Koji TerashiThe Rockefeller University

for the CDF Collaboration

Wine & Cheese Seminar, March 30th, 2007

1

Diffraction and Exclusive Production at CDF

~ Towards Exclusive Higgs at LHC ~

Motivation Run I Results Run II Results and Prospects Road towards LHC Summary

2

Outline

Non-Diffractive Diffractive

Color exchange Colorless exchange with vacuum quantum numbers

GOAL : Understand the QCD nature of diffractive exchange

3

Diffractive Physics

Exclusive (QCD)

Gluon exchange with extra soft gluon→neutralize color-flow

GOAL : Test and calibrate theoretical calculations of exclusive production

4

Exclusive Production

η

φp

p-ln ξ

p

ξ

ξ : momentum fraction of p carried by diffractive exchanget : 4-momentum transfer squaredMX : mass of system X

Strategy Characterize formation of rapidity gap(s) in events

with different gap topology Examine partonic structure using high pT probes

X

X

5

GAP

ln MX2

ξ = MX2 / s

ln s

t

Diffractive pp Interactions

Single Diffraction

Double Diffraction

Double Pomeron Exchange

Single + Double

Diffraction

ηφ

p

p

ηφ

p

p

ηφ

p

p

ηφ

p

p

14 published papers : 13 PRL and 1 PRD

6

σtotal and σelastic (not discussed today)

CDF Diffraction in Run I

‣ Pomeron trajectory : αIP(t) = 1 + ε + α’t‣ ε ≃ 0.1‣ s’ = MX2 = sξ

[ ]Flux fIP/p(ξ, t)

Single Diffraction Cross Section

d2σSD

dξdtβIPp(t)2 ξ

16π1

=1-2αIP(t) βIPp(0)g(t)( )s0

s’ ε

σIPptotal

σSD = ∫ξmin

0.1

∫∞0

fIP/p(ξ, t)σIPptotaldξ dt ~ sε ∫ξmin

0.1

dξξ−(1+ε)

~ s2ε

p

p

p

ξX

cf. σtotal = βIPp(0)2( )s0

s ε~ sε

7

Diffraction in Regge Theory

ξmin = M02/s

−

Regge Theory

σSD ~ s2ε (ε ≃ 0.1)⇒ exceeds σtotal at √s ≈ 2 TeV

Measurement‣ σSD ~ s2(0.015±0.008)

⇒ much weaker s-dependence

➡ A factor of ~10 suppressed in normalization

‣ dσ/dξ ~ ξ−(1+ε) dependence➡ Same as Regge theory

8

1000010001001 01

1 0

1 0 0

!s (GeV)

Tota

l Sin

gle

Diffr

actio

n Cr

oss

Sect

ion

(mb)

" < 0.05Albrow et al.Armitage et al.UA4CDFE710

Renormalized

Standard

f luxCool et al.

pp

f lux

"knee" at 22 GeV

CDF: 546 GeV and 1.8 TeVPRD 50, 5535 (1994)

Tota

l Sin

gle

Diff

ract

ion

Cro

ss S

ectio

n (m

b)

√s (GeV)

K. Goulianos, PLB 358,379(1995)

RenormalizationPomeron flux integral (re)normalized to unity ∫

ξmin

0.1

∫∞

0

fIP/p(ξ,t) = 1dξ dt

Soft Single Diffraction

−

DDPRL 87,141802(2001)

DPEPRL 93,141601(2004)

SDDPRL 91,011802(2003)

Event yield as a function of Δηgap or ξRegge-based MC simulations normalized to data

10

10 2

10 3

10 4

10 5

0 1 2 3 4 5 6 7

!s=1800 GeVDATADD + non-DD MCnon-DD MC

"#0=#max-#min

even

ts

10

10 2

10 3

10 4

10 5

10-6

10-5

10-4

10-3

10-2

10-1

1!p

X

MX2

Num

ber o

f Eve

nts

per "

log!

