-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
The Major Problems in Particle Physicsand How We Hope to Address Them
• The standard model
• Testing the standard model
• Problems
• Beyond the standard model
• Where are we going?
NYS APS (October 15, 2004) Paul Langacker (Penn)
Weak Interactions and Neutrinos in the LHC Era
• The standard model
• Testing the standard model
• Problems
• Beyond the standard model
• Where are we going?
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Many special features usually not maintained in BSM– mν = 0 in old standard model (need to add singlet fermion and/or
triplet Higgs and/or higher dimensional operator (HDO))
– Yukawa coupling h ∝ gm/MW ⇒ flavor conserving and smallfor light fermions (partially maintained in MSSM and simple 2HDM)
– No FCNC at tree level (Z or h); suppressed at loop level(SUSY loops; Z′ from strings, DSB)
– Suppressed off-diagonal #CP ; highly suppressed diagonal (EDMs)(SUSY loops, soft parameters, exotics)
– B, L conserved perturbatively (B − L non-perturbatively)(GUT (string) interactions, "Rp)
– New TeV scale interactions suggested by top-down(Z′, exotics, extended Higgs)
Physics at LHC (July 16, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Quantum Chromodynamics (QCD)
Modern theory of the strong interactions
NYS APS (October 15, 2004) Paul Langacker (Penn)
10 16. Structure functions
Table 16.1: Lepton-nucleon and related hard-scattering processes and theirprimary sensitivity to the parton distributions that are probed.
Main PDFsProcess Subprocess Probed
!±N → !±X γ∗q → q g(x 0.01), q, q!+(!−)N → ν(ν)X W ∗q → q′ν(ν)N → !−(!+)X W ∗q → q′ν N → µ+µ−X W ∗s → c → µ+ spp → γX qg → γq g(x ∼ 0.4)pN → µ+µ−X qq → γ∗ qpp, pn → µ+µ−X uu, dd → γ∗ u − d
ud, du → γ∗ep, en → eπX γ∗q → qpp → W → !±X ud → W u, d, u/dpp → jet +X gg, qg, qq → 2j q, g(0.01 x 0.5)
all polarized PDFs. These polarized PDFs may be fully accessed via flavor tagging insemi-inclusive deep inelastic scattering. Fig. 16.5 shows several global analyses at a scaleof 2.5 GeV2 along with the data from semi-inclusive DIS.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
x
x f
(x)
Figure 16.4: Distributions of x times the unpolarized parton distributions f(x)(where f = uv, dv, u, d, s, c, g) using the MRST2001 parameterization [29,13](withuncertainties for uv, dv, and g) at a scale µ2 = 10 GeV2.
June 16, 2004 14:04
Quantum Chromodynamics (QCD)
Modern theory of the strong interactions
• Quark model/ color/confinement
• Low energy symmetries(+ realization, breaking)(SU(3)L×SU(3)R)
• Hadronic models: Yukawa,Regge, dual resonance (→strings)
• Asymptotic freedom (weakcoupling at high energy)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
9. Quantum chromodynamics 7
0.1 0.12 0.14
Average
Hadronic Jets
Polarized DIS
Deep Inelastic Scattering (DIS)
! decays
Z width
Fragmentation
Spectroscopy (Lattice)
ep event shapes
Photo-production
" decay
e+e
- rates
#s(MZ)
Figure 9.1: Summary of the value of αs(MZ) from various processes. The valuesshown indicate the process and the measured value of αs extrapolated to µ = MZ .The error shown is the total error including theoretical uncertainties. The averagequoted in this report which comes from these measurements is also shown. See textfor discussion of errors.
extracted [44,45] are consistent with the theoretical estimates. If the nonperturbativeterms are omitted from the fit, the extracted value of αs(mτ ) decreases by ∼ 0.02.
For αs(mτ ) = 0.35 the perturbative series for Rτ is Rτ ∼ 3.058(1+0.112+0.064+0.036).The size (estimated error) of the nonperturbative term is 20% (7%) of the size of theorder α3s term. The perturbation series is not very well convergent; if the order α3s termis omitted, the extracted value of αs(mτ ) increases by 0.05. The order α4s term has beenestimated [46] and attempts made to resum the entire series [47,48]. These estimates canbe used to obtain an estimate of the errors due to these unknown terms [49,50]. Weassign an uncertainty of ±0.02 to αs(mτ ) from these sources.
