Diffraction at CDFand

Universality of Diffractive Factorization Breaking

Konstantin GoulianosThe Rockefeller University

http://physics.rockefeller.edu/dino/my.html/

Low x 2010, 23-27 June 2010 Kavala (Greece)

Phillippi Thassos

CONTENTS

Introduction

Diffraction at CDF: latest results

Dijets

W and Z

Jet-Gap-Jet

Universality of Diffractive Factorization Breaking

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 3 K. Goulianos

INTERACTIONSDiffractive:

Colorless exchange carrying vacuum quantum numbers

Non-diffractive:Color-exchange

POMERON

Goal: understand the QCD nature of the diffractive exchange

rapidity gapIncident hadrons acquire colorand break apart

CONFINEMENT

Incident hadrons retain their quantum numbersremaining colorless

pseudo-DECONFINEMENT

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 4 K. Goulianos

Definitions

s

Mξ-1

2

L x

22 M

1

dM

dσ

ξ

1

dξ

dσconstant

Δηd

dσ

0t

dN/d

M

pp’

p’rap-gap

=-ln0

p

M,t

p

p

p’ Lpξ

ln M2

ln s

particles

M2 scaling: no price paid for increasingdiffractive gap size

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 5 K. Goulianos

Diffractive pp(pp) processes @ CDF

Single Diffractiondissociation (SD)

Double Diffractiondissociation (DD)

Double PomeronExchange (DPE)

Central Diffraction

Single + DoubleDiffraction (SDD)

SD SD SD SDD

Elastic scattering Total cross sectionT=Im fel (t=0)

OPTICALTHEOREM

gap

nested gap

use gap nesting until no diffractive gap fits in √s'

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 6 K. Goulianos

M2 scaling

KG&JM, PRD 59 (1999) 114017

factorization breaks down to ensure M2 scaling - why?

12

2

2 )(M

s

dM

d

Regge

1

Independent of s over 6 orders of magnitude in M2 !

ddM2|t=-0.05 independent of s over 6 orders of magnitude!

data

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 7 K. Goulianos

TSD (pp & pp)

Factor of ~8 (~5)suppression at √s = 1800 (540) GeV

suppressed relative to Regge

KG, PLB 358, 379 (1995)

1800

GeV

540

GeV

M,t

p

p

p’

TSD mb

√s=22 GeV

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 8 K. Goulianos

REMARKS

MC generators for diffractive studies:

PYTHIA & PHOJET disagree with each other and with data. Diffractive factorization breaking at HERA:

Vector mesons: vs. W, b-slopes of t-distributions, …

Dijets: ETjet dependence, resolved vs. direct

components, . ..

Renormalization (RENORM) model: describes both p ( p ) - p and – p

MC based on RENORM model:

MBR (Minimum Bias Rockefeller) used at CDF.

Luminosity measurement: requires a known x-section and MC predicted acceptance of a detector component.

suggest SD: well defined and slowly varying x-section

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 9 K. Goulianos

The CDF II Detector

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 10 K. Goulianos

Diffractive Structure Function breakdown of QCD factorization !

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 11 K. Goulianos

Diffractive Structure Function

CDF

H1

momentum fraction of parton in “Pomeron” – note quotes

Using preliminary PDF’s from

same suppressionas in soft diffraction – why?

Xdijetppp

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 12 K. Goulianos

Dijet ET distributions

similar for SD and ND over 4 orders of magnitude Kinematics

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 13 K. Goulianos

DSF from Dijets in Run II

)(xF

)(xF

BjNDjj

BjSDjj

)(xRate

)(xRate)R(x

BjNDjj

BjSDjj

Bj

t - distribution

• The xBj-distribution of the SD/ND ratio has no strong Q2 dependence• the slope of the t-distribution is independent of Q2

• the t-distribution displays a diffraction minimum at |t| ~ 2.5 (GeV/c)2 (?) all three results “first observation”

?????? ??????

xBj - distribution

CDF Run II PreliminaryCDF Run II Preliminary

b - slope of t-distribution

?

