mike albrow diffraction in high energy collisions cern june09 1 diffraction in high energy...

$: Mike Albrow Diffraction in High Energy Collisions CERN June09 1 Diffraction in High Energy Collisions Mike Albrow (Fermilab) FNAL-CERN School June 2009$
1Mike Albrow Diffraction in High Energy Collisions CERN June09

Diffraction in High Energy Collisions

Mike Albrow (Fermilab)

FNAL-CERN School June 2009


Diffraction in High Energy Collisions(a.k.a Vacuum Exchange, Vacuum Excitation)

Mike Albrow, Fermilab

Landscape: from elastic scattering to p + H + p

Basics: Elastic and Total x-section, diffractive excitation

Double Pomeron Exchange = Vacuum Excitation

Central Exclusive Production at Tevatron

Central Exclusive Production at LHC : etcllWWH ,~~

,,


From elastic scattering to exclusive Higgs boson production

H

p

ppp

pp

p

p= gluon

But these are related processes! We will get to that.

About 25% of σ(total) About of σ(total)1310

Standard Model: Fundamental matter particles are fermions:Spin ½ leptons and quarks u,d,s,c,b,t

and force particles are bosons: Spin 1 γ, g, W, Z (& spin 0 H)(In principle also Spin 2 graviton, but negligible so far, …)

τμe ντ,,νμ,,νe,

Exchanges Elastic: Q = 0, colour = 0, J >=1 @ H.E.


In ancient times, pre-QCD (1960’s), Theory of strong interactions being developed: “Regge Theory”Pre-quarks, pre-gluons, pre-deep inelastic scattering.

Based on scattering amplitudes “S”(Square cross sections) S(s,t)S(s,t) required to be:Analytic (no singularities)Unitary (no probabilities > 1)Crossing symmetric (s t)

0

p n

s t

t-channel exchange dominatedby virtual:

)()( 0 pnnp All good things!

This still gives the best description of low-E reactions e.g.

But: Effective angular momentum / spin of exchange α(t) and complex

np 0

QCD became dominant, Regge theory almost left behind.


Total cross sectionElastic scatteringDiffractive excitation

Much of strong interaction physics is here.Not (yet) described by/understood in QCDWhen Q^2 small α(Q^2) large, “non-perturbative”

COMPETE Collbn fits

LHC

Expect σT ~ 110 nbHow to measure?Total rate inelasticNeed LuminosityElastic scatteringDedicated expt: TOTEM

Strong coupling notRegge spin!


ijT

i

j=

i

j j

i2

=

dt

d ijel

α(t=0)

α(t)

ii

jj

jj

ii 2

Total cross section and elastic scattering closely related:

Elastic scattering described by amplitude:

Total cross section by Imaginary part of forward scattering amplitude.Regge theory:

2|),(| tsfdt

d ijel

)0,( Im.4)( sfsijT

k

kjikijT

kss ]1)0([)0()0()( ]1)([222

16

)()( t

k

jkikijel ks

tt

dt

d

Optical theorem

Couplings at vertices and propagator (~ Feynman diagrams)

k

k


Relation between σT and dσ/dt exploited at LHC by TOTEM

CMS

Measure small angle elastic and total rate simultaneously:

Can derive both σT and machine luminosity!Calibrate luminosity monitors. Coulomb scattering: known cross section but extremely hard at LHC.

Another QED process may be better for luminosity calibration: μμγγ (later)


Total and elastic cross sections: fall then rise (universal)

ln s

RP

R(t), P(t)

R (Reggeon) = sum of all allowed meson exchanges P (Pomeron) = (?) sum of all allowednon-meson (gg etc?) exchanges. Glueballs

qq ρ, ω, ρ etc

( )pp

iα (t=0) -1

-0.45R

+0.08P

Two terms: s

α ( 0) 0.55 s

α ( 0) 1.08 s

t

t

2α(t=0) - 2Total Elastic : ~ s

s t

α(t) effective spin of exchange


k

kjikijT

kss ]1)0([)0()0()(

If α(0) (~ J) > 1 total and elastic cross sections rise with s < 1 fallAt low energy ρ-exchange dominates, butAt high energy (rising cross sections)another strongly interacting exchange with α(0) > 1 (1+ε) dominates. POMERON IP

