Conference Summary

ICHEP 2004, BeijingJohn Ellis

CERN

The Basis of Particle Physics

String theory

Cosmology

Future accelerators

Barbieri

@ HERA

Klein

CrucialFor LHC

QCD Works!

@ Tevatron

b production

Lucchesi

World Summary of αS(MZ) – July 2004

world average (MSbar, NNLO)

αS(MZ) = 0.1182 0.0027

cf. (2002) 0.1183 0.0027

Bethke , hep-ex/0407021

Stirling

NNLO pQCDCalculations

Parton splitting functions

W, Z cross sections

+ 7 pages! Moch, Vermaseren & Vogt

jetson

way

Stirling

QCD Calculations in String Approach

• Maximal helicity-violating (MHV) amplitudes as effective vertices in a new scalar graph approach

• use them with scalar propagators to calculate

– tree-level non-MHV amplitudes

– with both quarks and gluons

– … and loop diagrams!

• dramatic simplification: compact output in terms of familiar spinor products

• phenomenology? multijet cross sections at LHC, etc. underway

Cachazo, Svrcek & Witten

Stirling

QCD phase diagram

Hadron gas

Dunlop

Particle Production Ratios

Well described by simple thermodynamic model, T ~ lattice …

… but could these just be phase space and statistics?

Dunlop

Elliptic Flow: the Shape of the Interaction Region at RHIC

Anisotropic Flow

x

yz

Peripheral Collisions

Reproduced well by hydrodynamic model

Shape parameter v2

but hydrodynamic model failsto reproduce HBT source size

Dunlop

Hadron Elliptic Flows Scale with Quark Number

)3/p( v3 ~)p( vand )2/p( v2 ~)p( vpions,Except T2,qTB2,T2,qTM2,

Dunlop

Jet Quenching @ RHIC …

… due to parton energy loss in QGP?

Dunlop

The State of Heavy-Ion Theory

• A patchwork, with model parameters adjusted independently for different observables.

• Statistical equilibriation or phase space?• Hydrodynamical model: EOS vs realistic quark-gluon

calculations?• Source size as measured by HBT?• Parton energy loss: promising development!• Watch out for J/ψ suppression!• For compelling QGP claim, need quantitative

estimates of theoretical uncertainties

Dunlop

Questions on Hadron Spectroscopy

• Do (which) pentaquarks exist?• Do other exotic hadrons exist?• What are the quark descriptions of the

DsJ(2317) and DsJ(2460)?• Does the DsJ(2632) exist (SELEX)?• What is the quark description of the X(3872)?• Interpretation of threshold reported states?• Fate of 12% rule in ψ’ decay (BES)?

Some Sightings of the Θ+(1530) …

… but many negative searches

Jin

Summary of Positive Results

(LEPS)

nK

Inconsistencies in Mθ and Γθ?

0SpK

Also width of θ+(1540)

- Two “positive” experiments:

HERMES: Γθ = 17 9 2 MeV

ZEUS: Γθ = 8 4 MeV

K+N PWA indicates Γθ < 1 MeV

Jin

M(nK+)≠ M(pKs)?

Summary of Negative Results

How Significant are Negative Results?

• Compare with production of other baryons resonances

• Λ(1520) may not be most reliable guide

• Most positive results at lower energies

• Different production mechanisms for exotic baryons?

Jin

Interpretations of θ+(1530) – if it exists

• Naïve non-relativistic quark model would need epicycles:

di/triquarks, P-wave ground state• Predicted in chiral soliton model:

fits data, predicts other exotic states• Existence requires confirmation:

a high-statistics, -significance experiment• If it exists, θ+ spin & parity distinguish models

The stakes are high: the θ+(Ξ , θc) may take us beyond the naïve quark model

← Based on idea thatquarks weigh << ΛQCD

Close

X(3872 ): Charmonium or D0D*0 “Molecular State”?

’J/

X(3872) 10σeffect

Belle, also CDF, D0

MeV

MeVM

3.2

5.06.00.3872at 90% C.L.

No D0D0 → unnatural spin-parity

Jin

M()

BK X(3872)

Belle

Also reported in ωJ/ψ:mixed isospin would

→ mixing with D0D*0 molecule Close

M=1859 MeV/c2

< 30 MeV/c2 (90% CL)

J/pp

M(pp)-2mp (GeV)

0 0.1 0.2 0.3

3-body phase space acceptance

2/dof=56/56

acceptance weighted BW +3 +5

10 25

BES IIalso pΛ,pΛc, KΛ,

ππ,πΚ

Hadronic Threshold States

Quark description inadequate: need hadronic description? molecules, …?

