ParityViolation with Electrons: Theoretical Perspectives

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Parity-Violation with Electrons Theoretical
Perspectives
M.J. Ramsey-Musolf
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PV Past, Present, Future
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PV Past, Present, Future
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PV Past, Present, Future
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Quarks, Gluons, the Light Elements
Lattice QCD
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Strange Quarks in the NucleonWhat have we
learned?
Jaffe 89 Hammer, Meissner, Drechsel 95

• Dispersion Relations
• Narrow Resonances
• High Q2 ansatz

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Strange Quarks in the NucleonWhat have we
learned?
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Strange Quarks in the Nucleon What have we
learned?

• Strange quarks dont appear in Quark Model
  picture of the nucleon

• Perturbation theory may not apply

?QCD / ms 1 No HQET
mK / ?c 1/2 ?PT ?

• Symmetry is impotent

J?s J?B 2 J?EM, I0
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Q2 -dependenceof GsM
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Lattice Computations
See also Leinweber et al
Dong, Liu, Williams (1998)
Lewis, Wilcox, Woloshyn (2003)

• Quenched QCD
• Wilson fermions
• 2000 gauge configurations
• 60-noise estimate/config

• Quenched QCD
• Wilson fermions
• 100 gauge configurations
• 300-noise estimate/config

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Lattice Computations
Leinweber et al
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What ?PT can (cannot) say
Ito, R-M Hemmert, Meissner, Kubis
Hammer, Zhu, Puglia, R-M
Strange magnetism as an illustration
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What ?PT can (cannot) say
Strange magnetism as an illustration
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Dispersion theory
Jaffe Hammer,
Drechsel, R-M
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Dispersion theory
Hammer R-M
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Dispersion theory
Hammer R-M
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Dispersion theory
Models expt suggest cancellations
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Combining ?PT, dispersion theory, lattice QCD
SAMPLE
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Radiative Corrections the Hadronic Weak
Interaction

• GAe
• N !D
• PV p photo- and electro-production (threshold)
• Vector analyzing power (gg)

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at Q20.1 (GeV/c)2

• s-quarks contribute less than 5 (1s) to the
  protons magnetic form factor.
• protons axial structure is complicated!

R. Hasty et al., Science 290, 2117 (2000).
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Axial Radiative Corrections
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Anapole Effects
Hadronic PV
Cant account for a large reduction in GeA
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Nuclear PV Effects
PV NN interaction
Carlson, Paris, Schiavilla Liu,
Prezeau, Ramsey-Musolf
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SAMPLE Results
R. Hasty et al., Science 290, 2117 (2000).
at Q20.1 (GeV/c)2

• s-quarks contribute less than 5 (1s) to the
  protons magnetic moment.

200 MeV update 2003 Improved EM radiative
corr. Improved acceptance model Correction for p
background
125 MeV no p background similar sensitivity to
GAe(T1)
E. Beise, U Maryland
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Transition Axial Form Factor
Off Diagonal Goldberger-Treiman Relation
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Measuring GAND(Q2)
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Weak interactions of s-quarks are puzzling
Hyperon weak decays
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Weak interactions of s-quarks are puzzling
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Weak interactions of s-quarks are puzzling
Resonance saturation
Holstein Borasoy
S11 Roper
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Weak interactions of s-quarks are puzzling
Resonance saturation
Holstein Borasoy
S11 Roper
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Weak interactions of s-quarks are puzzling
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We have a DS0 probe
Use PV to filter out EM transition
Zhu, Maekawa, Holstein, MR-M
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We have a DS0 probe
Naïve dimensional analysis (NDA)
Resonance saturation
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Measuring dD
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N!D Transition
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Vector Analyzing Power

• T-odd, P-even correlation
• Doubly virtual compton scattering (VVCS) new
  probe of nucleon structure
• Implications for radiative corrections in
  other processes GEp/GMp, b-decay
• SAMPLE, Mainz, JLab experiments

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Vector Analyzing Power
Vg VVCS Re Mg(MggboxMggcross) Rosenbluth Im
MgMggbox VAP
VW,Z Electroweak VVCS Re MV(MVgboxMVgcross) b-
decay, RA, Im MVMVgbox b-decay
T-violation
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Vector Analyzing Power
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Vector Analyzing Power
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Radiative Corrections the Hadronic Weak
Interaction

• GAe
• N !D
• PV p photo- and electro-production (threshold)
• Vector analyzing power (gg)

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Weak Mixing Angle Scale Dependence
Czarnecki, Marciano Erler, Kurylov, MR-M
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Comparing Qwe and QWp
Kurylov, Su, MR-M
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Comparing Qwe and QWp
Erler, Kurylov, R-M
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Additional PV electron scattering ideas
Czarnecki, Marciano Erler et al.
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Comparing Qwe and QWp
Kurylov, R-M, Su
??? SUSY dark matter
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Comparing AdDIS and Qwp,e
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Comparing Qwe and QWp
Kurylov, R-M, Su
??? SUSY dark matter
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Higher Twist Pollution
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Higher Twist Pollution
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Tasks for the modern era future
Strange quarks

• Finish the experimental program
• Credible, unquenched lattice calculations

Rad corrections

• Further tests of electroweak VVCS with N!D, VAP
• Theory quark mass (mp) dependence
• Measure dD

SM new physics

• DIS-Parity Is there significant I-violation as
  suggested by NuTeV?
• Theory how big is twist pollution?
• Theory relating rn(r) APV

Hardronic PV

• Lots of new expt theory.