forward scattering amplitude
s
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 25
yy
yt ,2 independent variables:
yoyt
p eetFCyddt
d
222
)(
Gap probability
Renormalization removes the s-dependence SCALING
Single Diffraction in QCD
ye 2~ 22ln
minsyssy
y
t
colorfactor
(KG, hep-ph/0205141)
ε12
2ε
REGGE2 )(M
s
dM
dσ
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 26
Multi-gap Renormalization
ye 2~ 22ln
minsyssy
y
Same suppressionas for single gap!
1y 2y1y 2y
1y 2y
1t 21 yyy 5 independent variables
2t
2122
2-1i1
2
51
5
)( yyo
ytp
ii
eetFCdV
dii
Gap probability Sub-energy cross section(for regions with particles)
colorfactors
(KG, hep-ph/0205141)
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 27
Double Diffraction Dissociation
One central gap
Double Pomeron Exchange
Two forward gaps
SDD: Single+Double Diffraction One forward + one central gap
Central and Double Gaps @ CDF
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 28
One-gap cross sections are suppressed Two-gap/one-gap ratios are 17.0
Central & Double-Gap CDF Results
Differential shapes agree with Regge predictions
DD SDD DPE
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 29
Dark Energy
P(y) is exponentially suppressed
dy
dNρ,ey)P( particlesΔyρ
Rapidity gaps are formed bymultiplicity fluctuations:
Non-diffractive interactions
Δy2εe~0ty)P(
2lnlnln Msy
Rapidity gaps at t=0 grow with y:
Diffractive interactions
2: negative particle density!
Gravitational repulsion?
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 30
HARD DIFFRACTION Diffractive fractions
Diffractive structure function
factorization breakdown
Restoring factorization
Hard diffraction in QCD
dN/d
JJ, W, b, J/
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 31
All ratios ~ 1% ~ uniform suppression
~ FACTORIZATION !
Diffractive Fractions @ CDF
gap)( Xpp
1.45 (0.25)J/
0.62 (0.25)b
0.75 (0.10)JJ
1.15 (0.55)W
Fraction(%)Fraction:SD/ND ratioat 1800 GeV
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 32
The diffractive structure function at the Tevatron is suppressed by a factor of ~10 relative to expectation from pdf’s measured by H1 at HERA
Similar suppression factor
as in soft diffraction relative to Regge expectations!
Diffractive Structure Function:Breakdown of QCD Factorization
CDF
H1
= momentum fraction of parton in Pomeron
Using preliminary pdf’s from
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 33
Restoring QCD Factorization
R(SD/ND)
R(DPE/SD)DSF from two/one gap:factorization restored!
The diffractive structure function measured on the proton side in events with a leading antiproton is NOT suppressed relative to predictions
based on DDIS
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 34
Diffractive Structure Function:Q2 dependence
ETjet ~ 100 GeV !
Small Q2 dependence in region 100 < Q2 < 10,000 GeV2
Pomeron evolves as the proton!
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 35
Diffractive Structure Function:t- dependence
No diffraction dips No Q2 dependence in slope from inclusive to Q2~104 GeV2
Fit d/dt to a double exponential:
Same slope over entire region of 0 < Q2 < 4,500 GeV2
across soft and hard diffraction!
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 36
valence quarks
antiproton
x=
Hard Diffraction in QCD
proton
deep sea
Derive diffractivefrom inclusive PDFsand color factors
antiproton
valence quarks
p
p
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 37
EXCLUSIVE PRODUCTION
H
Measure exclusive jj & Calibrate predictions for H production rates @ LHC
Bialas, Landshoff,Phys.Lett. B 256,540 (1991)Khoze, Martin, Ryskin,Eur. Phys. J. C23, 311 (2002); C25,391 (2002);C26,229 (2002)C. Royon, hep-ph/0308283B. Cox, A. Pilkington,PRD 72, 094024 (2005)OTHER…………………………
Search for exclusive dijets:Measure dijet mass fraction
Look for signal as Mjj 1
rscalorimeteallM
MR
X
jjjj
Search for exclusive
Search for events with two high ET gammas and no other activity in the calorimeters or BSCs
KMR: H(LHC) ~ 3 fbS/B ~ 1 if M ~ 1 GeVClean discovery channel
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 38
Exclusive Dijet and Search b-taqged dijet fraction Dijet fraction – all jets
Exlusive b-jets are suppressedby JZ= 0 selection rule
Excess over MC predictions at large dijet mass fraction
Systematic uncertainties under study: tune in this summer for results
Exclusive Based on 3 events observed:
Good agreement with KMR:
pb0.03(syst)(stat)0.14σ 0.140.04MEAS
pb3)20.04(0.04σKMR
DIJETS
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 39
Looking forward @ LHC
TOTEM/CMS ATLAS
FP420 projectMeasure protons at 420 m from the IP during normal high luminosity running to be used in conjunction with CMS and ATLASFeasibility study and R&D for Roman Pot detector development Physics aim :pp p+ X + p (Higgs, New physics, QCD studies) Status: Project funded by the UK
HCP 2006, Duke U, May 22-26 Diffractive ant Total Cross Sections @ Tevatron and LHC K. Goulianos 40
Summary
TEVATRON – what we have learnt M2 – scaling Non-suppressed double-gap to single-gap ratios Pomeron: composite object made up from underlying pdf’s subject to color constraints
LHC - what to do Elastic and total cross sections & -value High mass 4 TeV and multi-gap diffraction Exclusive production (FP420 project) Reduced bgnd for std Higgs to study properties Discovery channel for certain Higgs scenarios
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