T. D. Lee
description
Transcript of T. D. Lee
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T. D. Lee
A lecture given at the Workshop on Possible Parity Restoration at High Energy, on June 11, 2007, Beijing
(50 years since the discovery of parity nonconservation )
Symmetry and Asymmetry
in Electroweak Interaction
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• Symmetry Violation : the discovery
Present Status : the complexity
Restoration of P, C, T Symmetries
New Symmetry: A Unified View of
and
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(May 31, 1912 - Feb. 17, 1997)
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The initial setups of these two experiments on Co60
decay are exact mirror images, but the final electron distributions are not, as indicated by different readings on the counters.
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Discovery of Parity Nonconservation 5
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…
…
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•TCP invariance √
established by W. Pauli in 1955
•Parity Violation P X
right-left asymmetry
• Charge Conjugation Violation C X
particle-antiparticle asymmetry
both discovered by Wu et. al. in 1957
• Time Reversal Violation T X
• CP Violation CP X
proposed in 1957
discovered by Christenson, Cronin, Fitch and Turlay in 1964
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Symmetry Violation : the discovery
• Present Status : the complexity
Restoration of P, C, T Symmetries
New Symmetry: A Unified View of
and
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All known matter ( our kind of matter; i.e.,
, nuclei,
atoms, molecules, DNA, genes, earth, sun, stars,
galaxies, … ) are made of twelve elementary
particles:
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All known matter ( our kind of matter; i.e.,
, nuclei,
atoms, molecules, DNA, genes, earth, sun, stars,
galaxies, … ) are made of twelve elementary
particles:
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of these, only were known 50 years ago.
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: Cabibbo, Kobayashi, Maskawa
Both and are 3 x 3 unitary matrices. They are two corner stones of particle physics. Yet, they are very different!
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: neutrino mapping matrix
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CKM13
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Neutrino Mapping
Very different from !
How can we understand it ?
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Symmetry Violation : the discovery
Present Status : the complexity
• Restoration of P, C, T Symmetries
New Symmetry: A Unified View of
and
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Symmetry Violation : the discovery
Present Status : the complexity
• Restoration of P, C, T Symmetries
New Symmetry: A Unified View of
and
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• Equation of motion is symmetric, but solutions are not
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We assume P, C, T asymmetries are all due to
spontaneous Symmetry Breaking Mechanism of spin 0 Higgs Fields .
Without , all spin fields are Symmetry Conserving and of Zero Mass; these include graviton, photon, , quarks and leptons.
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Consequences
Besides and , there should exist and of heavier masses .
Can ILC be an effective means to
detect and ?
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Why are Higgs not yet seen?
Because of complex structure,
like Cooper pairs in superconductivity.
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Symmetry Violation : the discovery
Present Status : the complexity
Restoration of P, C, T Symmetries
• New Symmetry: A Unified View of
and
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New Symmetry: Neutrino Mass Operator is
invariant under:
21 A Simple Example Friedberg, Lee (HEP & NP 30(2006)591)
In the approximation of T invariance.
Consequence: There exists a zero mass neutrino state.
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Neutrino Mass Matrix (in terms of )
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pf
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Harrison and Scott, Phys. Lett. B535, 163(2002)
Z. Z. Xing, Phys. Lett. B533, 85(2002)
X. G. He and Z. Zee, Phys. Lett. B560, 87(2003)
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Thus, this example of new symmetry in is (approx.) correct ,
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• This new symmetry assumes T invariance.
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Questions and How to Improve
1. In
why (not ) approx. zero mass?
2. How about approx. sym. for
3. Can approx. T invariance be related
to masses of
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A Unified View of and
• 0th Approx.
• First Approx.
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R. Friedberg and T.D. Lee
arXiv: 0705.4156[hep-ph]
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Hidden Symmetry
• The quarks of charge
and of charge
in
are not mass eigenstates u, c, t and d, s, b
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• Likewise for leptons
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both and are unitary.
Likewise,
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both and are unitary.
Leptons
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assuming T inv.
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Mass Operator in sector (likewise for ) :31
0th approximation: T inv.
all real
New Symmetry: is invariant under
with
and
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gives
Proof
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neglecting T violation
With and
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from particledata group
(1) gives
(1)
consistent with particle data book value
Set
With T violation
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Thank you