Rτ can be extracted from the semi-leptonic branching ratio from the relationRτ = 1/(B(τ → eνν) − 1.97256); where B(τ → eνν) is measured directly or extractedfrom the lifetime, the muon mass, and the muon lifetime assuming universality of leptoncouplings. Using the average lifetime of 290.6 ± 1.1 fs and a τ mass of 1776.99 ± 0.29
September 8, 2004 15:07
9. Quantum chromodynamics 17
required, for example, to facilitate the extraction of CKM elements from measurementsof charm and bottom decay rates. See Ref. 169 for a recent review.
0
0.1
0.2
0.3
1 10 102
µ GeV
!s(µ
)
Figure 9.2: Summary of the values of αs(µ) at the values of µ where they aremeasured. The lines show the central values and the ±1σ limits of our average.The figure clearly shows the decrease in αs(µ) with increasing µ. The data are,in increasing order of µ, τ width, Υ decays, deep inelastic scattering, e+e− eventshapes at 22 GeV from the JADE data, shapes at TRISTAN at 58 GeV, Z width,and e+e− event shapes at 135 and 189 GeV.
9.13. Conclusions
The need for brevity has meant that many other important topics in QCDphenomenology have had to be omitted from this review. One should mention inparticular the study of exclusive processes (form factors, elastic scattering, . . .), thebehavior of quarks and gluons in nuclei, the spin properties of the theory, and QCDeffects in hadron spectroscopy.
We have focused on those high-energy processes which currently offer the mostquantitative tests of perturbative QCD. Figure 9.1 shows the values of αs(MZ) deduced
September 8, 2004 15:07
• Quark model/ color
• Low energy symmetries(+ realization, breaking)(SU(3)L×SU(3)R)
• Hadronic models: Yukawa,Regge, dual resonance (→strings)
• Asymptotic freedom (weakcoupling at low energy)
Relation of “running” αs at different scales
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Quantum Electrodynamics
Experiment Value of α−1 Difference from α−1(ae)Deviation from gyromagnetic 137.035 999 58 (52) [3.8 × 10−9] –
ratio, ae = (g − 2)/2 for e−ac Josephson effect 137.035 988 0 (51) [3.7 × 10−8] (0.116 ± 0.051) × 10−4h/mn (mn is the neutron mass) 137.036 011 9 (51) [3.7 × 10−8] (−0.123 ± 0.051) × 10−4
from n beam
Hyperfine structure in 137.035 993 2 (83) [6.0 × 10−8] (0.064 ± 0.083) × 10−4muonium, µ+e−
Cesium D1 line 137.035 992 4 (41) [3.0 × 10−8] (0.072 ± 0.041) × 10−4
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
Quantum Electrodynamics
Experiment Value of α−1 Difference from α−1(ae)Deviation from gyromagnetic 137.035 999 58 (52) [3.8 × 10−9] –
ratio, ae = (g − 2)/2 for e−ac Josephson effect 137.035 988 0 (51) [3.7 × 10−8] (0.116 ± 0.051) × 10−4h/mn (mn is the neutron mass) 137.036 011 9 (51) [3.7 × 10−8] (−0.123 ± 0.051) × 10−4
from n beam
Hyperfine structure in 137.035 993 2 (83) [6.0 × 10−8] (0.064 ± 0.083) × 10−4muonium, µ+e−
Cesium D1 line 137.035 992 4 (41) [3.0 × 10−8] (0.072 ± 0.041) × 10−4
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
The Electroweak Theory
• QED and weak charged currentunified
• Weak neutral current predicted
• Stringent tests of wnc, Z-poleand beyond
• Fermion gauge and gauge selfinteractions
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
10-2
10-1
1
10
75 100 125 150 175
LEP combined: e+e! " hadrons(#)
$s%
[GeV]
&hadro
n [n
b]
LEP1 $s%
´/%s%
> 0.10LEP2 $s
%´/%s%
> 0.10LEP2 $s
%´/%s%
> 0.85
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Measurement Fit |Omeas−Ofit|/σmeas0 1 2 3
0 1 2 3
Δαhad(mZ)Δα(5) 0.02761 ± 0.00036 0.02768
mZ [GeV]mZ [GeV] 91.1875 ± 0.0021 91.1873ΓZ [GeV]ΓZ [GeV] 2.4952 ± 0.0023 2.4965σhad [nb]σ
