Aspen 13-20 Feb 2005Diffraction @ Tevatron / LHC K. Goulianos1 DIFFRACTION FROM THE TEVATRON TO LHC...

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Aspen 13-20 Feb 2005 Diffraction @ Tevatron / LHC K. Goulianos 1

DIFFRACTIONFROM THE TEVATRON TO LHC

Aspen Winter Conference13-20 February 2005

Konstantin Goulianos

The Rockefeller University


Forty Years of Diffraction

1960’s BNL: first observation of pp -> pX

1970’s Fermilab fixed target, ISR, SPS Regge theory & factorization

Review: KG, Phys. Rep. 101 (1983) 169

1980’s UA8: diffractive dijets hard diffraction

1990’s Tev Run-I: Regge factorization breakdownTev/ HERA: QCD factorization breakdown

21st C Multigap diffraction: restoration of factorizationIdeal for diffractive studies @ LHC

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


What is Dark Energy??

* * ** * *

H He

E

M

* * ** * *

H He

E

M


Diffraction Dissociation Diffraction Dissociation

KG, Phys. Rep. 101 (1983) 171

XLL/PΔPξ

1

~d

d

constant~yd

dσ

M

1~

dM

dσ22

s

M

p

Δpξ

2

L

L y

y

2ln M

slnln

y025.0dMdt

σd2

2

t

POMERON: color singlet w/vacuum quantum numbers


Rapidity Gaps

Gaps are exponentially suppressed

From Poisson statistics:

dy

dneyP y )(

(=particle density in rapidity space)

Rapidity gaps are formed bymultiplicity fluctuations.

Non-diffractive interactions

Bj, PRD 47 (1993) 101: regions of (pseudo)rapidity devoid of particles

ε122

0t M

1~

dM

dσΔy2εe~Δyd

dσ

2lnlnln Msy

Rapidity gaps at t=0 grow with y.Diffractive interactions

pp /

2: negative particle density!


Diffraction @ CDF in Run I

93(2004)141601


valence quarks

antiproton

x=

Diffraction in QCD

proton

)or(1

)( xxfx

g=0.20

q=0. 04

R=-0.5

g=0.5

q=0.3

SOFT HARD

deep sea

Derive diffractivefrom inclusive PDFsand color factors

antiproton

valence quarks

pp


CDF in Run I-0 (1988-89)Elastic, single diffractive, and total cross sections @ 546 and 1800 GeV

Roman Pot Spectrometers

Roman Pot Detectors Scintillation trigger counters Wire chamber Double-sided silicon strip detector

Results Total cross section tot ~ s Elastic cross section d/dt ~ exp[2’ lns] shrinking forward peak Single diffraction Breakdown of Regge factorization

Additional DetectorsTrackers up to || = 7


Regge Theory


Unitarity problem: With factorization and std pomeron flux SD exceeds T at

Renormalization: normalize the pomeron flux to unity

Renormalization )(Mσξ)(t,f

dtdξ

σd 2XpIPIP/p

SD2

KG, PLB 358 (1995) 379

TeV.2s

1dtdξξ)(t,f0.1

ξ

IP/p

0

tmin

~10

2~ sSD


A Scaling Law in Diffraction

KG&JM, PRD 59 (1999) 114017

Factorization breaksdown in favor of

M2-scaling

12

2

2 )(M

s

dM

d

renormalization

1


The QCD Connection

ytel etsf ),(Im

y sy ln

The exponential rise of T(y’) is dueto the increase of wee partons with y’

(see E. Levin, An Introduction to Pomerons,Preprint DESY 98-120)

yooT ess )(

y sy ln

Total cross section:power law rise with energy

Elastic cross sectionforward scattering amplitude

s


yy

yt ,2 independent variables:

yo

ytp eetFC

yddt

d

222

)(

Gap probability

Renormalization removes the s-dependence SCALING

QCD Basis of Renormalization

ye 2~ 22ln

minsyssy

y

t

colorfactor

17.0)0(

)(

ppIP

IPIPIP tg

(KG, hep-ph/0205141)


