konstantin goulianos the rockefeller university diffraction at cdf and at the lhc low x meeting:...
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Konstantin GoulianosThe Rockefeller University
Diffraction at CDF and at the LHC
LOW X MEETING:
HOTEL VILLA SORRISO, ISCHIA ISLAND, ITALY, September 8-13 2009
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 2
theme: factorization breaking in diffraction pp and pp results p and *p results renormalization: the common thread diffraction at the LHC
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 3
pp and pp results
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 4
pp results from CDF
JJ, b, J/W ppJJ…ee… exclusive
soft and hard diffractive processes studied at CDF
Single Diffractiondissociation (SD)
Double Diffractiondissociation (DD)
Double PomeronExchange (DPE)
Single + DoubleDiffraction (SDD)
http://physics.rockefeller.edu/publications.html#diffractionsee also CDF talks in this conference by M. Albrow and J. Pinfold
SD SD SD SDD
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 5
TSD (pp & pp)
Factor of ~8 (~5)suppression at √s = 1800 (540) GeV
suppressed relative to Regge prediction
KG, PLB 358, 379 (1995)
1800
GeV
540
GeV
M,t
p
p
p’
TSD mb
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 6
M2 scaling d/dM2 independent of s over 6 orders of magnitude!
KG&JM, PRD 59 (1999) 114017
factorization breaks down to ensure M2 scaling!
12
2
2 )(M
s
dM
d
renormalization
1
Independent of s over 6 orders of magnitude in M2 !
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 7
Gap survival probability - S
0.23GeV)(1800S gapgap/01gapgap/12
0.29GeV)(630S gapgap/01gapgap/12
S =
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 8
TSD and dijets
~8
ZEUS and H1 vs. CDF
ξ
xβ H1
ZEUS
CDFKG, PLB 358 (1995) 379
1dtdξξ)(t,f0.1
ξ
IP/p
0
tmin
Tsd
~ 8
soft*e
pp p
pp
dijet
Magnitude: same suppression factor in soft and hard diffraction!Shape of distribution: ZEUS, H1, and Tevatron – why different slapes?
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 9
Dijets - ET distributions
similar for SD and ND over 4 orders of magnitude Kinematics
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 10
Dijets: diffractive structure functionxBj and Q2 dependence
ETjet ~ 100 GeV !
Small Q2 dependence in region 100 < Q2 < 10,000 GeV2
Pomeron evolves as the proton!
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 11
Dijets - diffractive structure functiont- dependence
No Q2 dependence in slope from inclusive to Q2~104 GeV2
Fit d/dt to a double exponential
Same slope over entire region of ~1< Q2 < 4,500 GeV2
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 12
All fractions ~ 1% (differences due to
kinematics) ~ uniform suppression
~ FACTORIZATION !
Hard diffractive fractions
dN/d
gap)( Xpp
1.45 +/- 0.25J/
0.62 +/- 0.25 b
0.115 +/- 0.55W
0.75 +/- 0.10JJ
Fraction (%)Fraction: SD/ND @ 1800 GeV
FACTORIZATION !
Run I
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 13
Diffractive W/Z production - Run II
W, Z
p
p
pIP
Diffractive W production probes the quark content of the Pomeron
Production by gluons is suppressed by a factor of S
W, Z
p
p
p
IP
RW (0.03 < < 0.10, |t|<1)= [0.97 ± 0.05(stat) ± 0.11(syst)]%
Run I: RW =1.15±0.55 % for <0.1 estimate 0.97±0.47 % in 0.03 < < 0.10 & |t|<1)
RZ (0.03 < x < 0.10, |t|<1)= [0.85 ± 0.20(stat) ± 0.11(syst)]%
Fractions RW and RZ are equal within uncertainties
DIFFRACTIVE FRACTIONS
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 14
Multi-gap dijets - 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
R(SD/ND)
R(DPE/SD)DSF from ratio of two/one gap:factorization restored!
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 15
Exclusive dijet and Higgs production
HDPEMC
Phys. Rev. D 77, 052004
ExHuME
suppression factor ~ 50
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 16
Central gaps
JetJet gap
inclusive
dijets
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 17
p and *p results
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 18
Vector meson production(Pierre Marage, HERA-LHC 2008)
left - why different vs. W slopes? right - why smaller b-slope in *p?!