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 14 K. Goulianos

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

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 15 K. Goulianos

Diffractive W / Z - analysis

CDF Run II Preliminary

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 16 K. Goulianos

Diffractive W / Z - results

CDF Run II Preliminary

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 17 K. Goulianos

CENTRAL GAPS

JetJet gap

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 18 K. Goulianos

DIFFRACTION PHENOMENOLOGY

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 19 K. Goulianos

Gap probability MUST be normalized to unity!

Single Diffraction

yy

yt ,2 independent variables:

t

colorfactor

17.0)0(

)(

ppIP

IPIPIP tg

yoyt

p eetFCyddt

d

222

)(

gap probability sub-energy x-section

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 20 K. Goulianos

Single diffraction (re)normalized

yoyt

pgap eetFCNyddt

d

222

)(

s

sCdtydtyPsN s

gaptygap ln),()(

2

,1

tybsy eseCyddt

d )2()ln(2

0ln

Pumplin bound obeyed at all impact parameters

Grows slower than s

),( tyPgap

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 21 K. Goulianos

Unitarity and Renormalization

Two free parameters: s0 and gPPP

Obtain product gPPP•s0 from SD

Renormalized Pomeron flux determines s0

Get unique solution for gPPP

Pomeron-proton x-section

)(sσξ)(t,fdtdξ

σdpIPIP/p

SD2

0s

)(s /20 tgPPP

Pomeron flux gap probabilitySet to unity – determines gPPP and s0

KG, PLB 358 (1995) 379

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 22 K. Goulianos

Dijets in p at HERA from RENORM

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 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 23 K. Goulianos

Multi-gap Diffraction

1y 2y1y 2y

1y 2y

(KG, hep-ph/0205141)

y

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 24 K. Goulianos

Multi-gap 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 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 25 K. Goulianos

Rapidity Gaps in Fireworks

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 26 K. Goulianos

“Gap survival probability”

0.23GeV)(1800S gapgap/01gapgap/12

0.29GeV)(630S gapgap/01gapgap/12

S =

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 27 K. Goulianos

Hard Diffraction Phenomenology

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 28 K. Goulianos

Diffractive dijets @ Tevatron

),/(1

),,( 22

21 QQ xFxF D

pjet

reorganizep

jet

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 29 K. Goulianos

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 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 30 K. Goulianos

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 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 31 K. Goulianos

Diffractive DIS @ HERA

),(1

),,( 221

2)3(2 QQ xFxF D

eQ2*

p

jet

reorganize

J. Collins: factorization holds (but under what conditions?)

e*

tp

IP

Pomeron exchange Color reorganization

Results favor color reorganization

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 32 K. Goulianos

Dijets in p at HERA - 2008

DIS 2008 talk by W. Slomiński,

ZEUS

20-50 % apparent rise when ETjet 510 GeV

due to suppression at low ETjet !!!

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 33 K. Goulianos

Vector meson production(Pierre Marage, HERA-LHC 2008)

left - why different vs. W slopes? more room for particles right - why smaller b-slope in *p? same reason

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 34 K. Goulianos

Unexpected, notunderstood

QCD factorisationnot OK

Dijets in p at HERA – 2007

Hadron-like

eQ2*

p

jet

reorganize

Direct vs. resolved

the reorganization diagram predicts:

suppression at low Z|Pjets, since larger is available for particles

same suppression for direct and resolved processes

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 35 K. Goulianos

Pomeron ' and t in a QCD inspiredparton model approach

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 36 K. Goulianos

SD and ratio of '

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 37 K. Goulianos

The total x-section

√sF=22 GeV

SUPERBALL MODEL

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 38 K. Goulianos

Monte Carlo Strategy for the LHC

T from SUPERBALL model optical theorem Im fel(t=0) dispersion relations Re fel(t=0) differential SD from RENORM use nested pp final states forpp collisions at the IP p sub-energy √s‘

See K. Goulianos, Phys. Lett. B 193 (1987) 151 pp“A new statistical description of hardonic and e+e− multiplicity distributions “

T

optical theoremIm fel(t=0)

dispersion relationsRe fel(t=0)

MONTE CARLO STRATEGY

CONCUSIONstay tuned …

low-x 27-29 June 2010 Kavala Diffraction at CDF and Universality of DFB 39 K. Goulianos

The first CMS event