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Parity-Violation with Electrons: Theoretical Perspectives

Parity-Violation with Electrons: Theoretical Perspectives. M.J. Ramsey-Musolf. 1970’s SLAC DIS Standard Model Atomic PV sin 2 q W ~ 10%. Prehistory. 1980’s Mainz 8 Be PV eq couplings MIT 12 C ~ 10%. PV: Past, Present, & Future. Modern Era.

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Parity-Violation with Electrons: Theoretical Perspectives

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  1. Parity-Violation with Electrons: Theoretical Perspectives M.J. Ramsey-Musolf

  2. 1970’s SLAC DIS Standard Model Atomic PV sin2qW ~ 10% Prehistory 1980’s Mainz 8Be PV eq couplings MIT 12C ~ 10% PV: Past, Present, & Future

  3. Modern Era 1990’s MIT GsE,M ~ few % JLab GA & rad corrections Mainz rn(r) APV sin2qW ~ 1% Anapole moment 2000’s SLAC Moller Standard Model & beyond JLab QWeak sin2qW < 1% APV Anapole moment JLab GAND Mainz HWI (DS=0): dD , Ag VVCS: An PV: Past, Present, & Future

  4. Future 2010’s JLab DIS-Parity Standard Model & beyond Moller (2) sin2qW < 1% 2020’s NLC Moller (3) sin2qW < 0.1% PV: Past, Present, & Future

  5. qq Mesons How does QCD make hadronic matter? PV & strange quarks Hybrids 2.5 exotic nonets 2.0 GPD’s: “Wigner Distributions” (X. Ji) mq-dependence of nuclear properties 1.5 1.0 L = 0 1 2 3 4 Pentaquark, Q+ Gluonic effects Quarks, Gluons, & the Light Elements Lattice QCD

  6. Effects in are much less pronounced than in , OZI violation Strange Quarks in the Nucleon:What have we learned? Jaffe ‘89 Hammer, Meissner, Drechsel ‘95 • Dispersion Relations • Narrow Resonances • High Q2 ansatz

  7. Effects in are much less pronounced than in , HAPPEX SAMPLE Strange Quarks in the Nucleon:What have we learned?

  8. Theory: how do we understand dynamics of small ss effects in vector current channel ? Challenge to understand QCD at deep, detailed level Unknown constants Strange Quarks in the Nucleon: What have we learned? • 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

  9. Happex projected G0 projected SAMPLE 2003 Lattice QCD theory Dispersion theory Chiral perturbation theory “reasonable range” for slope Q2 -dependenceof GsM

  10. See also Leinweber et al Lattice Computations Dong, Liu, & Williams (1998) Lewis, Wilcox, Woloshyn (2003) • Quenched QCD • Wilson fermions • 100 gauge configurations • 300-noise estimate/config • Quenched QCD • Wilson fermions • 2000 gauge configurations • 60-noise estimate/config

  11. Lattice calculation • Charge symmetry • Measured octet m.m.’s • Chiral symmetry • Unquenching Lattice Computations Leinweber et al

  12. 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

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

  14. Slope of GMs Strong interaction scattering amplitudes e+ e- K+ K-, etc. Dispersion theory Jaffe Hammer, Drechsel, R-M

  15. All orders Perturbation theory (1-loop) Dispersion theory Hammer & R-M

  16. All orders  resonance • S-quarks are not inert • Non-perturbative effects dominate (LEC’s) Perturbation theory (1-loop) Dispersion theory Hammer & R-M

  17. Experiment & lattice will give an answer 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 Models & exp’t suggest cancellations

  18. dRA “Reasonable range”: lattice & disp rel Combining PT, dispersion theory, & lattice QCD SAMPLE

  19. Radiative Corrections & the Hadronic Weak Interaction • GAe • N !D • PV p photo- and electro-production (threshold) • Vector analyzing power (gg)

  20. 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).