5.0~)0(

15.1~)0(IP

)(tIPlongitudinal rapidity y

p p

p

p

Other exchanges with J >= 1:Photon γ and Z (between q, p would break up)

IP


12 2313

12 23

β + ββ =

1+β βtanh a tanh b

tanh (a+b)1 tanh a tanh b

β

y

12 12So: identify β with tanh y

For small values speedand rapidity y are identical

β

As β 1.0 y

Rapidity

-10rapidity = 0 rapidity ~ 10Rapidity Gap

Relativistic speed addition Hyperbolic tanh addition

z

z

pE

pEy ln

2

1

2tanln)0m(

y


pp elastic scattering at CERN ISR.Note “diffraction pattern”

Small t, exponential, ~ 1/”size of p”Large t ~ << 1 fermi, structure

VERY small t, γ-exchangeLarge distance ( several fm)Coulomb beats strongCoulomb scattering

Coulomb cross section is ~ known (QED) … so Lumi calibrator


At LHC large angle elastic scattering uncertain!

Fig. from TOTEM (Latino)

p

p

ggg

0.1 fm

Proton structure intermediate between “point-like” andparton (q+g) beam.If 2 q scattered through “large”angle, 3rd must also orp breaks up.

A handle on IP in q/g terms.


Rapidity gaps, with (almost) no Regge theory

The mother of all rapidity gaps Δy …. Elastic scattering:

Gap = no particles:

= 24.4 LEP e+e-= 8.4 ISR pp= 15.3 TeV pp= 18.6 LHC pp

epm

s

/beam lny

epm

sy

/

ln.2

t

Rap-gap cross sections go like: yy eey ).1J().1)0(( ~~)( Thus: over large gaps exchange has J >= 1, Q = 0, color singlet.Only 2 possibilities: Photon γ (in ee and pp and ep)

Gluon (ep and pp) … ?color!!? Cancel it with >= 1 other gluon. Call it pomeron (gg) α(0)=1+εPomeron has C = +1 (2 gluons OK). C = -1 OK with (ggg) : odderonZ obeys the above rules, OK in e+e- but p inevitably break up.


Large ( >~4) rapidity gaps only possible by (t) exchange of 4-momentum with:

No color or charge, and effective spin at t ~ 0 >= 1. J = 1, α(0) >=1. But (a) we have such large gaps in strong interactions (b) QCD is THE theory of strong interactions. Unlike QED, there is no elementary (q,g) object with these properties. (c) In QCD, with Regge theory to describe exchanges of states in the t-channel, only >= 2 g exchange can work.

gg (C = +1) Pomeranchukon Pomeron IPggg (C = -1) Odderon O(not yet detected. α < 1 ?)

Isaak Pomeranchuk1913 - 1966Tullio Regge


)/(.

12

2

sMddt

df

Single Diffractive Dissociation : at low energies ...,, Knpp

At ISR energies 7.4 22-63 GeV found scaling high x_F peak.Diffractive excitation of high mass “states”

s

sM

sMxs

M

p

pxx

F

Beam

zFeynmanF

22.0~

05.0~)1(

95.0~

max

max

2

)( Fxp

Mts


PS 7.4 --- 1.6 resonancesISR 63 --- 14Tevatron 1960 --- 430 Jets/W/ZLHC1 10,000 --- 2200 top ??

Diffractive excitation range (“rule of thumb”) sM 22.0~max

smaxM

(GeV)

p

IP

p

p-IP total cross sectionoptical theorem :p-IP elastic scattering

IP .. at high MIPIP

2

ln2 (ln 3)

3

2

ln ln 3

20

1 0.05

X

ss

X

XF

M s

e sM e

e

Mx

s


Ingelman-Schlein description of high mass diffractionSDE = Single Diffractive Excitation

Suppose IP has constituent (q,g) structure F(Q2,β=x)Go into frame of X, and look for jets. Kinematics tells parton momentum fractions β.

