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
Top Related