= 0

.1

DataDPE MCSD MCDPE+SD MC

#s$ = 1800 GeV0.035 % !- p % 0.095| t- p | % 1.0 GeV2

( GeV 2 )1 10 10 2 10 3 10 4 10 5 106

10 2

10 3

10 4

10 5

0 1 2 3 4 5 6 7!"0

exp="max-"minev

ents

#s=1800 GeVDATASDD + SD MCSD MC

η

φ

η

φ

η

φ

fixed

fixed

Data agree with Regge predictions in ξ-dependence 9

Soft Diffraction

DD DPE SDDFraction (or cross section) of gap events as a function of √s

1

10

10 2

10 102

103

!s (GeV)

"DD

(mb)

for #

$ >

3.0

ReggeRenormalized gap

CDFUA5 (adjusted)

10-1

1

103

sub-energy !s--, (GeV)

gap

fract

ion "#

> 3

.0 CDF: one-gap/no-gapCDF: two-gap/one-gapRegge predictionRenorm-gap prediction

2-gap

1-gap

2100

0.1

0.2

0.3

0.4

0.5

103

!s" (GeV)

Frac

tion

of E

vent

s wi

th #

p < 0

.02

CDF Data (Preliminary)Regge + FactorizationGap Probability Renorm.Pomeron Flux Renom.

Single gap rates are suppressed by O(10) Double gap rates are less suppressed

relative to Regge predictions

10

Soft Diffraction

Proposed by Ingelman and Schlein in 1985 PLB 152, 256(1985)

Discovery of diffractive di-jets by UA8 PLB 211,239(1988), 297,417(1992)

11

Probing partonic structure of the diffractive exchangeSD DD DPE

‣ W boson‣ Di-jet ‣ b-quark‣ J/ψ meson

‣ jet-gap-jet (not shown today)

‣ Di-jet

ηφ

p

p

ηφ

p

p

ηφ

p

p

Hard Diffraction

p

e

p

e

IPzIPx

p

p

p

!jetjet

"

Tevatron : σ(pp→pX) ≈ FjjD ⊗ Fjj ⊗ σ(ab→jj)

Universal parton densitiesin diffractive exchange?

Proved by J. Collins PRD 57,3051(1998)

HERA ep TEVATRON pp

HERA : σ(ep→eXp) = FjjD ⊗ σ(ab→jj)

Factorization Test

12

?

‣ hard scatteringmatrix element

‣ process dependent

QCD Factorization

WPRL 78,2698(1997)

Di-jetPRL 79,2636(1997)

b-quarksPRL 84,232(2000)

J/ψPRL 87,241802(2001)

13

Probing quark and gluon contents in diffractive exchange

p

p

pIP

W

p

p

pIP

JetJet

p

p

pIP

bb

p

p

pIP

!J/

q

g g

q/g

Hard Single Diffraction in CDF

W Di-jet b-quark J/ψ

R[ ] (%) 1.15±0.55 0.75±0.10 0.62±0.25 1.45±0.25diffincl

Diffractive production rates are all similar at ~1% relative to inclusive rates

Factorization approximately holds within Tevatron (at fixed √s)

√s=1.8 TeV

14

Diffractive to Inclusive Ratio

GLUON FRACTION IN POMERON

0

0.2

0.4

0.6

0.8

1

1.2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

D (M

EASU

RED

/ PRE

DICT

ED)

ZEUS

CDF-DIJET

CDF-WCDF-b

Gluon Fraction in Pomeron

R(m

easu

red/

pred

icte

d)

R = 0.19 ± 0.04SD production rates are severely suppressed relative to HERA

Factorization breakdown between Tevatron and HERA

R = 1 : factorization valid

15

PRL 84, 232(2000)

Factorization Breaking

p

p

p

!jetjet

"

σ(pp→pX) ≈ Fjj ⊗ FjjD ⊗ σ(ab→jj)