Jets in SDE observed at CERN SppS Collider (not v. high ET)ET > 20 GeV jets in CDF, D0 at Tevatron.

X

J

J

p IP

( )1 J JBj T

jets

x E es

PARTONBj

PROTON

px

p


Diffractive Di-Jets and Diffractive Structure Functions

pSeen in

Roman Pots

1xp T

particles

E es

( , conservation)zp E

Curves normalized here

At this Luminosity, pile-updominates pJJ trigger.Require(effectively rap-gap on pbar side)

xp p

1 zp

beam

p

p

Excluding p

SDE of hard states, eg t-tbarrequires no pile-up to associatefwd p with t-tbar event.


Single Diffractive Di-Jets p-JJ cont.

4-vectors

t-distribution ~ independent of

tRatio of diffractive : non-diffractive

structure functions

2 2( ) ( )BEAM OUT Tt p p p p

( )TE J


HERA (ep) Deep Inelastic Scattering & Diffractive DIS

2 2 22 2F ( , ) ( ) ( , , , )diff

qq

x Q x e q x F x Q t The normal structure function conditional on leading proton (or gap)

Defined independently of notionof the exchange (“pomeron”)Measured in detail by H1 and ZEUS

Interpretable as measuring thestructure of the pomeron

Bjx

JJ

-yT

jets

4F (x) = x{g(x) [q(x)+q(x)]}

91

x = E es

CDF: measured with jets

Rapidity gaps suppressed in ppcompared with ep. Gaps don’t survive additional interactions.

“Rapidity Gap Survival Probability”Bjx


Diffractive (SDE) production of W & Z (CDF)

About 1% of all W & Z at Tevatron produced diffractively q / qbar in IP at Q^2 ~ M(W)^2

W

p stays intact

0.03 < xi < 0.10|t| < 1 GeV2


Diffractive production of Z (SDE) at Tevatron

Diffractively produced Z have small pT and y opposite p


Rapidity Gaps Between Jets : JGJ

y

J J

Predicted by Bjorken.Observed by D0 and CDF in Run 1 (1995)

Charged track multiplicity in central 2.5 – 4.0units of rapidity between jets <ET> ~ 65 GeV.0.85% +/- ~ 0.24% have gaps. [D0 < 1.1% @ 95% CL]

Is high-Q2 q/g scatter by color-singlet?BFKL Pomeron (mostly)?

J

J J

J

...or by single g, with softcolor exchange across event?

GAP

Early study at LHC?


BFKL and Mueller-Navelet Jets

Color singlet (IP) exchange between quarksEnhancement over 1g exchange – multiRegge gluon ladderJets with large y separation …Δy >~ 5n minijets in between (inelastic case)Large gap in between (elastic case)

TMeasure fn(η, p , s, Δη)Fundamental empirical probe of new regime:non-perturbative QCD at short distances.

S S

Cross section enhanced

4 ln 2α 0.5 for α 0.19

~ ln ~ 3 4

cBFKL

s

t

N

sn

t

q

q

gg


Central Diffractive Production or Double Pomeron ExchangeRemember:

p p

p p

IP

Double-triple-Reggeor Quintuple Regge:Must happen &rate calculable in RT

IP + IP IP + IP elasticOptical theorem IP + IP X total cross section

p pX

units3~y units3~y(better > 4) rapidity gaps = no hadrons p

2p m

sln2

m

sln

Full range:

At LHC(10) Δy(p-p) = 18.5. 18.5-6=12.5

GeV 520~e~(max)M

5.12GeV)1(~E

Mln2

6.25X

T

X


Vacuum Excitation (Lab frame)

p

p

p

pp

pp

G

J

J

1)

2)

3A)

3B)