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

  22. 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

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

  24. 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

  25. Zhu, R-M pN!pN ~ 5% O(p2) chiral corrections ~ few % Rad corrections, “anapole” ~ 25% Study GAND(Q2)/ GAND(0) Transition Axial Form Factor Off Diagonal Goldberger-Treiman Relation

  26. Axial response , GANDonly Nonzero ALR(Q2= 0) GAND & “dD”””, ALR ~ Q2 (1-2sin2qW) Zhu, Maekawa, Sacco, Holstein, R-M Measuring GAND(Q2)

  27. c symmetry not sufficient S-Wave: Parity-violating P-Wave: Parity-conserving Weak interactions of s-quarks are puzzling Hyperon weak decays

  28. E1 (PV) M1 (PC) Th’y Exp’t Weak interactions of s-quarks are puzzling

  29. S-Wave P-Wave Fit matrix elements Weak interactions of s-quarks are puzzling Resonance saturation Holstein & Borasoy S11 Roper

  30. S-Wave P-Wave Fit matrix elements Close gap with aBB’ S/P wave fit Weak interactions of s-quarks are puzzling Resonance saturation Holstein & Borasoy S11 Roper

  31. Is deviation from QCD-based expectations due to presence of s-quarks or more fundamental dynamics? Natural Fit Weak interactions of s-quarks are puzzling

  32. Low energy constant PV, E1 Amplitude PV Asymmetry Large NC , spin-flavor SU(4) Finite NC We have a DS=0 probe Use PV to filter out EM transition Zhu, Maekawa, Holstein, MR-M

  33. dD ~ gp dD ~ 25gp We have a DS=0 probe Naïve dimensional analysis (NDA) Resonance saturation

  34. dD= 0 , GANDonly dD= 100 gp , enhanced HWDS=0 ALR ~ Q2 (1-2sin2qW) Zhu, Maekawa, Sacco, Holstein, R-M Measuring dD

  35. Measure Q2-dependence of ALR to learn • dD • GAND(Q2)/ GAND(0) • RAD • MINERVA: GAND(0) ? N!D Transition

  36. What specifically could we learn? Vud 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

  37. + Direct probe Vector Analyzing Power V=g: VVCS Re Mg*(Mggbox+Mggcross) Rosenbluth Im Mg*Mggbox VAP V=W,Z: Electroweak VVCS Re MV*(MVgbox+MVgcross) b-decay, RA,… Im MV*MVgbox b-decay T-violation

  38. q=1460 SAMPLE Mott: MN!1 kI=1, r2 EFT to O(p2) Diaconescu, R-M O(p0) O(p4) Vector Analyzing Power

  39. Dynamical p’s? q=300 Constrained by SAMPLE Vector Analyzing Power

  40. Theory for RA good to ~ 25% Further test of RAD ; dD & HWqq EFT for low energy good to ~ 25%; more tests! New window on electroweak VVCS: b-decay, sin2qW,… Radiative Corrections & the Hadronic Weak Interaction • GAe • N !D • PV p photo- and electro-production (threshold) • Vector analyzing power (gg)

  41. Atomic PV N deep inelastic sin2W e+e- LEP, SLD SLAC E158 (ee) JLab Q-Weak (ep) (GeV) Weak Mixing Angle: Scale Dependence Czarnecki, Marciano Erler, Kurylov, MR-M

  42. SUSY loops  SUSY dark matter ->e+e n is Majorana RPV 95% CL fit to weak decays, MW, etc. Comparing Qwe and QWp Kurylov, Su, MR-M

  43. QWP = 0.0716 QWe = 0.0449 Experiment SUSY Loops E6 Z/ boson RPV SUSY Leptoquarks SM SM Comparing Qwe and QWp Erler, Kurylov, R-M

  44. LinearCollider e-e- Atomic PV N deep inelastic DIS-Parity, JLab DIS-Parity, SLAC sin2W e+e- LEP, SLD SLAC E158 (ee) JLab Q-Weak (ep) Moller, JLab (GeV) Additional PV electron scattering ideas Czarnecki, Marciano Erler et al.

  45. SUSY loops E158 &Q-Weak Linear collider JLab Moller RPV 95% CL Comparing Qwe and QWp Kurylov, R-M, Su  SUSY dark matter

  46. e RPV Loops p SUSY effects Comparing AdDIS and Qwp,e

  47. “DIS Parity” SUSY loops E158 &Q-Weak Linear collider JLab Moller RPV 95% CL Comparing Qwe and QWp Kurylov, R-M, Su  SUSY dark matter

  48. ~0.4% Different PDF fits E=11 GeV q=12.50 Sacco, R-M preliminary Higher Twist “Pollution”

  49. Sacco & R-M preliminary Castorina & Mulders • Open issues • QCD evolution • Double handbag • Moment inversion Higher Twist “Pollution”

  50. 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 exp’t & theory….

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