0 41.540 ± 0.037 41.481RlRl 20.767 ± 0.025 20.739AfbA
0,l 0.01714 ± 0.00095 0.01642Al(Pτ)Al(Pτ) 0.1465 ± 0.0032 0.1480RbRb 0.21638 ± 0.00066 0.21566RcRc 0.1720 ± 0.0030 0.1723AfbA
0,b 0.0997 ± 0.0016 0.1037AfbA
0,c 0.0706 ± 0.0035 0.0742AbAb 0.925 ± 0.020 0.935AcAc 0.670 ± 0.026 0.668Al(SLD)Al(SLD) 0.1513 ± 0.0021 0.1480sin2θeffsin
2θlept(Qfb) 0.2324 ± 0.0012 0.2314mW [GeV]mW [GeV] 80.425 ± 0.034 80.398ΓW [GeV]ΓW [GeV] 2.133 ± 0.069 2.094mt [GeV]mt [GeV] 178.0 ± 4.3 178.1
Winter 2004
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
0
1
2
3
4
5
6
10020 400mH [GeV]
Δχ2
Excluded Preliminary
Δαhad =Δα(5)
0.02761±0.000360.02747±0.00012incl. low Q2 data
Theory uncertainty• SM correct and unique to zeroth
approx. (gauge principle, group,representations)
• SM correct at loop level (renormgauge theory; mt, αs, MH)
• TeV physics severely constrained(unification vs compositeness)
• Consistent with light elementaryHiggs
• Precise gauge couplings (gaugeunification)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
-1.5
-1
-0.5
0
0.5
1
1.5
-1 -0.5 0 0.5 1 1.5 2
sin 2β
B → ρρ
B → ρρ
Δmd
Δms & Δmd
εK
εK
|Vub/Vcb|
sin 2β
α
βγ
ρ
η
excluded area has CL < 0.05
C K Mf i t t e r
Winter 2004
• Heavy B decays and CPviolation
– CKM (quark mixing) →CP breaking
– Unitarity triangle
– Search for new physics
– Anomalies in electroweakpenguins?
– Baryogenesis?
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Problems with the Standard Model
Lagrangian after symmetry breaking:
L = Lgauge + LHiggs +∑
i
ψ̄i
(i !∂ − mi − miH
ν
)ψi
− g2√
2
(JµW W
−µ + J
µ†W W
+µ
)− eJµQAµ −
g
2 cos θWJµZZµ
Standard model: SU(2)×U(1) (extended to include ν masses) +QCD + general relativity
Mathematically consistent, renormalizable theory
Correct to 10−16 cm
Physics at LHC (July 16, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
However, too much arbitrariness and fine-tuning: O(27) parameters(+ 2 for Majorana ν) and electric charges
• Gauge Problem– complicated gauge group with 3 couplings
– charge quantization (|qe| = |qp|) unexplained– Possible solutions: strings; grand unification; magnetic
monopoles (partial); anomaly constraints (partial)
• Fermion problem– Fermion masses, mixings, families unexplained– Neutrino masses, nature? Probe of Planck/GUT scale?– CP violation inadequate to explain baryon asymmetry– Possible solutions: strings; brane worlds; family symmetries;
compositeness; radiative hierarchies. New sources of CPviolation.
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Higgs/hierarchy problem– Expect M2H = O(M
2W )
– higher order corrections:δM2H/M
2W ∼ 1034
Possible solutions: supersymmetry; dynamical symmetry breaking;large extra dimensions; Little Higgs; anthropically motivated fine-tuning (split supersymmetry) (landscape)
• Strong CP problem– Can add θ32π2g
2sF F̃ to QCD (breaks, P, T, CP)
– dN ⇒ θ < 10−9, but δθ|weak ∼ 10−3– Possible solutions: spontaneously broken global U(1) (Peccei-
Quinn) ⇒ axion; unbroken global U(1) (massless u quark);spontaneously broken CP + other symmetries
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Graviton problem– gravity not unified
– quantum gravity not renormalizable
– cosmological constant: ΛSSB = 8πGN〈V 〉 > 1050Λobs (10124for GUTs, strings)
– Possible solutions:∗ supergravity and Kaluza Klein unify∗ strings yield finite gravity.∗ Λ? Anthropically motivated fine-tuning (landscape)?
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Necessary new ingredients– Mechanism for small neutrino masses
∗ Planck/GUT scale?– Mechanism for baryon asymmetry?