1536 TeV

vacuum vacuum

Soft recoil, no excitation,no forward pion production, ...

all

Vacuum = Physics


GeV 520~e~(max)M

5.12GeV)1(~E

Mln2

6.25X

T

X

Mass range of central diffraction (DPE) scales like √s, ~ 0.05 √sAt ISR, 3 GeV / 63 GeV … resonances, glueball searchAt Tevatron, 100 GeV / 1960 GeV … jetsAt LHC, 500 GeV/10TeV 700 GeV/14 TeV … WW, ZZ, H …


Central Exclusive Production (AFS at ISR)

Structures not well understoodbeyond f(980). Not studied at higher

No ρ

0 (980)f

All σ cut by f0?

G(1500)??

s

G PC + ++I J =0 even

Coherent scatteringα stay intact. In LHC Au + Au(e.g. ALICE):

can be IPor photon(more likely)

Au

AuAu may also fragment


Central diffractive production or Double IP Exchange at Tevatron

M(max) ~ 100 GeV : Jets

pmeasured in Roman pots

Rapidity gap>~ 4 units

Q: Is IP just a soft mush of q and g, or sometimes leading g + colour bleaching?Di-Jet mass fraction needs a “hard” component, with IP ~ 1 gluon + soft g/gg/…


Component of pomeron that is leading gluon

g + g J + J g + g g + g g + g H c b

c-loopb-loopt-loop

H

b

c

p + p p + H + p @ LHC& nothing else produced!

p + H + p should happen at a detectable rate:Measure p very precisely mass of central state (e.g. H) σ ~ 2 GeV

Central state must have C = +1, P = +1, Even spin (0, 2 distinguishable)Width can be measured if > ~ 3 GeV. Close states (e.g. h, H in SUSY) can be separated.

Need precision measurements of protons, together with central H-like event.

Even g + g γ + γ

50%

410~

p

dp


Central Exclusive Production

pp p + X + p where X is a simple system completely measured

p p At CERN ISR

Glueball Search

At Tevatron & LHC

gg through q-loops (box) + color bleaching (g)

W

W

; ,

; ,

WW H WW H ZZ

H bb BSM WW SUSY etc

IP IP G

bc ,


32

Exclusive Di-Jets

“Almost” exclusive di-jet,Two jets and nothing else

0.8JJ

CEN

M

M

(~ polar angle)

(azimuth) Transverse

Energy TE

JETJET

else nothing~ pJJppp

Observed in CDF, QCD tests& related to p+H+p

Interesting QCD: gap survival, Sudakov factor Nearly all jets should be gg …. qq suppressed by M(q)/M(JJ) (Jz=0 rule)

Gluon jet physics.

p JJ

GAP

JJJJ

X

MR = 1.0

M


33

c0c

J/ψ

γ

μ+

μ-

& nothing elsein all CDF

-7.4 < |η| < + 7.4

Added to CDF: Beam Shower Counters BSC:Scintillator paddles tightly wrapped around beam pipes.Detect showers produced in beam pipes if p or p dissociate.e.g. 8 + 10 counters

If these are all empty, p and p did not dissociate (or BSC inefficient, could estimate from data)but went down beam pipe with small (<~ 1 GeV/c) transverse momentum.

pp

4.7||2.5

CDFcentral

BSC (size greatly exaggerated!)

- 50 m

CDF measured exclusive c J/ψ + → μ+μ-


pppp

402 events


Now allow photons: EmEt spectrum with J/ψ mass cut:

Empirical functional form

MC also estimates only few % of under the cut

65 events above 80 MeV cut.3 events below (estimated from fit)4% background under J/psi# = 65 +/- 8

4039:not do ψ(2S)

352286 :photons have J/ψ

γJ/ψχ c

cχ

γJ/ψχ c

several""factor y Uncertaint

nb 90 :prediction (Durham) KMR

nb101078| 0 ydy

d


Dimuons: Upsilon Region

Invariant Mass 0 associated trackspT(μμ) < 1.5 GeV/c

CDF Run II Preliminary

CDF Run II Preliminary

Trigger: μ+μ- |η|<0.6 , pT(μ) > 4 GeV/c

Inclusive

Search for/measurement ofphotoproduction of Y, Y’(not before seen in hadron-hadron)

Status: Candidates:analysis in progress.QED continuum checkY : cf HERA (we resolve states)Can we see ?

