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Parity Violation: Past, Present, and Future

Parity Violation: Past, Present, and Future. M.J. Ramsey-Musolf. NSAC Long Range Plan. What is the structure of the nucleon? What is the structure of nucleonic matter? What are the properties of hot nuclear matter? What is the nuclear microphysics of the universe?

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Parity Violation: Past, Present, and Future

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  1. Parity Violation: Past, Present, and Future M.J. Ramsey-Musolf

  2. NSAC Long Range Plan • What is the structure of the nucleon? • What is the structure of nucleonic matter? • What are the properties of hot nuclear matter? • What is the nuclear microphysics of the universe? • What is to be the new Standard Model?

  3. NSAC Long Range Plan • What is the structure of the nucleon? • What is the structure of nucleonic matter? • What are the properties of hot nuclear matter? • What is the nuclear microphysics of the universe? • What is to be the new Standard Model? Parity-Violating Electron Scattering

  4. Outline • PVES and Nucleon Structure • PVES and Nucleonic Matter • PVES and the New Standard Model

  5. QPW, GPW APV APC* GPW [ ] QPW+ F(Q2, ) Parity-Violating Asymmetry

  6. PV Electron Scattering Experiments MIT-Bates Mainz SLAC Jefferson Lab

  7. PV Electron Scattering Experiments Deep Inelastic eD (1970’s) PV Moller Scattering (now) Deep Inelastic eD (2005?) SLAC

  8. PV Electron Scattering Experiments MIT-Bates Elastic e 12C (1970’s - 1990) Elastic ep, QE eD (1990’s - now)

  9. PV Electron Scattering Experiments Mainz QE e 9Be (1980’s) Elastic ep (1990’s - now)

  10. PV Electron Scattering Experiments Elastic ep: HAPPEX, G0 (1990’s - now) Elastic e 4He: HAPPEX (2003) Elastic e 208Pb: PREX QE eD, inelastic ep: G0 (2003-2005?) Elastic ep: Q-Weak (2006-2008) Moller, DIS eD (post-upgrade?) Jefferson Lab

  11. Constituent quarks (QM) Current quarks (QCD) QP ,P FP2(x) PVES and Nucleon Structure What are the relevant degrees of freedom for describing the properties of hadrons and why?

  12. PVES and Nucleon Structure Why does the constituent Quark Model work so well? • Sea quarks and gluons are “inert” at low energies • Sea quark and gluon effects are hidden in parameters and effective degrees of freedom of QM (Isgur) • Sea quark and gluon effects are hidden by a “conspiracy” of cancellations (Isgur, Jaffe, R-M) • Sea quark and gluon effects depend on C properties of operator (Ji)

  13. Strange quarks in the nucleon: • Sea quarks • ms ~ QCD • 20% of nucleon mass, possibly -10% of spin What role in electromagnetic structure ? PVES and Nucleon Structure What are the relevant degrees of freedom for describing the properties of hadrons and why?

  14. Effects in GP suppressed by QCD/mq) 4 < 10 -4 QCD ~ 150 MeV Neglect them We can uncover the sea with GPW Light QCD quarks: u mu ~ 5 MeV d md ~ 10 MeV s ms ~ 150 MeV Heavy QCD quarks: c mc ~ 1500 MeV b mb ~ 4500 MeV t mt ~ 175,000 MeV

  15. ms ~ QCD : No suppression not necessarily negligible We can uncover the sea with GPW Light QCD quarks: u mu ~ 5 MeV d md ~ 10 MeV s ms ~ 150 MeV Heavy QCD quarks: c mc ~ 1500 MeV b mb ~ 4500 MeV t mt ~ 175,000 MeV

  16. Lives only in the sea We can uncover the sea with GPW Light QCD quarks: u mu ~ 5 MeV d md ~ 10 MeV s ms ~ 150 MeV Heavy QCD quarks: c mc ~ 1500 MeV b mb ~ 4500 MeV t mt ~ 175,000 MeV

  17. GP = QuGu + QdGd+ QsGs Gn = QuGd + QdGu+ QsGs, isospin GPW = QuWGu + QdWGd+ QsWGsZ0 SAMPLE (MIT-Bates), HAPPEX (JLab), PVA4 (Mainz), G0 (JLab) Gu , Gd , Gs Parity-Violating Electron Scattering Kaplan and Manohar McKeown Neutral Weak Form Factors

  18. Parity-Violating Electron Scattering Separating GEW , GMW , GAW GMW , GAW SAMPLE GMW , GEW HAPPEX, PVA4 GMW , GEW , GAW : Q2-dependence G0 Published results: SAMPLE, HAPPEX

  19. Models for s Radiative corrections at Q2=0.1 (GeV/c)2 • s-quarks contribute less than 5% (1s) to the proton’s magnetic form factor. • proton’s axial structure is complicated! R. Hasty et al., Science 290, 2117 (2000).

