Linear Collider Hitoshi Murayama (Berkeley) EPP2010@SLAC, Jan 31, 2005
Take-home messages We are approaching a new layer of energy scale: something is brewing at TeV-scale Solutions to many deep puzzles hinge on what we find at this energy scale multiple tools needed to get a complete picture
Outline Brief Recap of Science Need for Multiple Tools Dark Field=Cosmic Superconductor Linear Collider
Brief Recap of Science
Energy budget of Universe Stars and galaxies are only ~0.5% Neutrinos are ~0.1 1.5% Rest of ordinary matter (electrons, protons & neutrons) are 4.4% Dark Matter 23% Dark Energy 73% Anti-Matter 0% Dark Field (Higgs) ~1062 %?? stars baryon neutrinos dark matter dark energy
Einstein s Dream Is there an underlying simplicity behind vast phenomena in Nature? Einstein dreamed to come up with a unified description But he failed to unify electromagnetism and gravity (GR)
History of Unification atoms electric magnetic planets apple electromagnetism Quantum mechanics gravity mechanics γ-decay GR Special relativity Quantum ElectroDynamics Weak force Electroweak theory β-decay α-decay String theory? Grand Unification? Strong Force
deeper into the heart of the matter (literally) increase resolution Einstein? My son on Halloween!
resolution=energy Quantum Mechanics: particle=wave low energy higher energy = shorter wavelength = better resolution high energy
a new layer of unification d!/dq 2 (pb/gev 2 ) 10 1 10-1 10-2 10-3 10-4 10-5 HERA ep collider electromagnetism EM weak weak H1 e + p CC 94-00 prelim. ZEUS e + p CC 99-00 prelim. SM e + p CC (CTEQ5D) H1 e + p NC 94-00 prelim. ZEUS e + p NC 99-00 prelim. SM e + p NC (CTEQ5D) Unification of electromagnetic and weak forces electroweak theory Long-term goal since 60s We are finally getting there! If they are unified, what makes them so different? 10-6 10-7 y < 0.9 10 3 10 4 Dark Field! Q 2 (GeV 2 )
accelerators recreate Big Bang neutrinos observatories reconstruct Big Bang quarks Big Bang inflation unification Dark Field string anti-matter Dark Energy CMB B-mode Dark Matter 10!10 sec 1sec 300Kyr CMB
Need for Multiple Tools
Multiple Wavebands in Astronomy
Evidence for Dark Matter visible Radio Galaxies are held together by mass far bigger than all stars combined
Dark Matter is not atoms Yet another tool: cosmic microwave background matter/all atoms=6.03±0.03 Dominant paradigm: Stable heavy particle produced in early Universe (E=mc2!) left-over from near- complete annihilation TeV: the correct temperature to produce them
Telescopes vs Accelerators aim need telescopes accelerators probe deeper better resolution better mirrors, CCD higher energy better image full understanding better exposure multiple probes larger telescopes, more time visible, radio, X-ray, infrared, UV, gamma more powerful beams (luminosity) protons, electrons, neutrinos
Strong Force Back to 1930s atomic nuclei made of protons and neutrons why don t protons repel each other and nuclei disintegrate? a new mysterious strong force binding them together range of the force 0.000001 nanometer need 100 MeV to study Yukawa predicted the force carrier whose mass is 100 MeV in 1933 discovered in 1947 (140 MeV) case closed?
Strong Force It was rather just the beginning Soon proliferation of strongly-interacting particles at protonbased machines mass [MeV/c 2 ] 3500 3000 2500 2000 1500 1000 a big mess! (i.e. fun) 500 0 #! mesons N baryons strange mesons! baryons Lambda baryons " baryons p, n
Obstruction to Cosmology S. Weinberg Gravitation and Cosmology (1972) 15.11 The Very Early Universe If we look back into the first 0.0001 sec of cosmic history, we encounter theoretical problems. At such temperatures copious number of strongly interacting particles will be in a state of continual mutual interaction and cannot reasonably be expected to obey any simple equation of state. There are two extremely different simple models that reflect two divergent views of the nature of the strongly interacting particles. Neither model can be taken seriously.