∗ Electroweak transition (Z′ or extended Higgs?)∗ Heavy Majorana neutrino decay (seesaw)?∗ Decay of coherent field? CPT violation?
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
– What is the dark energy?
∗ Cosmological Constant? Quintessence?∗ Related to inflation? Time variation of couplings?
– What is the dark matter?
∗ Lightest supersymmetric particle? Axion?– Suppression of flavor changing neutral currents? Proton decay?
Electric dipole moments?∗ Automatic in standard model, but not in extensions
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Beyond the Standard Model
• The Whimper: A new layer at the TeV scale
• The Hybrid: low fundamental scale/large extra dimensions
• The Bang: unification at the Planck scale, MP = G−1/2N ∼ 1019GeV
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
TypicalModel scale (GeV) MotivationNew W s, Zs, fermions, Higgs 102–1019 Remnant of something else
Family symmetry 102–1019 Fermion (No compelling models)
Composite fermions 102–1019 Fermion (No compelling models)Composite Higgs 103–104 Higgs (No compelling models)Composite W , Z (G, γ?) 103–104 Higgs (No compelling models)Little Higgs 103–104 Higgs
Large extra dimensions (d > 4) 103–106 Higgs, graviton
New global symmetry 108–1012 Strong CP
Kaluza–Klein 1019 GravitonHiggs (0) ⇔ gauge (1) ⇔
Graviton (2) (d > 4)
Grand unification 1014–1019 GaugeStrong ⇔ electroweak
Supersymmetry/supergravity 102–1019 Higgs, gravitonFermion ⇔ boson
Superstrings 1019 All problems!?Strong ⇔ electroweak ⇔
gravityFermion ⇔ boson (d > 4)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Compositeness
• Onion-like layers
• Composite fermions, scalars (dynamical sym. breaking)
• Not like to atom → nucleus +e− → p + n → quark
• Other new TeV layer: Little Higgs
• At most one more layer accessible (Tevatron, LHC, ILC)
• Rare decays (e.g., K → µe)
• Typically, few % effects at LEP/SLC, WNC (challenge for models)
• anomalous V V V , new particles, future WW → WW , FCNC,EDM
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Large extra dimensions (deconstruction, brane worlds)
• Can be motivated by strings, butnew dimensions much larger thanM−1P ∼ 10−33 cm
• Fundamental scale MF ∼1 − 100 TeV # M̄P l =1/
√8πGN ∼ 2.4 × 1018 GeV
– Assume δ extra dimensionswith volume Vδ & M−δF
M̄2P l = M2+δF Vδ & M2F
(Introduces new hierarchy problem)
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Black holes, graviton emission atcolliders!
• Macroscopic gravity effects
• Astrophysics
NYS APS (October 15, 2004) Paul Langacker (Penn)
Particle Physics Probes Of Extra Spacetime Dimensions 29
Figure 7: 95% confidence level upper limits on the strength α (relative to Newtonian gravity)as a function of the range λ of additional Yukawa interactions. The region excluded by previousexperiments (55,56,61) lies above the curves labeled Irvine, Moscow and Lamoreaux, respectively.The most recent results (60) correspond to the curves labeled Eöt-Wash. The heavy dashed line isthe result from Ref. (60), the heavy solid line shows the most recent analysis that uses the totaldata sample.
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Unification
• Unification of interactions
• Grand desert to unification (GUT) or Planck scale
• Elementary Higgs, supersymmetry (SUSY), GUTs, strings
• Possibility of probing to MP and very early universe
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Supersymmetry
• Fermion ↔ boson symmetry
• Motivations– stabilize weak scale ⇒ MSUSY < O(1 TeV) (but recent high scale
ideas)
– supergravity (gauged supersymmetry): unification of gravity(non-renormalizable)
– coupling constants in supersymmetric grand unification
– decoupling of heavy particles (precision)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Consequences– additional charged and neutral
Higgs particles
– M2H0 < cos2 2βM2Z+ H.O.T.