The Factors and

Experimentally: KG&JM, PRD 59 (114017) 1999

g=0.20

q=0.04

R=-0.5

fg=gluon fractionfq=quark fraction

λx

1f(x)x

18.03

125.0

8

175.0

121f

1

1f

2

Q

NN cq

cgColor factor:

12.0ww qqgg Pomeron intercept:

104.0,02.017.0

pIP

IPIPIPg

λ

/sxs~dxxf

1

1)(

CTEQ5L


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


2122

2-1i1

2

51

5

)( yyo

ytp

ii

eetFCdV

dii

Gap probability Sub-energy cross section(for regions with particles)

Multigap Renormalization

ye 2~ 22ln

minsyssy

y

Same suppressionas for single gap!

1y 2y1y 2y

1y 2y

1t 21 yyy 5 independent variables

2t colorfactors

(KG, hep-ph/0205141)


One-gap cross sections are suppressed Two-gap/one-gap ratios are 17.0

Central & Double-Gap ResultsDifferential shapes agree with Regge predictions

DD SDD DPE


Diffractive DIS @ HERA

),(1

),,( 221

2)3(2 QQ xFxF D

eQ2*

p

jet

reorganize

J. Collins: Factorization should hold

e*

tp

IP

Pomeron exchange Color reorganization


Inclusive vs Diffractive DIS

CCF

Q

QQD

1212)3(

2

1

)()(

)(1),,(

2

P(0)-1(q)/2

F2 ~ x

q

KG, “Diffraction: a New Approach,” J.Phys.G26:716-720,2000 e-Print Archive: hep-ph/0001092


diff/incl DIS at HERA

At fixed x:flat Q2-dependence

At fixed Q2:flat x-dependence


CDF-ICRun-IC Run-IA,B

Forward DetectorsBBC 3.2<<5.9FCAL 2.4<<4.2


All fractions ~ 1% Factorization ~ OK @ Tevatron

at fixed c.m.s. energy.

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(%)X

SD/ND fraction at 1800 GeV


Diffractive Dijets @ Tevatron

),/(1

),,( 22

21 QQ xFxF D

pjet

reorganizep

jet


Diffractive Structure F‘n @CDF XJetJetppp

SD/ND Rates vs • Measure ratio of SD/ND dijet rates as a f’n of

• In LO-QCD ratio of rates equals ratio of structure

fn’s

px

45.0p0p

ND

SD xR)(xR

px

s

eE/ppx

2(3)

1i

iηiT

pqg,p

))(xq)(x(q

C

C)g(xx)(xF pipi

A

Fpppjj


FDJJ(,Q2) @ Tevatron

C

sx

CF

Q

QQD

2122111

)/(

)(1),,(

)(

22

2

εε

2sβ

1~

β

xξ1

ξ 211

renorm sβξ

dξN

minmin

min

)2(

)(1

121

~R2

RENORM

x

QsxSD

ND

4.02.0 xg


Tevatron vs HERA:Factorization Breakdown

dN/dgap dN/dgap

p

ppIP

CDF

H1

p

ppIP

e*

tp

IP

Predicted in KG, PLB 358 (1995) 379


Restoring Factorization

R(SD/ND)

R(DPE/SD)DSF from two/one gap:factorization restored!


CDF-II Tag leading p-bar @ 0.02 < < 0.1

Reject (retain) 95% of ND (SD)events

detectforwardparticle

s


MiniPlug Calorimeter

About 1500 wavelength shifting fibers of 1 mm dia. are ‘strung’ through holesdrilled in 36x¼” lead plates sandwiched between reflective Al sheets and guided

into bunches to be viewed individually by multi-channel photomultipliers.