Electron scattering electron proton scattering experiment looked dumb because electrons don t do the strong force clear roles: electron=probe proton=object found that protons have constituents: quarks
electron positron collider DALI Run=15768 Evt=5906 ALEPH DALI Run=9063 Ev can see quarks and a gluon ~1980 2004 Nobel to Gross, Wilczek, Politzer
Dark Field = cosmic superconductor
Mystery of the weak force Gravity pulls two massive bodies (long-ranged) Electric force repels two like charges (long-ranged) Weak force pulls protons and electrons (shortranged) acts only over 0.000000001 nanometer [need it for the Sun to burn!] We know the energy scale: 0.3 TeV
We are swimming in Dark Field There is something filling our Universe It doesn t disturb gravity or electric force It does disturb weak force and make it shortranged It slows down all elementary particles from speed of light What is it?? gravity E&M weak e t! t L t R tl e L t R e R! L! L! L 1/M e L e R
Cosmic Superconductor In a superconductor, magnetic field gets repelled (Meißner effect), and penetrates only over the penetration length Magnetic field is short-ranged! Imagine a physicist living in a superconductor She finally figured: magnetic field must be long-ranged there must be a mysterious charge-two Dark Field in her Universe But doesn t know what the Dark Field is, nor why it is there Doesn t have enough energy (gap) to break up Cooper pairs That s the stage where we are!
Kick out Dark Field from the vacuum We know the energy scale of the problem: 0.3 TeV pump energy into empty space to kick out whatever makes Dark Field: Higgs boson LHC will find it!!!!!
Better be sure For something this bizarre, we d better make sure Is the particle discovered really the Higgs boson? Is it really responsible for particle masses? Does this have the right properties? Is it really stuck in our Universe? Need detailed measurements for the proof
Post-Higgs Problem We see what is stuck in our universe But we still don t know why Two problems: Why anything is stuck at all Why is the scale of Dark Field 0.3TeV much much smaller than the scale of gravity ~10 15 TeV Explanation most likely to be at TeV scale because this is the relevant energy scale
Three Directions History repeats itself discovery of anti-matter doubled #particles Double #particles again supersymmetry Learn from Cooper pairs Cooper pairs composite made of two electrons Higgs boson may be pairwise composite technicolor Physics as we know it ends at TeV Ultimate scale of physics: quantum gravity May have quantum gravity at TeV hidden dimensions (0.01 cm to 10 17 cm) e e! G
More Directions Higgs boson as a Pseudo-Nambu- Goldstone boson (Little Higgs) Higgs boson as an extra-dimensional gauge boson (Gauge-Higgs Unification) Fat Higgs (Composite) Higgsless and W ± as Kaluza-Klein boson technicolorful supersymmetry
Task Why is there Dark Field? We can eliminate many possibilities at LHC But new interpretations necessarily emerge Race will be on: theorists coming up with new interpretations experimentalists excluding new interpretations A loooong process of elimination Crucial information is in details Reconstruct the theory from measurements
Need absolute confidence for a major discovery As an example, supersymmetry New-York Times level confidence still a long way to Halliday-Resnick level confidence We have learned that all particles we observe have unique partners of different spin and statistics, called superpartners, that make our theory of elementary particles valid to small distances.
accelerators recreate Big Bang neutrinos observatories reconstruct Big Bang quarks Big Bang inflation unification Dark Field string anti-matter Dark Energy CMB B-mode Dark Matter 10!10 sec 1sec 300Kyr CMB
International Linear Collider (ILC)
ILC electron position collider at 0.5-1 TeV about 20 miles long super-high-tech: nanometer beams damping ring positron preaccelerator collision hall positron source aux. positron and 2nd electron source damping ring e - electron sources e - linear accelerator linear accelerator e + 33 km
ILC elementary particles well-defined energy, angular momentum uses its full energy can produce particles democratically LHC p p can capture nearly full information ILC e + e -
ILC superconducting cavities for main accelerator technology is extremely challenging, yet basically at hand world-wide design in development need to complete the design (a real work!)
LHC vs ILC total energy 14TeV 0.5-1 TeV usable energy a fraction full beam proton (composite) electron (point-like) signal rate high low noise rate very high low events lose info along the beams capture the whole status under construction needs to finish design
Take-home messages We are approaching a new layer of energy scale: something is brewing at TeV-scale Solutions to many deep puzzles hinge on what we find at this energy scale multiple tools needed to get a complete picture
In the Next Talk: See how ILC, together with LHC can establish Higgs generates all masses can establish supersymmetry can test unification can figure out what Dark Matter is can study extra dimensions, measure their number, shape, geometry