Jin

Electroweak Physics

APV, E158compatible

with expectedrunning of α(Q2)

NuTeV:EW corrections - 1σ?

Strange sea - 1σ?ubar ≠ dbar - 1σ?

(NOMAD)

Teubert

Low Energy vs High Energy

Top-Quark Mass: Run 1 Revisited

D0: improved Run 1 value

) GeV 5.1 174.3 m (previous t

t tM M 2.4 %

t

m 178.0 2.7(stat) 3.3

New world average (Run 1 on

(syst) GeV

178.0 4.3 GeV

ly):

new

Implications for fit to Higgs mass …

Denisov

FutureTevatronProspects

The Blue Band PlotGlobal electroweak fit – high Q2 data

Since Aachen EPS Summer 2003:

new top mass increases mH

by ~20 GeV

new 2-loop terms etc. increase mH by ~6 GeV

t

S Z

+ 69H - 4

2

5

H

m = 178.2 3.9 GeV

(M ) = 0.1186 0.0027

m = 114

= 15.8/13 df (prob = 2

GeV

m < 260 GeV (

6

95 )

%)

% cl

(5)had Z Hfor (M ) = 0.02749 0.00012 m 129 GeV

2W H

from uncertainties of 2 (& leading 3)

loops for M & sin (main ef

'bl

fec

ueb

t f

and'

or m )eff

new

Teubert

BES et al

Pulls on Global Fit

Direct search limit

Higgs mass from individual measurements

How Good is the Global Electroweak Fit?

Heavy flavours ≠ leptons, mW

Teubert

Denisov, Barr //

fb-1

1 year @1033

1 month @1033

1 year @1034

LHC: ATLAS

Values for single experiment

h → requiresexcellent low-pT lepton + tau jet trigger

tim

e

Looking for Standard-Model Higgs

Flavour Physics: Some Questions

• Are the data on quark mixing described by the CKM model?

• Are there signatures of physics beyond the SM?

• If not, why is new physics flavour-blind?• Why is neutrino mixing so different from

quark mixing?• Can they be related?

Sakai, Ali, Giorgi, Ligeti, Patera, Shipsey, Langacker, McGrew, Wang

New Determinations of Vus

CKM unitarity ‘crisis’ has disappeared

Vu

s x f

+(0

)

•PDG02

Patera

Global CKM FitSakai,Ali,

Giorgi,Ligeti

Matrix elements from lattice: Hashimoto

φK0 has moved towards SM

η’ Ks at 2.6 from sin2[cc]

<s-penguins> at 3.5 from sin2[cc]

BUT: expect corrections to sin2[cc] for many modes

Compare sin2 & s-Penguin Results

Sakai,Ali,

Giorgi,Ligeti

Measuring α with B→ ππ, ρπ and ρρ Decays

Excellent agreement with global CKM fit

100

+ 12- 10

CP Violation in B0 → K+ π-

Discrepancy withACP(K+π0 ) = 0.04 0.05 0.02 ?Electroweak penguins? NP? Final-state interactions?

First evidence for direct CPV in B decays

Sakai,Ali,

Giorgi,Ligeti

Putting all the Information Together

Is there room for NP?

Sakai, Ali, Giorgi, Ligeti

Still Room for Future ProgressLigeti

Rare KDecays

KL→0e+e-

KL→0+-

KS→0e+e-

KS→0+-

KL→0

Im t = A23

)0,1()0,0(

),(

The connection of the KL0e+e-() decays to t

needs work on ancillary modes

More handles on triangle

Results & prospectsfor K+ → π+νν

Bounds & prospectsfor KL

→ π0νν

KS → π0l +l-, π0γγimportant forKL → π0l +l-

Patera

Neutrino Masses & Oscillations• First confirmed physics beyond SM• LSND? Waiting for MiniBooNE• (Near) bimaximal mixing ≠ quarks:

Is there a relation: θν+θc = π/4? Reactors for θ13? • Dirac or Majorana masses: seesaw?

Normal or inverted hierarchy? ββ0ν?

• Holy Grail: CP violation via phase δ?Indirect relation to cosmology via

baryogenesis?