Determine FjjD in LO QCD using

FjjD (xBj, Q2) Fjj (xBj, Q2)σjj(Diff)

σjj(Non-Diff)R(xBj) of=

DataProton PDF

×

16

FjjD = FjjD (ξ, t, xBj, Q2)Diffractive Structure Function

β = xBj/ξ : Momentum fraction of diffractive exchange carried by the scattering parton

Diffractive Di-jet Production

Diffractive Structure Function

FjjD at the Tevatron is suppressed relative to expectations from dPDFs measured by H1 at HERA

Similar suppression as in soft SD relative to Regge expectations

Breakdown of QCD Factorization confirmed

17

CDF PRL 84,5043(2000)

P. Newman : Hera-LHC workshop, March 2007(Also, see M. Ruspa’s talk in Small-x workshop)

H1(2006)

H1(1997)

Diffractive Structure Function

0.1 1

0.1

1

10

100

CDF dataET

Jet1,2 > 7 GeV0.035 < ! < 0.095| t | < 1.0 GeV2

H1 fit-2H1 fit-3

( Q2= 75 GeV2 )

"

F#D JJ

(")

H1 2006 DPDF Fit AH1 2006 DPDF Fit B

0.1 1

0.1

1

10

100

!

FD jj(!)

from DPE/SD , 0.01 " # " 0.03

from SD/ND , 0.035 " # " 0.095

SD

SD

ND

DPE

FjjD from DPE/SD is larger than FjjD from SD/ND

gap no gap

Factorization breakdown within the Tevatron18

1.8 TeV

PRL 85, 4215(2000)

Diffractive Structure Functions from DPE and SD Data

0.1 1

0.1

1

10

100

!

FD jj(!)

CDF data, based on DPE/SD

Expectation from H1 2002 "rD QCD Fit (prel.)

FjjD measured from DPE is approx-imately equal to expectations from dPDFs measured at HERA

2nd gap less suppressed if a gapis already present in the events

QCD factorization between HERA and Tevatron restored?

19

Restoring QCD Factorization?

SD ‣ ξ, t, and Q2 dependence of FjjD

‣ Process dependence of FD(W, Z) →M. Convery’s talk

DPE ‣ ξp dependence on FjjD measured on p-side

DD ‣ Δηgap dependence for fixed large Δηjj →C. Mesropian’s talk

Exclusive ‣ di-jet, di-photon, χc

‣ e+e−, μ+μ− →L. Zhang’s talk

GOAL Further characterize diffractive structure function anddiffractive exchange Measure exclusive production and calibrate theoreticalcalculations

Results presented in this talk20

Run II Diffractive Program

21

CDF II

QUADsDIPOLEs

2m

57m to CDF

p p

DIPOLEsQUADs

TRACKING SYSTEM CCAL PCAL MPCAL CLC BSC RPS

Tracking Detectors : |η| < 2.0 Calorimeters : |η| < 5.2 Beam Shower Counters (BSC) : 5.4 < |η| < 7.4 Roman Pot Spectrometers (RPS) : 0.02 < ξ < 0.1

0 < |t|< 2 GeV2

CDF II Detector

22

MiniPlug Calorimeters

PMTs25

1/4

"1512 WLS fibers

PMTs

22 1/2"

36 PLATES

BEAM

5 1/

2"

STAINLESS STEEL SUPPORTALUMINUM1/4" THICK PLATE (3/16" PB + 2x0.5mm AL)KURARAY Y11 MULTI!CLAD 1.0mm DIA. WLS FIBER BICRON 517L LIQUID SCINTILLATOR

Electromagnetic calorimeter withhadron detection capability

➡ Good position resolution retained e+ : σposition/E = 9.2mm/√E σenergy/E = 18%/√E+0.6%

➡ Used to measure particle energy and multiplicity in 3.6<|η|<5.2

32X0, 1.3λI

Read out byWLS fibers

Built by Rockefeller Group

Among problems we had to overcome, the most challenging one is multiple pp interactions (pile-up) that spoil diffractive signatures

pCAL! pCAL!

