Lepton-Photon 2007 Summary and Outlook Young-Kee Kim The University of Chicago and Fermilab August 18, 2007 Daegu, 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 tools Astrophysical Observations

Accelerators (output of Accelerator Science) are powerful tools for Particle Physics! PEP-II, SLAC, Palo Alto, USA e - e + collider HERA, DESY, Hamburg, Germany e - proton or e + proton collider KEKb, KEK, Tsukuba, Japan e - e + collider Tevatron, Fermilab, Chicago, USA proton-antiproton collider

Colliders Tevatron PEP II CESR LHC HERA Proposed ILC KEK-B BES DE  INE Russia? (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

particles anti-particles particles Accelerators Big Bang Inflation Create particles that existed ~0.001 ns after Big Bang Tevatron E = mc 2

top quark anti-top quark Z W +, 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 DESY 320 GeV ep 1992 – 2007 Tevatron at Fermilab 2 TeV pp-bar 1985 – 2009 LHC at CERN 14 TeV pp collider from 2008 International Linear Collider 0.5~1 TeV e + e - collider extending LHC discovery reach

Beyond the ILC and the LHC CLIC Muon Collider Very Large Hadron Collider

Connection: Energy Frontier Accelerators many activities around the world Tevatron HERA LHC ILC Workshops

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 universe Higgs Particles: x x x xx x x xx x xx 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 Prediction by EWK Meas.s Top Mass Direct Measurements

Higgs Mass Prediction via Quantum Corrections M top (GeV) M W (GeV) GeV = 1 GeV / c 2 ~ proton mass M higgs = 100 GeV 200 GeV 300 GeV 500 GeV 1000 GeV W top Higgs W bottom

W and Top Mass: from 1998 to 2007 Tevatron + LEP2 … LEP1 + SLD … Top Mass [GeV/c 2 ] W Mass [GeV/c 2 ] Higgs mass < ~144 GeV at 95%CL W top Higgs W bottom

Tevatron: Improve Higgs Mass Pred. via Quantum Corrections LHC: Designed to discover Higgs with M higgs = 100 ~ 800 GeV M  (GeV) 130 GeV Higgs # of events / 0.5 GeV 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. M Higgs (GeV) 5  Discovery Luminosity (fb -1 ) hard LHC (CMS) easy M top (GeV) M W (GeV) Tevatron: m top = ± 2.1 GeV! Tevatron 2009

Supersymmetric Extension of Standard Model (SUSY) e+ e- superparticle e ~ e spin 1/2 spin 0 M e ≠ M e Symmetry between fermions (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 place to discover SUSY Higgs, SUSY particles!

LHC Higgs (BSM)

ILC Higgs

International Collaboration K2K Near DetectorSciBooNE SciBar detector SciBar Detector SciBar detector

Higg

Many SUSY models affect significantly properties of B s particles. transition rate from B s to its anti-particle:  m s rate of decay to  Tevatron’s first observation of  m s : agreeing well with SM (see yesterday’s Chicago Tribune) Tevatron’s limits on B s   decay rate < 1.0 x 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 measure the 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! Recoil Mass (GeV) M Higgs = 120 GeV Number of Events / 1.5 GeV Only possible at the ILC ILC simulation for e + e -  Z + Higgs with 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 Q 2 [GeV 2 ] Electromagnetic Force Weak Force f  HERA: H1 + ZEUS Higher energy, Shorter distance Stronger force

13 orders of magnitude higher energy Q [GeV]   -1   -1    -1 The Standard Model fails to unify the strong and electroweak forces.

Q [GeV]  -1   -1   -1   -1 With SUSY But details count! Precision measurements are crucial.

With SUSY Unifying gravity to the other 3 is accomplished by String theory. String theory predicts extra hidden dimensions in space beyond 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  G N  e + e -,  +  - M ee,  [GeV] LHC M ee [GeV] DZero Tevatron GNGN qqqq e+e-e+e- Tevatron Sensitivity 2.4 CL Collision Energy [GeV] Graviton disappears into the ED Production Rate ILC GNGN e+e-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. M ee [GeV] M  [GeV] Vector Coupling Axial Coupling Related to origin of  masses Related to origin of Higgs Related to Extra dimensions Tevatron LHC ILC 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 compute which 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 event recorded 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