1. 1 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Recent Results from Parity Violation Electron Scattering Experiments at JLab (and elsewhere) Xiaochao Zheng 郑晓超 (Univ. of Virginia) August 2, 2011 The Physics of PVES on nucleon/nuclear targets Nucleon strangeness structure study: results from MAINZ A4, G0 and HAPPEX-III Nuclear Physics study: results from PREX Standard Model study: Qweak and PVDIS Plan for PVDIS (and Moller) at the upgraded JLab

2. 2 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Parity Violation parity The parity symmetry: the physical laws behind all phenomena is the same as those behind their mirror images (The Lagrangian is invariant under transformation ) ; This symmetry is broken in weak interactions; Weak interaction is carried by charged or neutral weak currents, described under the framework SU(2) L xU(1) Y Chen-Ning Yang Tsung-Dao Lee Chien-Shiung Wu "for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles" 1957 Nobel Prize in Physics: with q W. experimental proof using beta decay of 60 Co.

3. 3 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Parity Violating Electron Scattering Weak Neutral Current (WNC) Interactions at Q 2 << M Z 2 Longitudinally Polarized Electron Scattering off Unpolarized Fixed Targets longitudinally polarized e The Physics accessible by PVES: elastic scattering from the proton: strange form factors or nucleon weak charge from (heavy) nuclei: nuclear physics deep inelastic scattering: weak structure of the nucleon, quark neutral weak couplings A4, HAPPEX, G0 PREX Qweak PVDIS

4. 4 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Nucleon Strange Form Factors

5. 5 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Nucleon in QCD Nucleon Form Factors Electromagnetic probe hadronic flavor structure: (these encode information on spatial distributions of charge & magnetization, but not enough for flavor separation) s and s have different spatial distributions What would non-zero strange form factors imply? G s E ≠ 0 G s M ≠ 0 s and s have different magnetization distributions, may contribute to magnetic moment, etc. Neutral weak probe the same hadronic flavor structure, with different couplings: cVucVu cVdcVd cVscVs

6. 6 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Isolating individual form factors: vary kinematics or target Forward angle Backward angle “anapole” radiative corrections are problematic proton + isospin rotation, and assuming G s,p = G s, n + linear combinations of G E Z and G M Z linear combinations of G E S and G M S

7. 7 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Kent Paschke User’s Group Annual Meeting, JLab - June 7, 2011 Experimental Overview SAMPLE HAPPEX Precision spectrometer, integrating Forward angles A4 open geometry, integrating, back-angle only Open geometry Fast counting calorimeter for background rejection Forward and Backward angles G0 Open geometry Fast counting w/ magnetic spectrometer + TOF Forward and Backward angles over a range of Q 2

8. 8 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Nucleon Strange Form Factor Program Expt/Lab Target / Angle Q 2 (GeV 2 ) Apv (ppm) SensitivityComplete SAMPLE/Bates SAMPLE I LH2/1450.1-6GM + 0.4GA2000 SAMPLE IILD2/1450.1-8GM + 2GA2004 SAMPLE IIILD2/1450.04-4GM + 3GA2004 HAPPEx/JLab HAPPExLH2/12.50.47-15GE + 0.39GM1999 HAPPEx IILH2/60.11-1.6GE + 0.1GM2006, 2007 HAPPEx He4He/60.11+6GE2006, 2007 HAPPEx IIILH2/140.63-24GE + 0.5GM2011 PV-A4/Mainz LH2/350.23-5GE + 0.2GM2004 LH2/350.11-1.4GE + 0.1GM2005 LH2/1450.23-17GE + ηGM + η’GA 2009 LH2/350.63-28GE + 0.64GM(2009) G0/JLab ForwardLH2/350.1 to 1-1 to -40GE + ηGM2005 BackwardLH2/LD2/1100.23, 0.63-12 to -45GE + ηGM + η’GA 2009

9. 9 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan World Data on G s all forward-angle proton data “Form Factor” error: precision of EMFF (including 2γ) and Anapole correction

10. 10 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan World Data on G s all forward-angle proton data At Q 2 ~ 0.1 GeV 2, G s < few percent of G p “Form Factor” error: precision of EMFF (including 2γ) and Anapole correction

11. 11 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan World Data on G s all forward-angle proton data At Q 2 ~ 0.1 GeV 2, G s < few percent of G p “Form Factor” error: precision of EMFF (including 2γ) and Anapole correction Q 2 ~ 0.22 G0-backward A4-backward A4-forward

12. 12 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan World Data on G s all forward-angle proton data At Q 2 ~ 0.1 GeV 2, G s < few percent of G p “Form Factor” error: precision of EMFF (including 2γ) and Anapole correction Q 2 ~ 0.22 Q 2 ~ 0.62 G0-backward A4-backward A4-forward