• Search for violation of charged lepton numbers

Langacker

L/E Significance

The dips in the data cannot be explained by other models

Δχ2 (neutrino decay – oscillation) =11.4 3.4 σ

Δχ2 (neutrino decoherence – osc’n)

=14.6 3.8 σ

Evidence for Neutrino Oscillation Patternfrom Super-Kamiokande & KamLAND

Oscillation

Decay

Decoherence

Wang

KamLAND

SK/SNO

sin2 is determined by SK/SNO

KamLAND consistent with SK/SNO

Wang

K2K confirms Super-Kamiokande

K2K Rate suppression and

spectral distortion …

… agree with SK azimuthal distributionsand

L/E analysis

McGrew, Wang

Physics beyond the SM

• The most pressing issue is breaking EW symmetry

• Must be solved below 1 TeV energy• Would be a revolution in fundamental physics• Basis for any further theoretical speculations• Hints of grand unification: gauge couplings,

neutrino masses, but wait and see• String unification is still the dream

Barbieri

Breaking Electroweak Symmetry• Calculability principle:

EW scale should be calculable in terms of other mass scale

• No quadratic divergences: supersymmetry ?

or Higgs as pseudo-Goldstone boson ?

• Supersymmetry: also gauge unification and dark matter

• LEP data: some fine-tuning needed

Barbieri

Alternatives to Supersymmetry

• Interpretation of EW data?consistency of measurements? Discard some?

• Higgs + higher-dimensional operators?corridors to higher Higgs masses?

• Little Higgs modelsextra `Top’, gauge bosons, `Higgses’

• Higgsless modelsstrong WW scattering, extra D?

Barbieri

Little Higgs Models

• Embed SM in larger gauge group• Higgs as pseudo-Goldstone boson• Cancel top loop

with new heavy T quark

• New gauge bosons, Higgses• Higgs light, other new

physics heavyNot as complete as susy: more physics > 10 TeV

MT < 2 TeV (mh / 200 GeV)2

MW’ < 6 TeV (mh / 200 GeV)2

MH++ < 10 TeV

zoomzoom

gμ - 2: e+e- Data vs τ Data

KLOE agrees with CMD-2: discard τ dataWhy the 10%

τ - e+e- discrepancy above ρ peak?

Largest contributions, errors from low energies

Teubert

Updated Results for gμ - 2(693.4 ± 5.3 ± 3.5) 10 –10=

(11 659 182.8 ± 6.3had ± 3.5LBL ± 0.3QED+EW) 10 –10=a SM

[e+e– ]

ahad [e+e– ]

Weak contribution : aweak = + (15.4 ± 0.3) 10 –10

Hadronic contribution from higher order : ahad [( /)3] = – (10.0 ± 0.6) 10 –10

Hadronic contribution from LBL scattering: ahad [LBL] = + (12.0 ± 3.5) 10 –10

2.7 standard deviations

=(25.2 ± 9.2) 10 –10a

exp – a SM

not yet published

not yet published

preliminary

BNL E821 (2004):aexp = (11 659 208.0 5.8) 1010

Teubert

Squark & Gluino Searches @ FNAL

GeneralSquarks

& gluinos

Specificsearch

for lightsbottom

Heinemann

Sparticle mass measurements @ LHC

• Mass measurements from exclusive cascade decays

• Mass differences well measured– Typically limited by

detector performance• Of order 1%

• Error in overall mass scale– Unknown missing energy

• Of order 10%

ATLASSquark – neutralino1mass difference5 fb-1

q

qR

~

qR

~q

p p

Barr //

l+

l- parton-level

-> Measure spin-1/2 nature of neutralino-2-> Also can measure scalar nature of slepton-> Success at several distinct points in parameter space

detector-level

Lepton+jet invariant massC

har

ge a

sym

met

ry

spin-0

Eve

nts

Measuring Sparticle Spin @ LHC

0* 1*

ATLAS

ATLAS

Barr //

NLO QCD Calculations Needed for Extracting BSM signals

Stirling

Road Map for EWSB Physics

Barbieri

A Few Remarks on String Theory

• A very powerful tool, e.g., for QCD• Already solved many problems in Q. Gravity• Is it relevant to particle physics?• Can string theory explain the origin of the

Universe?• Could it replace inflation by a scalar field?• What is the landscape of string vacua?• Distinctive experimental signature: extra D?