(O(m4t)) < (150 GeV)2,
consistent with LEP
∗ cf., standard model: MH0 <1000 GeV
NYS APS (October 15, 2004) Paul Langacker (Penn)
100 120 140 160 180 200mt [GeV]
10
20
50
100
200
500
1000
MH [
GeV
]
ΓZ, σhad, Rl, Rqasymmetriesν scatteringMWmt
excl
uded
all data90% CL
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Superpartners– q ⇒ q̃, scalar quark– ! ⇒ !̃, scalar lepton– W ⇒ w̃, wino– typical scale: several hundred
GeV
– LSP: cold dark mattercandidate
– SUSY breaking ⇔ large mt– May be large FCNC, EDM,
∆(gµ − 2)
NYS APS (October 15, 2004) Paul Langacker (Penn)
0
100
200
300
400
500
600
700
800
m [GeV]
l̃R
l̃Lν̃l
τ̃1
τ̃2
χ̃01
χ̃02
χ̃03
χ̃04
χ̃±1
χ̃±2
ũL, d̃RũR, d̃L
g̃
t̃1
t̃2
b̃1
b̃2
h0
H0, A0 H±
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Grand Unification
• Unify strong SU(3) andelectroweak SU(2)×U(1)in simple group, broken at∼ 1016 GeV
• Gauge unification (only insupersymmetric version)
NYS APS (October 15, 2004) Paul Langacker (Penn)
0
10
20
30
40
50
60
105
1010
1015
1 µ (GeV)
!i-
1(µ
)
SMWorld Average!
1
!2
!3
!S(M
Z)=0.117±0.005
sin2"
MS__=0.2317±0.0004
0
10
20
30
40
50
60
105
1010
1015
1 µ (GeV)
!i-
1(µ
)
MSSMWorld Average68%
CL
U.A.W.d.BH.F.
!1
!2
!3
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Seesaw model for small mν (butwhy are mixings large?)
• Quark-lepton (q − l) unification(⇒ charge quantization)
• q − l mass relations (work only forthird family in simplest versions)
• Proton decay? (simplest versionsexcluded)
• Doublet-triplet problem?
• String embedding? (breaking,families may be entangled in extra
dimensions)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
1636
mode exposure !Bm observed B.G. (ktï yr) (%) event
p " e+ + #
092 40 0 0.2 54
p " µ+ + #
092 32 0 0.2 43
p " e+ + $ 92 17 0 0.2 23
p " µ+ + $ 92 9 0 0.2 13
n " %__
+ $ 45 21 5 9 5.6p " e
+ + & 92 4.2 0 0.4 5.6
p " e+ + ' 92 2.9 0 0.5 3.8
p " e+ + ( 92 73 0 0.1 98
p " µ+ + ( 92 61 0 0.2 82
p " %__
+ K+
92 22K
+"%µ
+ (spectrum) 34 -- -- 4.2
prompt ( + µ+
8.6 0 0.7 11K
+"#
+#
0 6.0 0 0.6 7.9
n " %__
+ K0
92 2.0K
0"#
0#
0 6.9 14 19.2 3.0
K0"#
+#
- 5.5 20 11.2 0.8
p " e+ + K
092 10.7
K0"#
0#
0 9.2 1 1.1 8.7
K0"#
+#
-
2-ring 7.9 5 3.6 4.0 3-ring 1.3 0 0.1 1.7
p " µ+ + K
092 13.9
K0"#
0#
0 5.4 0 0.4 7.1
K0"#
+#
-
2-ring 7.0 3 3.2 4.9 3-ring 2.8 0 0.3 3.7
1031
1032
1033
1034
p " e+ #
0
e+ $
e+ '
e+ &
0
e+ K
0
µ+ #
0
µ+ $
µ+ '
µ+ &
0
µ+ K
0
%__
#+
%__
&+
%__
K+
n " e+ #
-
e+ &
-
µ+ #
-
µ+ &
-
%__
#0
%__
$%__
'%__
&0
%__
K0
lifetime limit (years)
KAMIMB3SK
Soudan2
Fig. 1. The obtained lifet ime limit of nucleons from SK–I (left figure) and their
comparisons with other experiments (right figure).