  20. “Anapole” effects : Hadronic Weak Interaction + Nucleon Green’s Fn : Analogous effects in neutron -decay, PC electron scattering… Axial Radiative Corrections

  21. Zhu et al. Zhu, Puglia, Holstein, R-M (cPT) Maekawa & van Kolck (cPT) Riska (Model) “Anapole” Effects Hadronic PV Can’t account for a large reduction in GeA

  22. Suppressed by ~ 1000 Nuclear PV Effects PV NN interaction Carlson, Paris, Schiavilla Liu, Prezeau, Ramsey-Musolf

  23. D2 200 MeV data Mar 2003 H2 Zhu, et al. Radiative corrections SAMPLE Results R. Hasty et al., Science 290, 2117 (2000). atQ2=0.1 (GeV/c)2 • s-quarks contribute less than 5% (1s) to the proton’s 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(T=1) E. Beise, U Maryland

  24. Strange Quark Form Factors Theoretical Challenge: • Strange quarks don’t 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, I=0

  25. Theoretical predictions

  26. Happex projected G0 projected Lattice QCD theory Dispersion theory Chiral perturbation theory “reasonable range” for slope Q2 -dependenceof GsM

  27. Kaon loop contributions (calculable) Unknown low-energy constant (incalculable) What PT can (cannot) say Ito, R-M Hemmert, Meissner, Kubis Hammer, Zhu, Puglia, R-M Strange magnetism as an illustration

  28. NLO, unknown LEC { } LO, parameter free NLO, cancellation What PT can (cannot) say Strange magnetism as an illustration

  29. Slope of GMs Strong interaction scattering amplitudes e+ e- K+ K-, etc. Dispersion theory gives a model-independent prediction Jaffe Hammer, Drechsel, R-M

  30. Perturbation theory (1-loop) Dispersion theory gives a model-independent prediction Hammer & R-M

  31. All orders  resonance Perturbation theory (1-loop) Dispersion theory gives a model-independent prediction Hammer & R-M

  32. Can’t do the whole integral • Are there higher mass excitations of s s pairs? • Do they enhance or cancel low-lying excitations? ? Dispersion theory gives a model-independent prediction Experiment will give an answer

  33. PVES and Nucleonic Matter What is the equation of state of dense nucleonic matter? We know a lot about the protons, but lack critical information about the neutrons

  34. ~ 0.1 PVES and Nucleonic Matter Donnelly, Dubach, Sick The Z0 boson probes neutron properties QW = Z(1 - 4 sin2W) - N Horowitz, Pollock, Souder, & Michels PREX (Hall A): 208Pb

  35. PREX PVES and Neutron Stars Neutron star Horowitz & Piekarewicz 208Pb Crust thickness decreases with Pn Skin thickness (Rn-Rp) increases with Pn

  36. PVES and Neutron Stars Horowitz & Piekarewicz Neutron star properties are connected to density-dependence of symmetry energy PREX probes Rn-Rp a meter of E ( r )

  37. PVES and the New Standard Model We believe in the Standard Model, but it leaves many unanswered questions • What were the symmetries of the early Universe and how were they broken? • What is dark matter? • Why is there more matter than anti-matter?

  38. Present universe Early universe Standard Model High energy desert Weak scale Planck scale PVES and the New Standard Model

  39. Present universe Early universe Standard Model High energy desert Weak scale Planck scale PVES and the New Standard Model A “near miss” for grand unification

  40. Present universe Early universe Standard Model High energy desert Weak scale Planck scale PVES and the New Standard Model Weak scale is unstable against new physics in the desert GF would be much smaller

  41. Present universe Early universe Standard Model High energy desert Weak scale Planck scale PVES and the New Standard Model Not enough CP-violation for weak scale baryogenesis

  42. SU(2)L U(1)Y Neutral current mixing depends on electroweak symmetry JmWNC = Jm0 + 4 Q sin2WJmEM

  43. Standard Model sin2W (GeV) MZ Weak mixing also depends on scale Czarnecki & Marciano Erler, Kurylov, R-M

  44. sin2W() depends on particle spectrum

  45. sin2W() depends on particle spectrum

  46. sin2W() depends on particle spectrum

  47. QeW = -1 + 4 sin2W QPW = 1 - 4 sin2W QCsW = Z(1 - 4 sin2W) - N New Physics & Parity Violation sin2W is scale-dependent

  48. Atomic PV N deep inelastic sin2W e+e- LEP, SLD SLAC E158 JLab Q-Weak (GeV) Weak mixing also depends on scale

  49. Fermions Bosons sfermions gauginos Higgsinos Charginos, neutralinos Additional symmetries in the early universe can change scale-dependence Supersymmetry

  50. Present universe Early universe Standard Model Weak scale Planck scale Electroweak & strong couplings unify with supersymemtry Supersymmetry Weak scale & GF are protected

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