Y(1S)

Y(3S)

Y(2S)

γΥχ b


Categories of Diffraction at LHC

p

s2ln 19.2 (cf 15.2 at Tevatron)

my

Can have a 4-unit gap with 2 TeV SD

Can have (VF)J – G6 – (VF)J

Can have 2 x 3-unit gaps with 700 GeV DP

Can have p-G3-X-G3-X-G3-p with M(X) ~ 12 GeV


Exciting the vacuum with photons

γ Doesn’t work!E-p conservation forbids it;except for v. short times(evanescent)

γγ

Does work!E-p conservation allows it;Energy injection promotes loop to reality.

Heirarchy: ,...?tt,W,...Wμμetc.),π(&qq,ee 0

γ

γ

How do e,μ,τ,q…know what mass to have?


Photon “beams” radiated from electrons and protonsLEP etc: e+e- (~ background free)HERA: e p (more background, little done)pp/ ppbar: Very high b/g … Seen in CDF γ

e,p

ee

Phys.Rev.Lett 98,112001(2007)

2GeV/c)μM(μ

μμ

PRL 102, 242001 (2009)

PRL May 2009

μμeeμμ

inel12σ103~pb0.24~σ

Tevatron as a collider!


E not ET!

CLC BSC

M(ee) = 49.3 GeV/c2 |Δφ-π| = 6 mrad = 0.34 deg, pT(ee) = 210 MeV

M reach Tevatron >~ HERA, LEP !M reach LHC ~ 300 GeV –ishIncludes γγ → WW (~ 50 fb)

pb 0.256QED cf

pb 24.0

4||,GeV/c40

)(

(LPAIR)

13.010.0

2

μμor

M

peeppp

High mass γγ→e+e- event in CDF


All our measurements agree with QED: So what?

1) It shows we know how to select rare exclusive events in hadron-hadron environment2) No other h-h cross section is so well known theoretically except Coulomb elastic (inaccessible).

Probably best possible Luminosity calibration at LHC e.g.3) Outgoing p-momenta extremely well-known (limited by beam spread). Calibrate forward proton spectrometers.4) Practice for other γγ collisions at LHC:

.,..~~

,WWγγ ll

2 |η| and GeV 10)μM(μ

withpb500in events 4400-

1

Luminosity calibration at LHC


Khoze, Martin and Ryskin, hep-ph/0111078, Eur.Phys.J. C23: 311 (2002)KMR+Stirling hep-ph/0409037

36 fb

-1T~ 40 events per fb with p (γ) > 5 GeV/c & |η| < 1.0

& much smallerqq

Exclusive 2-Photon Production

Tevatron

Claim factor ~ 3 uncertainty ; Correlated to p+H+p

H

Phys.Rev.Lett. 99,242002 (2007)

TE ( ) > 5 GeV; | ( ) | 1.0 3 candidates, 2 golden

12Note : 2 10 !MEAS INEL


Exclusive Z production : CDF SearchAllowed in SM (like V)but ~ 0.3 fb (Motyka+Watt)

Could be enhanced by BSM loops

2.2/fb : 318K μμ&ee M > 40 GeV; 183K in Z window 82-98 GeVRequire no other interaction, no additional tracks, all calorimeters in noise (E)

8 with BSC empty

Interesting?!-IP-Z eff.coupling.ZOOM IN to see how!

LHC) @ (13fb

0.3fbTheory )σ(Z

C.L.) (95% pb 0.96)σ(Z

excl

excl

~ record E()


Central Exclusive Production of Higgs ?