6. References
1. J. Ellis et al., Nucl. Phys. B202, 43 (1982)
2. Y.Fukuda et al., Phys. Rev. Let t . 81, 1562 (1998)
3. Y.Fukuda et al., Nucl. Instr. Meth. A501, 418 (2003)
4. H. Georgi and S. L. Glashow, Phys. Rev. Let t . 32, 438 (1974)
5. Y. Hayato et al., Phys. Rev. Let t . 83, 1529 (1999)
6. Jogesh C. Pat i and Abdus Salam, Phys. Rev. Let t . 31, 661 (1973)
7. For example, Jogesh C. Pat i, hep-ph/ 0005095.
8. N. Sakai and T. Yanagida, Nucl. Phys. B197, 533 (1982)
9. M. Shiozawa et al., Phys. Rev. Let t . 81, 3319 (1998)
10. M. Shiozawa, PhD thesis, University of Tokyo (1999)
11. S. Weinberg, Phys. Rev. D26, 287 (1982)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Superstrings
• Finite, “parameter-free” “theoryof everything” (TOE), includingquantum gravity
– 1-d string-like object
– Appears pointlike for resolution> M−1P ∼ 10−33 cm
– Vibrational modes → particles– Consistent in 10 space-
time dimensions → 6 mustcompactify to scale M−1P
– 4-dim supersymmetric gaugetheory below MP
– May also be solitons (branes),terminating open strings
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Problems– Which compactification manifold?
– Supersymmetry breaking? Cosmological constant?
– Many moduli (vacua). Landscape ideas - is there anypredictability left?
– Relation to supersymmetric standard model, GUT?
• Need theoretical progress and hints from experiment– TeV scale remnants, such as Z′, extended Higgs, exotics– SUSY breaking patterns
– Need very precise masses and couplings →International LinearCollider
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Future/present Experiments
• High energy colliders: the primary tool– The TEVATRON; Fermilab, 1.96 TeV p̄p, exploration
– The Large Hadron Collider (LHC); CERN, 14 TeV pp, highluminosity, discovery (Discovery machine for supersymmetry, Rpviolation, string remnants (e.g., Z′, exotics); or compositeness, dynamicalsymmetry breaking, Higgless theories, Little Higgs, large extra dimensions,
· · ·)– The International Linear Collider (ILC), in planning;
500 GeV-1 TeV e+e−, cold technology, high precision studies(Precision parameters to map back to string scale)
• Also, CP violation (B decays, electric dipole moments), flavor changingneutral currents (e.g., µ→eγ, µN→eN, B→φKs), neutrino physics
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Neutrinos as a Unique Probe: 10−33 − 10+28 cm
• Particle Physics
– νN, µN, eN scattering: existence/ properties of quarks, QCD
– Weak decays (n → pe−ν̄e, µ− → e−νµν̄e): Fermi theory, parityviolation, mixing
– Neutral current, Z-pole, atomic parity: electroweak unification,field theory, mt; severe constraint on physics to TeV scale
– Neutrino mass: constraint on TeV physics, grand unification,superstrings, extra dimensions; seesaw: mν ∼ m2q/MGUT
Xalapa (August, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Solar/atmosphericneutrino experiments
– Neutrinos have tinymasses (but largemixings)
– Standard Solar modelconfirmed
– First oscillation dipsobserved! (QM onlarge scale)
NYS APS (October 15, 2004) Paul Langacker (Penn)
00.20.40.60.8
11.21.41.61.8
1 10 102 103 10400.20.40.60.811.21.41.61.8
1 10 102 103 104
L/E (km/GeV)
Data
/Pre
dict
ion
(nul
l osc
.)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
3 ν Patterns
– Solar: LMA (SNO,KamLAND)
– ∆m2! ∼ 8×10−5 eV2,nonmaximal
– Atmospheric:|∆m2Atm| ∼ 2×10−3eV2, near-maximal mixing
– Reactor: Ue3 small
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
12
3
3
12
normal inverted
!
!
!"#$νL
h
NR
v = 〈φ〉
mD = hv
Dirac
!
!
""##
##""
νL
νcR $
!
""##
##""
νL
νL
Majorana
NYS APS (October 15, 2004) Paul Langacker (Penn)
Neutrino Implications/questions
• Key constituent of the Universe
• Why are the masses so small?– Planck/GUT scale? e.g., seesaw
or generalization, mν ∼ m2D/MN(may not be generic in strings)
• Are the neutrinos Dirac orMajorana?
– No SM gauge symmetry forbidsMajorana (but string, extended?)
– Neutrinoless double beta decay(ββ0ν) (inverted or degeneratespectra)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
12
3
3
12
normal inverted
!
!
!"#$νL
h
NR
v = 〈φ〉
mD = hv
Dirac
!
!
""##
##""
νL
νcR $
!
""##
##""
νL
νL
Majorana
NYS APS (October 15, 2004) Paul Langacker (Penn)
degenerate
NYS APS (October 15, 2004) Paul Langacker (Penn)
• What is the spectrum: number,mass scale/pattern, mixings
– Scale: β decay (KATRIN), ββ0ν,large scale structure (SDSS)
– Mixings and CP: reactor, longbaseline oscillation experiments,Solar
– Pattern: long baseline, ββ0ν,supernova
– Number: LSND? MiniBooNE
• Leptogenesis?
