Dynamical Electroweak Breaking @ Dynamical Electroweak Breaking @ LHCLHC
Francesco SanninoFrancesco Sannino
MC-Workshop MC-Workshop Frascati - 2006 Frascati - 2006
The Niels Bohr Institute
• Origin of Mass of weak gauge bosons, quarks and leptons is unknown.
• Strong Interactions are not fully understood/explored.
• Unnaturally small Neutron Electric Dipole Moment Strong CP problem:
New Challenges from Cosmology.
• Dark Energy/Matter
…….is not so standard.is not so standard
Strong Dynamics
Focus on two aspects of the SMFocus on two aspects of the SM
Understanding
New
Origin of Mass for the weak gauge bosons, quarks …
as
..and Beyond..and Beyond
We can already test New Physics! Kennedy,Lynn, Peskin-Takeuchi, Altarelli-Barbieri, Bertolini-Sirlin,
Marciano-Rosner,..:
Electroweak Precision MeasurementsElectroweak Precision Measurements
Present DataPresent Data
hep-ex/0509008 Now: S = 0.07±0.10
mH=150 GeV
Dutta, Hagiwara and Yan ph/0603038.Weaken constraints
Exact Super Symmetry:Exact Super Symmetry:
Fermions ↔ Bosons
Fermion’s custodial symmetry protects the Bosons
Observe: susy partners
Composite ScalarComposite Scalar:
Recall Superconductivity
Substructure resolved at scale ΛS
Observe: New Bound States
Quasi Goldstone Boson:
Protected by spontaneously broken global symmetries.
Near Continuous Quantum Phase Transition
Zero-temperature Bose – Einstein Condensation Lorentz symmetry is broken.
Chiral Phase Transition at zero temperature. Lorentz symmetry is intact.
Technicolor
New Strong Interactions at ~ 250 GeV [Weinberg, Susskind]
Natural to use QCD-like dynamics.
Problems with the Old Models
• S-parameter: too large
• Large Flavor Changing Neutral Currents (FCNC)
• Limited knowledge of strong dynamics!
should be sufficiently larger than
Fermion masses versus FCNCFermion masses versus FCNC
PNGMasses
SM-FermionMasses
FCNCOperators
250TC GeV ETC
to reduce FCNC.Progress: Appelquist, Christensen, Piai, Shrok
Near Conformal Properties
Λ T C
α
q
n o n -c o n fo rm a l
Λ T C
α
qΛ E T C
Λ = 1 0 0 1 0 0 0 E T C - Λ T C
n ea r-c o n fo rm a l
α
β
α *α c
Holdom
Appelquist
Miransky, Yamawaki
Cohen and Georgi…
Critical Number of techniflavors
For fermions in the fundamental representation near conformal means:
The number of techndoublets is
The S-parameter for fermions in the fundamental is
Near conformal for N=2 means Nf/2=4 which yields:
Experimentally S = 0.07±0.10
Still too large S-parameter
Appelquist - Sannino
The New Model
Near conformal for, Nf 2
Small FCNC + Top mass
OK with precision data.
Light Composite Higgs
Dark Matter Sannino-Tuominen, hep-ph/0405209
Hong, Hsu, Sannino, hep-ph/0406200
Dietrich, Sannino and Tuominen, hep-ph/0505059, hep-ph/0510217
Evans-Sannino, hep-ph/0512080
Gudnason, Kouvaris and Sannino, hep-ph/0603014
`t Hooft - Large N
Corrigan and Ramond `79
Larks
Kiritsis and Papavassiliou `90.
Ryttov and F.S. `05
Helpful for MC ???
A-type:
QCD vacuum properties, spectrum and confinement/chiral symmetry, finite temperature and density. Armoni-Shifman-Veneziano, Sannino-Shifman, Sannino, (Finite Temperature. Chiral Symmetry vs Confinement) Frandsen-Kouvaris-Sannino (Finite matter density)Sannino-Schechter (..in progress)
N=1 Supersymmetric-Spectrum Merlatti-SanninoFeo-Merlatti-Sannino
S-type:
Composite Higgs from Higher Representations Sannino
Not ruled out, LCH and DMDietrich-Tuominen-Sannino, Hong-Hsu-Sannino, Sannino-TuominenEvans-SanninoGudnason, Kouvaris and Sannino
Phase Diagram for the S-Theory
Phase diagram as function of Nf and N. [Sannino-Tuominen]
For N=2,3,4,5 we have that Nf= 2
S-parameter
• δ ~ 0.013 due to near conformal dynamics [Sundrum-Hsu, Appelquist-Sannino].
• The estimate for S in the S-type model is:
Model versus EWPData
68% contour
Electron (m2) and Neutrino (m1) Dirac masses.
Standard Hypercharge Assignment
150 GeV
4th Lepton Family
A natural LCH*
• Via trace anomaly and the behavior of the underlying beta function near the chiral/conformal phase transition we show:
Dark Side of the 5th Force
NussinovBarr, Chivukula and Farhi
Technibaryon, DD
Universe Charge Neutrality.
Chemical Equilibrium
Taking care of the Sphaleron Processes
• MH ~ light
• Fourth Family of Leptons around the Z mass.
• 6 light scalars will be observed.
• Electroweak baryongenesis. Possible Strongly First order phase transition.
• Lattice Simulations are possible
• DM candidate-component
• Unification, Holography….
Predictions and Outlook
Small parameters stay small under radiative corrections.
The electron Mass
If set to zero the U(1)L× U(1)R forbids its regeneration
Naturalness begs an explanation of the origin of mass.
No conflict with any small value of the electron mass
NaturalityNaturality