Even

ts

10-1

1

10

102

103

104

105

106 CDF Run II Preliminary

BGSD

10-3 10 -2 10-1 1 10

RPS + Jet5 > 5 GeV) - rescaledT

seedJet5 (E

pRPS!

0 0.02 0.04 0.06 0.08 0.1 0.12

pCA

L!

0

0.2

0.4

0.6

0.8

1

1.2

0

2

4

6

8

10

12CDF Run II Preliminary

Σtowers ETe-η

√sξCAL =

ξCAL

pile-up events

signal region

Used to reject pile-up eventsby selecting ξCAL < 0.1

Linst~2×1031cm-2s-1 (not “high” lum!)

23

ξCA

L

ξRPS

Run II Challenge

Bjx

) / N

D!

"Ra

tio (

SD

/

10-3

10-2

10-1

1

10 / ndf 2

# 23.26 / 12

Prob 0.0256

Const 0.000965± 0.01031

slope 0.04419± -1.027

/ ndf 2# 23.26 / 12

Prob 0.0256

Const 0.000965± 0.01031

slope 0.04419± -1.027

10-3 10-2 10-1

6% (slope)± 20% (norm), ±systematic uncertainty:

<0.09pCAL!0.03<

|<2.5)jet$ CDF Run II preliminary (||<4.2)jet$ CDF Run I (|

Run I result is confirmed(difference at high xBj caused from different jet acceptance)

FjjD (xBj, Q2)

Fjj (xBj, Q2)RSDND (xBj) ≈

24

xBjorken-dependence of FjjD

Bjx

) / N

D!

"Ra

tio (

SD

/

10-3

10-2

10-1

1

10 / ndf 2# 23.26 / 12

Prob 0.0256

Const 0.0009656± 0.01031

slope 0.04422± 1.027

/ ndf 2# 23.26 / 12

Prob 0.0256

Const 0.0009656± 0.01031

slope 0.04422± 1.027

10-3 10-2 10-1

6% (slope)± 20% (norm), ±overall syst. uncertainty: )/2jet2

T+Ejet1T>=(E*

T, <E2>*T <E$ 2Q

<0.09pCAL!0.03<

CDF Run II Preliminary2 100 GeV%

2Q2 400 GeV%

2Q2 1,600 GeV%

2Q2 3,000 GeV%

2Q2 6,000 GeV%

2Q2 10,000 GeV%

2Q

No appreciable Q2 dependence relative to Fjj in 100 < Q2 < 10000 GeV2

Pomeron evolves similarly to proton

FjjD (xBj, Q2)

Fjj (xBj, Q2)RSDND (xBj) ≈

25

~10 GeV〈ET*〉

~100 GeV

NormalizationN

~10-4N

Q2-dependence of FjjD

2 |t| (GeV/c)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

2 |t| (GeV/c)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

/dt [

arbi

trary

uni

ts]

!d

10

102

103

104

RPS inclusive

)2~225GeV2RPS+Jet5 (Q

)2~900GeV2RPS+Jet20 (Q

)2~4,500GeV2RPS+Jet50 (Q

)/2jet2T+Ejet1

T>=(E*T, <E2>*

T <E" 2Q<0.08p

RPS#0.05<

CDF Run II Preliminarystatistical uncertainties only

)2 (GeV2Q10-2 10-1 1 10 10 2 103 104

) at |

t|=0

(arb

itrar

y un

its)

2b(

Q

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2CDF Run II Preliminary

<0.08pRPS!0.05<

RPS inclusivenorm. to unity and

2=1 GeV2set at Q

Fit t-distributions to a double exponential function :