• Relic neutrinos?– Indirect: Nucleosynthesis, large
scale structure. Direct? (Z-burst?)
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
The Universe
• The concordance– 5% matter (including dark
baryons): CMB, BBN, Lymanα
– 25% dark matter (galaxies,clusters, CMB, lensing)
– 70% dark energy (Acceleration(Supernovae), CMB (WMAP))
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Perlmutter, Physics Today (2003)
Expansion History of the Universe
0.0
0.5
1.0
1.5
–20 –10 0
Billions Years from Today
10
0.05 today futurepast
Sca
le o
f the
Uni
vers
eR
elat
ive
to T
oday
's S
cale
After inflation,the expansion either...
collap
sesex
pand
s
forev
er
10.1
0.01
0.00
1
0.00
01relativebrightness
reds
hift
0
0.25
0.50.75
1
1.5
2.52
3
...or
alw
ays
dece
lera
ted
fir
st de
celera
ted, th
en acc
elerat
ed
• What is the dark matter?– Lightest neutralino in
supersymmetry (if R parityconserved)? Axion?
– Direct searches: LHC, ILC;cold dark matter searches; highenergy annihilation ν’s
– Gravitation lensing (SNAP),CMB (Planck)
• What is the dark energy?– Vacuum energy (cosmological constant);
time varying field (quintessence)?
– High precision supernova survey (SNAP);CMB (Planck)
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
101 10210−43
10−42
10−41
10−40
WIMP Mass [GeV]
Cros
s−se
ctio
n [c
m2 ]
(nor
mal
ised
to n
ucle
on)
• What is the dark matter?– Lightest neutralino in
supersymmetry (if R parityconserved)? Axion?
– Direct searches: LHC, ILC;cold dark matter searches; highenergy annihilation ν’s
– Axion searches (resonantcavities)
– Gravitation lensing (SNAP),CMB (Planck)
• What is the dark energy?– Vacuum energy (cosmological constant);
time varying field (quintessence)?
– High precision supernova survey (SNAP);CMB (Planck)
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
broken phase
becomes our world
unbroken phase
vWall
= 0φ
>> H
0CP CP_~ΓB + L
Sph
ΓB + L
Sph
q_q
qq
_
q_q
qq
_
• Why is there matter and notantimatter?
– nB/nγ ∼ 10−10, nB̄ ∼ 0– Electroweak baryogenesis
(extensions of MSSM)? Leptogenesis?Decay of heavy fields? CPTviolation?
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
• Why is there matter and notantimatter?
– nB/nγ ∼ 10−10, nB̄ ∼ 0– Electroweak baryogenesis?
Leptogenesis? Decay of heavyfields? CPT violation?
• The very beginning (inflation)– Relation to particle physics, strings, Λ?
– CMB (Planck); gravity waves (LISA)
NYS APS (October 15, 2004) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Second extreme example: time varying couplings and parameters
(Murphy et al, astro-ph/0209488)
TASI (June 5, 2003) Paul Langacker (Penn)
Far-Out Stuff
• LIV, VEP (e.g., maximum speeds, decays, (oscillations) of HE γ, e, gravitywaves (ν’s))
• LED, TeV black holes
• Time varying couplings
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)
-
The New Standard Model
• Standard model, supplemented with neutrino mass (Dirac orMajorana):
SU(3)×SU(2)×U(1)×classical relativity
• Mathematically consistent field theory of strong, weak,electromagnetic interactions
• Gauge interactions correct to first approximation to 10−16 cm
• Complicated, free parameters, fine tunings ⇒must be new physics
WIN 05 (June 11, 2005) Paul Langacker (Penn)
Conclusions
• The standard model is the correct description of fermions/gaugebosons down to ∼ 10−16 cm ∼ 11 TeV
• EWSB: consistent with light elementary Higgs but not proved
• Standard model is complicated → must be new physics
• Precision tests severely constrain new TeV-scale physics
• Promising theoretical ideas at Planck scale
• Promising experimental program at colliders, accelerators, lowenergy, cosmology
• Challenge to make contact between theory and experiment
Yoichiro Nambu Symposium (April 21, 2005) Paul Langacker (Penn)