Liu

Stirling

Particle Astrophysics and Cosmology

• What is the Dark Matter?• Is there Dark Energy?• Are there Ultra-High-Energy Cosmic

Rays beyond the GZK cutoff?• Was there inflation?• How did the Universe begin?

Binetruy

Composition of the Cosmos

WIMPs

WMAP best fit

Binetruy

Concordance Cosmological Model

WMAP+SN+HST

WMAP, Supernovae,Large-scale structures …

Barbiellini //, Ghirlanda et al

… and gamma-ray bursters?

Candidates for Cold Dark Matter

• Axion?• Lightest Supersymmetric Particle (LSP)?

neutralino? gravitino?accelerators vs non-accelerator expts?

• Lightest Kaluza-Klein Particle (LKP)?in models with universal extra

dimensions• Superheavy (metastable) Particle?

‘WIMPzilla’ produced at inflation?decays responsible for UHECRs??

Direct Search for Dark Matter

- Look for elastic scatteringon nuclei in low-backgroundexperiment

- DAMA modulation signaldifficult to reconcile withother experiments, such asCDMS2

- Good prospects forimprovement by factor ~ 20

- Starting to reach regionexpected in models

Binetruy

~2 degrees around the galactic center

EGRET data

Annihilation channel W+W-

Mχ =80.3 GeV

background model(Galprop)WIMP annihilation (DarkSusy)Total

Contribution

Gamma Rays from Neutralino Annihilations?

- Uncertainties incosmic-ray bkgrd- Also in signalnormalization

Morselli, Sander //

Neutralino Annihilations inside Sun?

Look forχχ→ν→μ

Future

Present

Questions on Future Accelerators

• What do we want?• How can we involve a diversity of regions?• How can we ensure diversity of facilities?• Can we work together to get them approved?• Can we build them?• Can we do experiments with them?• Will they answer all our questions?• How can we ensure access to them? Lüth

Brau

Yokoya

Dorfan

Miller

Barbieri

Motivations for Future Colliders

• Physics AND cosmology make us expect strong new signals at the scale of 1 TeV

• Physics case for LHC has been made and accepted:

It will look into the whole region where new physics should be

• Physics case for the TeV ILC has been made.• Physics cases for CLIC (and Larger HC?) will

follow results from LHC (and TeV ILC)

Miller

Tasks for the TeV ILC

• Measure mt to < 100 MeV

• If there is a light Higgs of any kind, pin it down:

Does it have standard model couplings? What is its precise mass?

• If there are extra light particles: Measure mass and

properties

• If LHC sees nothing new below ~ 500 GeV:

Look for indirect signatures

Miller

Examples of Possible Indirect Physics

- (e+e- f f )(direct)

ILC

Sensitivities to a Z’ Parameters of a WLWL Resonance

Imposing a1=1 (SM coupling) get blue bar from LHC, red from ILC.

LHC fit,100fb-1

LC 1 TeV 1 ab-1

Miller

The ITRP Recommendation• We recommend that the linear collider be based on superconducting rf

technology (from Exec. Summary)

– This recommendation is made with the understanding that we are recommending a technology, not a design. We expect the final design to be developed by a team drawn from the combined warm and cold linear collider communities, taking full advantage of the experience and expertise of both (from the Executive Summary).

– We submit the Executive Summary today to ILCSC & ICFA

– Details of the assessment will be presented in the body of the ITRP report to be published around mid September

– The superconducting technology has features that tipped the balance in its favor. They follow in part from the low rf frequency.

Dorfan

Beyond the TeV ILC

• We need 2 LCs:The TeV ILC, asap, then a multi- (~3?) TeV CLIC

The CLIC two-beam accelerator concept The third CLIC test facility

Plan to demonstrate R1, R2 BY 2009: Δt ~ 5y relative to ILCYokoya

Miller

Sparticles may not be very light

FullModel

samples

Detectable@ LHC

ProvideDark Matter

Dark MatterDetectable

Directly

Lightest visible sparticle →

← S

econd lightest visible sparticle

JE, Olive, Santoso, Spanos

Summary of the Summary

• QCD ever more quantitative• Electroweak theory suggests new physics @ TeV

scale: Higgs + ?• Flavour physics becoming quantitative• CKM looking better and better• Neutrinos really do oscillate!• Growing symbiosis with cosmology• LHC on its way• Good ideas for future accelerators• ITRP has done its work

Lets get back to our work!