Lepton-Photon 2007Summary and Outlook

Young-Kee KimThe University of Chicago and Fermilab

August 18, 2007Daegu, Korea

What is the world made of?What holds the world together?

Where did we come from?

Primitive Thinker

1. Are there undiscovered principles of nature: New symmetries, new physical laws?

2. How can we solve the mystery of dark energy?3. Are there extra dimensions of space?4. Do all the forces become one?5. Why are there so many kinds of particles?6. What is dark matter?

How can we make it in the laboratory?7. What are neutrinos telling us?8. How did the universe come to be?9. What happened to the antimatter?

Evolved Thinker

From “Quantum Universe” and“Discovering Quantum Universe”

Breakthroughs will likely come at Tera scale physics

Laws of Physics in the Early Universe

Higher Energy by Accelerators and other toolsAstrophysical Observations

Accelerators (output of Accelerator Science)are powerful tools for Particle Physics!

PEP-II, SLAC, Palo Alto, USAe-e+ collider

HERA, DESY, Hamburg, Germanye-proton or e+proton collider

KEKb, KEK, Tsukuba, Japane-e+ collider

Tevatron, Fermilab, Chicago, USAproton-antiproton collider

Colliders

Tevatron

PEP II

CESR

LHC

HERA

Proposed ILC

2007 2010 2020

KEK-BBES

DEINERussia?

(Future to be determined)

HERA ended with xxxx (1992 – 2007)

Congratulations!

HERA: 1992 – 2007

Accelerators (excluding colliders)for Neutrino and Precision Physics

JPARC (T2K, Kaon)

NUMI (MINOS, MINERvA, NOvA)

MiniBooNE, SciBooNE

LHCb, neutrino in Europe

K2K

2007 2010 2020

particlesanti-particles

particles

Accelerators

BigBang

Inflation

Create particles that existed ~0.001 ns after Big Bang

Tevatron

E = mc2

top quark

anti-top quark

ZW+, W-

. . . .e e- u d s c b

gluons

Elementary Particles and Masses

e e+ u d s c b- - - - - - - -

(Mass proportional to area shown: = proton mass)

Energy Frontier Accelerators

HERA at DESY320 GeV ep1992 – 2007

Tevatron at Fermilab2 TeV pp-bar1985 – 2009

LHC at CERN14 TeV pp collider

from 2008

International Linear Collider0.5~1 TeV e+e- collider

extending LHC discovery reach

Beyond the ILC and the LHC

• CLIC

• Muon Collider

• Very Large Hadron Collider

Connection: Energy Frontier Acceleratorsmany activities around the world

TevatronHERA

LHC

ILC

Workshops W

orks

hops

Remote Control

Tevatron

CDF - PISA

LHC remote

Origin of Mass:There might be something (new particle?!) in the universe

that gives mass to particles

Nothing in the universe Something in the universeHiggs Particles:Higgs Particles:

xx

x

xxx

x

xx xxx

x

Electron

Z,W Boson

Top Quark

Mass∞

coupling strength to Higgs

mass

Higgs!

Precision Electroweak Measurements

HERA – Charged Current ep Scattering

Tevatron’s Top Quark Discovery

Top Mass Predictionby EWK Meas.s

Top MassDirect Measurements

Higgs Mass Prediction via Quantum Corrections

Mtop (GeV)

MW

(GeV

)

150 175 200

80.5

80.4

80.3

1 GeV = 1 GeV / c2 ~ proton mass

M higgs

= 1

00 G

eV20

0 GeV

300

GeV

500

GeV

1000

GeV

W

top

Higgs

W

bottom

W and Top Mass: from 1998 to 2007

Tevatron + LEP2 … LEP1 + SLD …

80.6

80.5

80.4

80.3

80.2130 150 170 190 210

Top Mass [GeV/c2]

W Mass[GeV/c2]

Higgs mass < ~144 GeV at 95%CL

W

top

Higgs

W

bottom

Tevatron: Improve Higgs Mass Pred. via Quantum CorrectionsLHC: Designed to discover Higgs with Mhiggs = 100 ~ 800 GeV

M (GeV)

130 GeV Higgs

# of

eve

nts

/ 0.

5 G

eV

Will Tevatron’s prediction and possible observation agree with what LHC sees?

Higgs sector may be very complex. New physics models expect multiple Higgs particles.

MHiggs (GeV)5

Dis

cove

ry L

umin

osity

(fb

-1)

hard hard

LHC(CMS)

easy

Mtop (GeV)

MW

(GeV

)

Tevatron:mtop

= 171.4 ± 2.1 GeV!

Tevatron2009

Supersymmetric Extension of Standard Model (SUSY)

e+ e-

superparticle

e e~

e

spin 1/2 spin 0 Me ≠ Me

Symmetry betweenfermions (matter) and bosons (forces)

“Undiscovered new symmetry”

solves SM problems: Higgs Mass, Unification, Dark Matter candidate,Matter-Antimatter Asymmetry, Connection to Dark Energy?

~

LHC will be the greatest placeto discover SUSY Higgs, SUSY particles!

LHC Higgs (BSM)

ILC Higgs

International Collaboration

K2K Near Detector SciBooNE

SciBar detector

SciBarDetector

SciBar detector

Higg

Many SUSY models affect significantly properties of Bs particles.• transition rate from Bs to its anti-particle: ms

• rate of decay to

Tevatron’s first observation of ms: agreeing well with SM(see yesterday’s Chicago Tribune)

Tevatron’s limits on Bs decay rate < 1.0 x 10-7

Already put stringent limits on SUSY models.There is little room left for generic supersymmetry models that

produce large flavor-changing effects.