Higgs has vacuum quantum numbers, vacuum has Higgs field.So pp p+H+p is possible in principle.Allowed states:

Process is gg H through t-loop as usualwith another g-exchange to cancel colorand even leave p’s in ground state.If we measure p’s (4-vectors):

H

2CEN 1 2 3 4M ( )p p p p

+ - ±Even for H W W l νJJ !

Aim: to be limited by incoming beam momentum spreadRealistic; ~ 2 GeV

p -4σ10 0.7 GeV

p

PC ++I J =0 even

J >= 2 strongly suppressed at small |t|

t

( ) 2 GeV per eventHM


Features of pp p + H + p at LHC

1) S:B can be high, > 1, even for H bb

2) Mass resolution ~ 2 GeV/event, for any final state

3) Quantum numbers determined, e.g.

4) If width >~ 3 GeV, directly measure width.

5) In MSSM can have close h,A,H. Then A excluded, h-H resolved.

6) If

0 (and 1 forbidden)CPJ

11 10 30Ae 300Ae events in 30

(Ae = Acceptance × efficiency 30%)

10 100 events (SM; maybe more in BSM)

fb fb

di-jets are suppressed by 0 rulezbb J


Central Exclusive H Productiongg fusion: main channel for H production.

Another g-exchange can cancel color, even leave p intact. p p p + H + pTheoretical uncertainties in cross section, involving skewedgluon distributions, gluon k_T, gluon radiation, Sudakov ff etc.

+ - + -

2 2 21 2 3 4 H

H(160) W W p e μ p

MM ( ) M

T

p p p p

Nothing elseon emu vertex!

Price ~ 1/2000 – 1/10000 σ (excl) ~ 1 – 10 fb cf ~ 20 pb


FP420 : Forward Protons 420m & 240m from CMS & ATLAS

CMS

CMS: Inner Vacuum Tank insertion

420 & 240m 240 & 420m||| ||| ||| |||ATLAS

; ,

; ,

WW H WW H ZZ

H bb BSM WW SUSY etc

ATLAS


~ 8 m

pBEAM

BPM BPMQUARTIC

~ 8 layers10um x-ypixels

3 mm

ResolutionRad hardnessEdgelessnessSpeed, S/NAvailabilityEnthusiasts!

TOF

Z

( ) 4.2 2.1 mm

cf (interactions) 52 mm

z

6mm(y) x 24mm (x) covers distribution

GASTOFMCP

QUARTIC

FP420 = Forward Protons 420m from x … also 240m under study

Best ever spectrometers!420 m vacuum, 120m 8T dipoles, ~10μm origin (x,y), 1 μrad track

3D- silicon ~ 8 μm over 8m.Fast timing P-U reduction factor ~ 25Normal low-β, design for 10^34

Detector area6mm x 24 mm

32.1

2

mmmm

420m too far for L1 triggerlatency. 240m not, but > M. inefficient, other channels OKbb


H[ ](M ), s = 14 TeVpp p H p

What is exclusive H cross section?

Calculation involves:gg H (perturbative, standard, NLO)Unintegrated gluon densitiesProb.(no other parton interaction) (“Gap survival”)Proton form factorProb.(no gluon radiation no hadrons) Sudakov Suppression

( ). ( ')i ig x g x

Durham Gp: Khoze, Martin, Ryskin, Stirlinghep-ph/0505240 ++

σ ~ 3 fb (M(H)=125 GeV)“factor ~ 3 uncertainty”

100 fb^-1 ~ 100-1000 Ae events(Ae = acceptance, efficiency)

Other estimates differed by “large” amounts! But exclusive c etc is a check.

Exclusive


Cross section for p+p p + SMH + p at LHC, x branching fractions:

Small (~ fb) but S:B can be high.

