k. goulianos the rockefeller university diffractive and total cross sections @ tevatron and lhc hcp...

$: K. Goulianos The Rockefeller University Diffractive and Total Cross Sections @ Tevatron and LHC HCP 2006 Duke University, NC, USA, 22-26 May 2006 CDF$
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


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


Elastic Scattering

dt

d

2

π

)(p4

R

c

GeV13b

m

1R

e~bte~dt

dσ 22


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


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


Diffractive pp Processes

Elastic scattering Total cross section

SD DD DPE SDD=SD+DD

T=Im fel (t=0)

OPTICALTHEOREM

GAP


Rapidity Gaps in Fireworks


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 (?)


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 ???


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


CDF-IRun-IC Run-IA,B

Forward DetectorsBBC 3.2<<5.9 FCAL 2.4<<4.2

beam


CDF-II ROMAN POT DETECTORS

BEAM SHOWER COUNTERS:Used to reject ND events

MINIPLUG CALORIMETER


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


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


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


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


Elastic/Total and -values: Regge fitCovolan, Montagna, and G

PLB 389 (1995) 176

Agreement with data on:

b-slopesel/T

-values

Unitarity assured


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


TOTEM experiment @ LHC

Total Cross Section, Elastic Scattering, and Diffraction Dissociation

Aim at 1% accuracy on T

RP stations

RP stations

CMS


DIFFRACTION Soft & hard diffraction

Factorization / renormalization

Multi-gap diffraction

Diffraction in QCD

Dark energy ???


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


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 !


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


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


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)


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


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


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?


HARD DIFFRACTION Diffractive fractions

Diffractive structure function

factorization breakdown

Restoring factorization

Hard diffraction in QCD

dN/d

JJ, W, b, J/


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


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


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


Diffractive Structure Function:Q2 dependence

ETjet ~ 100 GeV !

Small Q2 dependence in region 100 < Q2 < 10,000 GeV2

Pomeron evolves as the proton!


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!


valence quarks

antiproton

x=

Hard Diffraction in QCD

proton

deep sea

Derive diffractivefrom inclusive PDFsand color factors

antiproton

valence quarks

p

p


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


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


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


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

k. goulianos the rockefeller university diffractive and total cross sections @ tevatron and lhc hcp...

Documents

lhc hcp

duke university

cdf collaboration slide

tev slide

pp xgx

pp pxp

ln s x slide

optical theorem gap