Direct searches for SUSY particles at Tevatron

Will this agree with future discoveries?

Ruling out some of SUSY models by Tevatron

If we discover a “Higgs-like” particle,is it alone responsible for giving mass to W, Z, fermions?

Experimenters must precisely measurethe properties of the Higgs particle

without invoking theoretical assumptions.

proton anti-proton / proton

e- e+

• elementary particles• well-defined energy and angular momentum• uses its full energy• can capture nearly full information

Tevatron / LHC

ILC:

ILC can observe Higgs no matter how it decays!

100 120 140 160Recoil Mass (GeV)

MHiggs = 120 GeV

Num

ber

of E

vent

s /

1.5

GeV

Only possible at the ILC

ILC simulation for e+e- Z + Higgswith Z 2 b’s, and Higgs invisible

ILC experiments will have the unique ability to make model-independent tests of Higgs couplings to other particles.

This sensitivity is sufficient to discover extra dimensions, SUSY, sources of CP violation, or other novel phenomena.

The Higgs is Different!

All the matter particles are spin-1/2 fermions.All the force carriers are spin-1 bosons.

Higgs particles are spin-0 bosons.The Higgs is neither matter nor force;

The Higgs is just different.This would be the first fundamental scalar ever discovered.

The Higgs field is thought to fill the entire universe.Could give a handle on dark energy(scalar field)?

If discovered, the Higgs is a very powerful probe of new physics.

Hadron collider(s) will discover the Higgs.ILC will use the Higgs as a window viewing the unknown.

HERA

Q2 [GeV2]

Electromagnetic ForceWeak Force

f

HERA:H1 +ZEUS

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Higher energy, Shorter distance

Str

onge

r fo

rce

13 orders of magnitude higher energy

104 108 1012 1016 1020

Q [GeV]

-1

-1

-1

60

40

20

0

-1

The Standard Model fails to unify the strong and electroweak forces.

104 108 1012 1016 1020

Q [GeV]

60

40

20

0

-1

-1

-1

-1

With SUSY

But details count!Precision measurements are crucial.

With SUSYUnifying gravity to the other 3 is accomplished by String theory.

String theory predicts extra hidden dimensions in spacebeyond the three we sense daily.

Can we observe or feel them? too small?

Other models predict large extra dimensions:large enough to observe up to multi TeV scale.

Large Extra Dimensions of Space

LHC can discover partner towers up to a given energy scale. ILC can identify the size, shape and # of extra dimensions.

qq,gg GN e+e-,+-

Mee, [GeV]

LHC

Mee [GeV]

DZero

Tevatron

GNq

q

e+

e-

Tevatron Sensitivity2.4 TeV @95% CL

Collision Energy [GeV]

Graviton disappears into the ED

Pro

duc

tion

Rat

e

ILC

GN

e+

e-

New forces of nature new gauge boson

LHC has great discovery potential for multi TeV Z’.Using polarized e+, e- beams and measuring angular distribution of leptons, ILC

can measure Z’ couplings to leptons, discriminate origins of the new force.

Mee [GeV] M [GeV]

Vec

tor

Cou

plin

g

Axial Coupling

Related to originof masses

Related toorigin of Higgs

Related toExtra dimensions

Tevatron LHC ILC104

103

102

10

1

10-1

Events/2GeV

qq Z’ e+e-

Tevatron sensitivity~1 TeV

CDF Preliminary

Dark Matter in the Laboratory

A common bond between astronomers, astrophysicists and particle physicists

Underground experiments may detect Dark Matter candidates.

Only accelerators can produce dark matter in the laboratory and understand exactly what it is.

LHC may find Dark Matter (a SUSY particle).ILC can determine its properties with extreme detail, to computewhich fraction of the total DM density of the universe it makes.

Particles Tell Stories!

The discovery of a new particle is often the opening chapter revealing unexpected features of our universe.

Particles are messengers telling a profound story

about nature and laws of nature in microscopic world.

The role of physicists is to find the particles and to listen to their stories.

Discovering a new particle is Exciting!

Top quark eventrecorded early 90’s

We are listening to the story that top quarks are telling us:Story is consistent with our understanding of the standard model

so far. But why is the mass so large?We are now searching for a story we have not heard before.

Hoping in the next ~5 years LHC/Tevatron will discover Higgs. ILC will allow us to listen very carefully to Higgs.

This will open windows for discovering new laws of nature.

Discovering “laws of nature” is even more Exciting!!

This saga continues…. There might be supersymmetric partners, dark matter,

another force carrier, large extra dimensions, …… for other new laws of nature.

Whatever is out there, this is our best opportunity to find it’s story!

Precision Physics with quarks

• Tevatron B, C, …

• PEP II, KEK-B

• DEPHINE

• HERMES

• Future– HERA B– Super B?

Neutrinos

• MiniBooNE• SciBooNE• MINOS• MINERvA• NOVA• T2K• DUSEL -- NSF

• Non Accelerator based– CHOOZ– Daya Bay– Korean/

• Double beta decays

• Astrophysical observations

Particle Astrophysics

• Underground Experiment– Dark Matter

• Telescope– Ground-based– Space-based