F = 0.9eb1t + 0.1eb2t

Slope at t=0 is independent of Q2 in the range 0<Q2<4500 GeV2

Work in progress for➡ absolute t-slope values➡ larger |t| range up to ~4 GeV2

26

arbitrary normalization

t-dependence of FjjD

→M. Gallinaro’s talk

Motivated by unique potential to measure particle state produced in exclusive reaction pp→pXp

‣ JPC = 0++ state due to Jz = 0 rule‣ clean signal (no underlying event)

Primary aim is Higgs boson (and new physics)

27

p

p

p

p

gg

gHX

Exclusive Production

p

p

p

p

gg

gH

Tagging forward nucleons

➡ Higgs quantum numbers➡ mass resolution < 2~3 GeV using missing mass method: MH = (pin+pin−pout−pout)1/2

SM Higgs boson (MH=120 GeV):σ(pp→pHp) < 0.1 fb at Tevatron, = 1~10 fb at LHC

Calibrate theoretical calculations using exclusive processes with higher cross sections

28

Standard Model Higgs Boson

29

Exclusive Di-jet/Di-photon Exclusive Di-lepton

p

p

p

p!

!

+l-l)µl=(e,

p

p

p

p

gg

g

!j, !j,

Potential to improve LHCluminosity measurements

Validate analysis method

QED-mediated processCross section well known (< 1%)

Exclusive Production at CDF

Analysis requires - protons do not dissociate- only e+e− produced (ET>5GeV, |η|<2) and nothing else

Good control sample for pp→pγγp search

30

p

p

p

p!

!

+e-e

Detailed analysis performed to set thresholds for each detectorEffective Luminosity : 46±3 pb-1 (out of 532 pb-1)

Exclusive e+e− Production

Et = 15.62 GeV

!

-4-3

-2-1

01

23

4

"

0100

200300

TE

0

10

20

16 candidate events observed

31

ET1 = 15.2 GeVET2 = 14.6 GeV

of leading electronTE0 5 10 15 20 25 30

of s

econ

d el

ectro

nTE

0

5

10

15

20

25

30 CDF Run II PreliminaryData (no BG subtracted)LPAIR MC

(rad)! "2.8 2.85 2.9 2.95 3 3.05 3.1 3.15

)! "

1/N

dN/d

(

00.10.20.30.40.50.60.70.8

CDF Run II PreliminaryData (no BG subtracted)LPAIR MC

CDF Run II

Exclusive e+e− Production

32

Number of Additional Clusters0 10 20 30 40 50

Num

ber o

f Eve

nts

02468

101214161820 Candidate Sample

LPAIR SimulationBackground Fit

a)

σMEAS. = 1.6 +0.5-0.3(stat) ± 0.3(syst) pb

agrees with LPAIR Monte Carlo (QED) prediction σLPAIR = 1.71 ± 0.01 pb

PRL 98, 112001 (2007)

16 candidate eventsBackground: 1.9±0.3 events 5.5σ observation

Good agreement serves to validate analysis method

CDF Run II

Exclusive e+e− Production

Gluon exchange process factor 3~4 uncertainty in σ

33

Can be used to calibrate exclusive Higgs cross section

Analysis requires - same event selections as pp→peep (except etrack veto)- only γγ produced (ET>5GeV, |η|<1) and nothing else

p

p

p

p

gg

g!!

Exclusive Di-photon Production

3 candidate events observedExclusive Di-photon Production

34

ET1 = 6.8 GeVET2 = 5.9 GeV

CDF Run II Preliminary (rad)!"2.8 2.85 2.9 2.95 3 3.05 3.1 3.15 3.2

)! "

1/N

dN/d

(

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7 CDF Run II PreliminaryData (no BG subtracted)ExHume MC

)2Invariant Mass (GeV/c0 10 20 30 40 50 60

!!1/

N dN

/dM

00.20.40.60.8

11.21.41.6

CDF Run II PreliminaryData (no BG subtracted)ExHume MC

3 candidate events including exclusive π0π0 or ηη (π0,η→γγ)Background : 0.09±0.04 events 3.7σ evidence for combined exclusive (γγ, π0π0, ηη) signal EM shower analysis indicates 2 of 3 events are likely γγ

