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

QQ

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 36

BACKUP

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

LOW X 2009, Ischia, September 8-13 Diffraction at CDF and at the LHC K. Goulianos 38

ξ

1

β

1~ξβ,FD

jj Pomeron dominated

constantdξ

dσincl

0.10.90.11.0

Djj ξ

1

β

1ξβ,F

& dependence of FDjj – Run I