ExHuMe “verified” by 2-photon, & JJ < 140 GeV : bbar, > 140 GeV : WW(*)

FP420 Acceptance fn. Mass: (a) 420+420 (b) 420+240

(a) (b)

c


Simulations of SMH b-bbar signals & backgroundCox, Loebinger and Pilkington arXiv:0709.3035 (JHEP)

(a) (b)

(a) 300/fb = 3 years at 10^34, 420+420, L1 trigger on jets, muons, 25 kHz(b) Same with no pile-up background – very high resolution p-timing

... and if 420+420 in L1 trigger

future upgrade in latency?


l

J J

p p

JJM

WW*

Can use ~ 50% of WW (all but JJJJ)

, , ,WW l JJ l e SMH(135-200) WW(*) … Various missing masses

!! Unfortunatelyvery few events (SM)

Durham Gp: Khoze, Martin, Ryskin, Stirling hep-ph/0505240

(*)

(*)

(12 34JJ ) 0( )

(12 34JJ) (even for )

( )

W

W

MM l M

MM M

M JJ M

H(180) ZZ (BR ~ 10 )

(12 34 ) ( ), ~ 2 GeV!M

l l l l l l

MM l l M Z

μ(W)WWγγ Also (50fb)


Non-SM cases : no Higgs? MSSM Higgses?

1) No SMH? Can we exclude? Suppose measure 100 exclusive in CMS. (M() > 10 GeV) predict p+SMH+p to ~ 20% (trigger study in progress) Suppose expect (say) 100 pHp events in 30 fb^-1, see < 40. Conclusion?

2) No SMH or MSSM-Hs? WW physics becomes very interesting!

+ -

WW

via 50fb (precisely known in SM)

dW W Final State Interactions distort , visibly? New physics?

dM

pp p W W p W W

W

fsi

3) In case of SUSY, Forward p-tagging can be crucial! Cross section can be much higherthan SMH. Decays to enhanced.A(CP –ve) highly suppressed.

bb

Kaidalov Khoze Martin Ryskin hep-ph/0307064

Preview of ILC/CLIC physics


Can have {h, A, H} close together in mass (few GeV)Hard to resolve by inclusive production.

Exclusive advantages: higher production than SM, A highly suppressedExcellent mass resolution could separate h and H (unique)

Excellent mass resolution could even measure H widths (if ~ few GeV)

J.Ellis, J.S.Lee and A.Pilaftsis, PRD71:075007, hep-ph/0502251Durham Group (KMRS)

MSSM

H

h

A


Summary

Strong Interaction well understood at large Q2 (QCD)but most interactions difficult to describe:Total cross sections, elastic scattering, diffraction dissociation…Regge theory has some validity but connection to QCD obscure.

Hard interactions : Jets, W, Z … provide a tool (probing pomeron)

Pomeron has a hard component: g (most momentum) + (soft) g/ggThis allows ~ “tagged gluon beams” at LHC, & γ-beams

Measuring p + p p + X + p new window on SM & BSM physics

....,~~

,,,, llHhWWllXFP420/240 project in CMS & ATLAS

Warm-up: Measure diffractive JJ, W, Z, γγ at LHC


Thank you

Back-ups


e.g. Schafer and Szczurek: arXiv:0705.2887 [hep-ph]

Some predictions for J/psi photoproduction: Machado,Goncalves 3.0 nbMotyka and Watt: 3.4 +- 0.4 nbSchafer & Szczurek ~ 2.8 nbNystrand 2.7+0.6-0.2 nb

Our result: 3.92 +- 0.62 nbTak

e 3.

0 +

- 0.

3Y is much lower.Allow Pile-Up (x 10)More data (x 3)More Δy (x >4)

(95%) J/ψOIPfor nb 2.3 )(J/ 0y|dy

dσ

(CDF) nb 0.623.92)(J/ψ 0y|dy

dσ

average)(theory, nb 0.33.0)(J/ψ 0y|dy

dσ

Our limits on O-exchange are close to,and constrain, theoretical predictions


Summary of Results pppp M = 3-4 GeV/c2

(IP)p(γγp TT

No strong evidence for odderon

mike albrow diffraction in high energy collisions cern june09 1 diffraction in high energy...

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