Artist’s View of MiniPlug

25 in 5.5 in

84 towers


Exclusive Dijets in DPEInterest in diffractive Higgs production Calibrate on exclusive dijets

Dijet mass fraction

X

conejj

jj M

MR

no peak!pb10534GeV25

pb27265970GeV10

0.8)(RσE jjjjexcl

DPEjetT

Upper limit for excl DPE-jjconsistent with theory: KMR 60 pb @ 25<ET

J<35 GeV


Gap Between Jets

jet???gap ΔyΔy Question

gapΔyjetΔy

5%1%/0.2/SR)s(R JGJTEV

JGJLHC

JetGapJetpp


Diffraction @ LHC

Multigap diffraction

Exclusive production of high mass states


Summary

@CDF Derive diffractive from ND pdf’s and color factors@ LHC Multigap and High Mass Exclusive DiffractionCDF2LHC Special low-lum run needed for low- and JGJ


BACKUP


The First 20 Years The First 20 Years

KG, Phys. Rep. 101 (1983) 171

XLL/PΔPξ

1

~d

d

constantyd

dσ

M

1~

dM

dσ22

POMERON: color singlet w/vacuum quantum numbers

s

M

p

Δpξ

2

L

L y

y

2ln M

slnln

y025.0dMdt

σd2

2

t


Run-I A,B: Rapidity Gap Studies

Forward DetectorsBBC 3.2<<5.9FCAL 2.4<<4.2


SD/ND Dijet Ratio vs xBj@ CDF

(x)F

(x)FR(x) ND

jj

SDjj

0.035 < < 0.095

Flat dependence


New: FDJJ() from ZEUS-LPS

Data

Fit includingcharm data

Fit withoutcharm data

ZEUS

H1

M. Arneodo, HERA/LHC workshop, CERN, 11-13 Oct 2004

Flat after subtractingReggeon contribution


-dependence: Inclusive vs Dijets

0.1)0.9m0.1,1.0(n ξ

1

β

1ξβ,F

mnDjj

g =0.5

q =0.3

Pomeron dominated

constantdξ

dσincl


SOFT DIFFRACTION

Hard Diffraction @ CDF HARD DIFFRACTION

Additional variables: (x, Q2)

seExjet

T

jetBj /

22 )(, jetTEQx

dN/d

=PL/PL =fractional momentum loss of scattered (anti)proton

Variables: (, t) or (,

t)

MX

=-lnt

dN/d

ln MX2


Roman Pot tracking


Gap Survival Probability

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

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

S =

Results similar to predictions by:Gotsman-Levin-MaorKaidalov-Khoze-Martin-RyskinSoft color interactions


Soft Diffraction Summary

M2 – scaling

Non-suppressed double-gap to single-gap

ratios

Experiment:

Phenomenology:

Generalized renormalization

Obtain Pomeron intercept and tripe-Pomeron coupling from inclusive PDF’s and color factors


Diffractive dijets

=alltowers)ET e

s

momentum loss fraction of pbar

Approx. flat at <0.1

const

overlap events

SD region

MP energy scale: ±25% →Δlogξ = ±0.1RP acceptance (0.03<ξ< 0.1) ~ 80% (Run I)


Q2-dependence of SD/ND ratio

No appreciable Q2 dependence

within 100 < Q2 < 10,000 GeV2

Pomeron evolves similarly to proton


: RP vs calorimeter

overlap events

signal region

cal distribution for slice of RP

from RP

cal = (0.94 ± 0.03)

RP

/mean ~ 30%


CDF2LHC

TOPIC STATUS

(Q2, t) dependence of DSF close to ready

Exclusive c production close to ready

Low mass states in DPE need good trigger

Exclusive b-bbar production in DPE need b-trigger

-dependence of DSF need low lum run

Jet-gap-Jet w/jets in miniplugs need low lum run

compositeΔyΔy

BFKLΔyΔyjetgap

jetgap

gapΔyjetΔy

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