σ(pp→pγγp) < 410 fb (95% C.L.)Khoze, Martin, Ryskin : σγγ~40 fb (factor 3 uncertainty)

Assuming 2 events are exclusive γγ,σ(pp→pγγp) = 90 +120-30(stat) ± 16(syst) fb

35

Exclusive Di-photon Production

→M. Albrow’s talk

Exclusive Di-jet Production

Select inclusive DPE di-jets : p+p → p+X(∋2jets)+gapReconstruct di-jet mass fraction : Rjj = Mjj/MX

Look for data excess over DPE di-jet background as Rjj→1

Strategy

36

Rjj→1 ０ η→+

pp

Jet Jet

０ η→+

pp

Jet Jetdetected

not detected

X

➡ Signal (Rjj=1) smeared due to shower/hadronization effects, NLO gg→ggg, qqg contributions, etc.

➡ DPE di-jet background shape from POMWIG MC simulation (⇒ Uncertainty from Pomeron PDF)

gap

37

X / Mjj = MjjR0 0.2 0.4 0.6 0.8 1

dN /

N

10-4

10-3

10-2

10-1 DPE data (stat. only)

Background

POMWIG + BackgroundH1!POMWIG : CDF

POMWIG : CDFPOMWIG : H1-fit2POMWIG : ZEUS-LPS

CDF Run II Preliminary

Excess observed over MC simulations with varied PDFs

!

-4-3

-2-1

01

23

4

"

0100

200300

TE

0

5

10

Et = 16.94 GeV

ET1 = 33 GeVET2 = 31 GeV

Rjj = 0.96CDF Run II Preliminary

Di-jet Mass Fraction

Binned likelihood fits (MC normalizations as free parameters)

Signal MC ExHuMECPC 175,232(2006)

Exclusive DPE (DPEMC)CPC 167,217(2005)

CDF H1CDFH1-fit2ZEUS-LPS

22.1±1.8 %21.7±1.8 %24.7±2.0 %24.3±2.0 %

23.0±1.9 %22.6±1.9 %26.0±2.1 %25.4±2.1 %

X / Mjj = MjjR0 0.2 0.4 0.6 0.8 1

Even

ts

0

100

200

300

400

500CDF Run II Preliminary

DPE data (stat. only)H1!POMWIG: CDF

ExHuMEBest Fit to Data

| < 5.9gap"3.6 < | > 10 GeVjet2

TE < 5 GeVjet3

TE < -0.5jet1(2)"

1.8 %± = 22.1 exclF(stat. only)

X / Mjj = MjjR0 0.2 0.4 0.6 0.8 1

Even

ts

0

100

200

300

400

500CDF Run II Preliminary

DPE data (stat. only)H1!POMWIG: CDF

Exclusive DPE (DPEMC)Best Fit to Data

| < 5.9gap"3.6 < | > 10 GeVjet2

TE < 5 GeVjet3

TE < -0.5jet1(2)"

1.9 %± = 23.0 exclF(stat. only)

stat. error only

databkgdsignalfit

38

⊕

MC Fit to Rjj Shape

39

X/Mjj = MjjR0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

F0.5

1

1.5

CDF Run II Preliminary

Systematic Uncertainty1F

= POMWIG + BackgroundinclMCH1-fit2)!(CDF

<0.4jj at Rinclnormalized to Data

: stat. error only2F

"<0.4)jj(Rbc/inclF# / bc/incl F$ 1Fincl / Dataincl MC$ 2F

LO exclusive gg→qq suppressed due to Jz = 0 rule Look for the suppression in heavy flavor jet fraction vs Rjj

X/Mjj = MjjR0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

!<0

.4)

jj(R

bc/in

clF"