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 19
Unexpected, notunderstood
Hadron-like
QCD factorisationnot OK
Dijets in p at HERA - 2007[slide from summary of the HERA/LHC Workshop of March 14, 2007]
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 20
Dijets in p at HERA - 2008
DIS 2008 talk by W. Slomiński,
ZEUS
20-50 % rise (?) from ET 510 GeV
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 21
Renormalization: the common thread works for pp, pp, p and *p
figure from http://en.wikipedia.org/wiki/Thread_(computer_science)
removes overlapping gaps!
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 22
SD: M2 scalingis expected in QCD
s
Mξ-1
2
L x
22 M
1
dM
dσ
ξ
1
dξ
dσconstant
Δηd
dσ
0t
dN/d
M
pp’
p’rapgap
=-ln0
p
M,t
p
p
p’ Lpξ
ln M2
ln s
vacuumexchange
particles
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 23
Multigap cross sections
ssty ln/2~,
Same suppressionas for single gap!
2122
2-1i1
2
51
5
)( yyo
ytp
ii
eetFCdV
dii
Gap probability Sub-energy cross section(for regions with particles)
1y 2y1y 2y
1y 2y
1t 21 yyy 5 independent variables2t color
factor
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 24
Diffractive dijets @ Tevatron
),/(1
),,( 22
21 QQ xFxF D
pjet
reorganizep
jet
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 25
FDJJ(,Q2) @ Tevatron
2
sβ
ξ
dξN
ε
ε
2sβ
1
β
xξ1
ξ 211
renorm
minmin
min
)2(
)(1
12
2R
2RENORM
xQs
xSDND
4.02.0 xg
)()(renorm
22
2
2
2 )(12
)/(
)(1N),,( 21221 Q
Q
Q
C
sx
CF D
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 26
SD/ND dijet ratio vs. xBj@ CDF
(x)F
(x)FR(x) ND
jj
SDjj
0.035 < < 0.095
Flat dependencefor < 0.5
CDF Run I
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 27
Diffractive DIS @ HERA
),(1
),,( 221
2)3(2 QQ xFxF D
eQ2*
p
jet
reorganize
J. Collins: factorization holds (but under what contitions?)
e*
tp
IP
Pomeron exchange Color reorganization
CQ
CF
Q
QQD
21212)3(
2 )(1
)()(
)(1),,(
2
Contradicted bydirect vs. resolved DIS
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 28
Inclusive vs. diffractive DISKG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092
F2 ~ x
q
(q)/2
)()(1
)()(
)(1),,( 22121
2)3(2
2
Q
CQ
CF
Q
QQD
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 29
Dijets in p at HERA: the expectation
Factor of ~3 suppressionexpected at W~200 GeV(just as in pp collisions)
for both direct and resolved components
K. Goulianos, POS (DIFF2006) 055 (p. 8)
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 30
Unexpected, notunderstood
Hadron-like
QCD factorisationnot OK
Dijets in p at HERA - 2007
see figure on right: same suppression for direct and resolved processes suppression at low zjets since larger available for particles
eQ2*
p
jet
reorganize
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 31
Vector meson production(Pierre Marage, HERA-LHC 2008)
left - suppression of 20-50% at high W more room for particles right - suppression at low |t| for high Q2 same reason
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 32
Diffraction at the LHC
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 33
FROM EDS 2009, 39 Jun 2009, CERN --Discussion panel
"What can we learn/expect from the LHC experiments?“ K. Goulianos
goal…….......understand the QCD basis of diffraction & discover new physics
TEV2LHC…confirm, extend, discover…
Tools……….larger √s larger , & ET
TODO:
Elastic, diffractive, and total cross sections
Important to study partial cross section components
need topology (multiplicity, ET, …)
Hard diffraction
diffractive structure function dijets vs. W
Multigap configurations
jet-gap-jet d/d vs. ETjet BFKL, Mueller-Navelet
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 34
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?
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 35
SUMMARY Diffraction results from CDF were presented under the physics theme of factorization breaking in diffraction. Results from p (*p) interactions at HERA were also discussed focusing on factorization breaking aspects. Renormalization of the rapidity gap probability was
proposed as the common thread in explaining factorization breaking by eliminating double-counting from overlapping rapidity gaps. Suggestions for diffractive studies at the LHC were offered, thank youfor your
attendance
LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 37
The CDF II detectors
RPS acceptance ~80% for 0.03 < < 0.1 and |t| < 0.1