/ bc

/incl

F 0.5

1

1.5

CDF Run II Preliminary

DPE data (SVT)Systematic Uncertainty

(RAW) > 10 GeVjetTE

| < 1.5jet#|

X / Mjj = MjjR0 0.2 0.4 0.6 0.8 1

dN /

N

10-4

10-3

10-2

10-1

DPE data (stat. only)H1!POMWIG : CDF

BackgroundPOMWIG + Background

H1!CDFCDF Run II Preliminary

inclMC

incldata

HFdata

incldata

The two results are consistent with each other

Exclusive Di-jet Signal

(GeV)minTJet E

10 15 20 25 30 35

>0.8

) (pb

)jj

(R e

xcl

jj!

-110

1

10

210

310

31 ×KMR

Hadronizationuncertainty

CDF Run II PreliminaryData corrected to hadron level

ExHuME

Exclusive DPE (DPEMC)

minT > Ejet1, 2

TE| < 2.5jet1, 2"|

< 5.9gap"3.6 < < 0.08p#0.03 < stat. syst. uncertainty$stat.

40

Khoze, Martin, Ryskin at LO parton-level (factor 3 uncertainty)

hep-ph/0507040

Exclusive DPE (DPEMC)

ExHuME

Measured σjjexcl prefers ExHuME and KMR calculations

Exclusive Di-jet Cross Section

Exclusive Di-jet Mass Reach

CDF pp→pjjp reaches Higgs mass range!!pp→pHp at LHC

41

)2 (GeV/cjjM20 40 60 80 100 120 140 160

2G

eV/c

pb

jjdM

excl

jj!d

-310

-210

-110

1

10

210 ExHuME (Hadron Level)DefaultDerived from CDF Run II

)minT (Eexcl

jj!Preliminary

| < 2.5jet1, 2"| < 5.9gap"3.6 <

< 0.08p#0.03 <

Systematic Uncertainty

Unfold measured σjjexcl to dσjjexcl/dMjj using ExHuME

Lum = 1033-34 cm2 (Low β*)

MX2 = ξ1 ξ2 s

TOTEM+CMSSimilarly in ATLAS

FP420

P. BusseyW. Plano

⇒ FP420 project

ATLAS

CMS

42

Acceptance ξ MX (GeV)

220m+220m 0.02-0.2 200-2000

420m+420m 0.002-0.02 30-200

pp→pHp Acceptance at LHC

MH (GeV) 120 140 160

H→WW(*)→lνjj (fb)proton tagger acceptance

0.25 0.63 0.83

#Events at 30 fb-1

ATLAS lepton trigger 1.1 3.6 5.8

B .Cox et al., Eur. Phys. J. C45, 401 (2006)

43

Exclusive Higgs→WW(*) at LHC

p

p

p

p

gg

gH

H→WW(*) for MH=135-200 GeV MH resolution ~ 2 GeV (any W decay)

by tagging forward protons

“Very small backgrounds” (continuum within ΔMH)

Feasibility study and R&D for the proton detector at 420m from the IP in normal high luminosity running

‣ R&D fully funded‣ Aim is to install detectors in Fall 2008

44

www.fp420.com

FP420 Project

Fixed Beampipe

BPM

BPM

Detector Space

Cryogenic Lines

45

Mechanics at 420m

Test beam at CERN in Sep 2007

46

Fast Timing DetectorsReject pile-up backgrounds by measuring Zvertex using time-of-flight information

UTA, Albert, FNAL, Louvain

Silicon Detectors

47

Both soft and hard diffraction results appear to point to a picture of diffractive exchange;

Universality of rapidity gap formation Composite ‘proton-like’ structure Factorization breakdown and restoration

Run II studies will help understand the QCD aspects

Exploring physics with exclusive production

Perturbative QCD appears to work well CDF results encouraging for future prospects at LHC Ongoing efforts to install proton taggers at LHC

→ FP420 project

(soft ↔ hard)

Summary