13. 13 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan World Data on G s all forward-angle proton data At Q 2 ~ 0.1 GeV 2, G s < few percent of G p “Form Factor” error: precision of EMFF (including 2γ) and Anapole correction Q 2 ~ 0.22 Q 2 ~ 0.62 G0-backward A4-backward A4-forward Strange form factors contribute at most a few % to overall vector form factors… except maybe near Q 2 = 0.6…

14. 14 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan HAPPEX-III Results (“Close-book” measurement) A PV = -23.80  0.78 (stat)  0.36 (syst) ppm at Q 2 = 0.6241 ± 0.0028 GeV 2 G s E + 0.52 G s M = 0.003 ± 0.010 (stat) ± 0.004 (syst) ± 0.009 (FF) See talk by Mark Dalton, on HAPPEX-III Ahmed et al. (HAPPEX Collaboration) arXiv:1107.0913 [nucl-ex] HAPPEX-III: Ran in Aug-Oct 2009

15. 15 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan HAPPEX-III Results (“Close-book” measurement) A PV = -23.80  0.78 (stat)  0.36 (syst) ppm at Q 2 = 0.6241 ± 0.0028 GeV 2 G s E + 0.52 G s M = 0.003 ± 0.010 (stat) ± 0.004 (syst) ± 0.009 (FF) See talk by Mark Dalton, on HAPPEX-III Ahmed et al. (HAPPEX Collaboration) arXiv:1107.0913 [nucl-ex] HAPPEX-III: Ran in Aug-Oct 2009 Strange form factors contribute at most a few % to overall vector form factors at all Q 2 measured s and sbar have similar spatial distribution and their spin/magnetic moments largely cancel, when viewed via electron elastic scattering.

16. 16 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Weak Charge Distribution of Heavy Nuclei – Testing Nuclear Physics and Beyond

17. 17 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Weak Charge Distribution of Heavy Nuclei Nuclear theory predicts a neutron “skin” on heavy nuclei 208 Pb Neutron distribution is challenging to interpret from strongly interacting probes (protons, pions, etc.), and is not accessible to the charge-sensitive photon. protonneutron Electric charge10 Weak charge~0.081 But the weak interaction sees the neutrons clearly: See talk by Dustin McNulty

18. 18 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan A crucial calibration point for nuclear theory ( R.J. Furnstahl ) The single measurement of F n translates to a measurement of R n via mean-field nuclear models R n calibrates the equation of state of neutron rich matter Example: important in describing neutron star mass vs. radius and cooling processes. neutron stars 208 P b

19. 19 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PREX (Pb Radius EXperiment) Results and Interpretation ppm at Q 2 = 0.00906 GeV 2, 5 o angle, Statistics limited (9%) Systematic error goal achieved ! (2%) 9.2 %2.0 % A PV ~ 0.6 ppm, original goal: 3% error Ran in April-June 2010: confirming the “neutron skin” ! Preliminary estimate from C.J. Horowitz, confirming the “neutron skin” !

20. 20 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PREX-II (25 PAC days, submitted to PAC38) PREX-II projected

21. 21 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Testing the EW Standard Model – SU(2) L xU(1) Y

22. 22 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Select Results on the Weak Mixing Angle (expected) figure from K. Kumar, Seattle 2009 EIC Workshop EW talks SLAC E158: Moller scattering, ran in 2002-2003

23. 23 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Weak Neutral Couplings A V V A g A,V follow PDG convention Different conventions exist, here:

24. 24 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan SAMPLE C 2u +C 2d 1.25 1.5 1.75 1.0 0.75 0.5 0.25 0 -0.5 -0.75 C 2u -C 2d - 0.250.50.250- 0.5 PVES provides a factor of 5 increase in precision of Standard Model test PRL99,122003(2007) Quark Weak Neutral Couplings C 1,2q with recent PVES data without JLab data all are 1 s limit PDG best fit SLAC/ Prescott

25. 25 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan SAMPLE C 2u +C 2d 1.25 1.5 1.75 1.0 0.75 0.5 0.25 0 -0.5 -0.75 C 2u -C 2d - 0.250.50.250- 0.5 Quark Weak Neutral Couplings C 1,2q with recent PVES data and Qweak (projected) without JLab data all are 1 s limit PDG best fit SLAC/ Prescott Qweak in Hall C (2010-): another factor of 5 improvement in knowledge of C 1q, New Physics scale from 0.9 to 2 TeV 1 H + e  e’ + p

26. 26 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Parity Violation in Deep Inelastic Scattering For an isoscalar target ( 2 H), structure functions largely simplifies: 0 1 at high x PVDIS: Only way to measure C 2q

27. 27 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PVDIS at 6 GeV (JLab E08-011) 100uA, 90% polarized beam, 20-cm LD2 target Scaler-based fast counting DAQ specifically built to accommodate the 500kHz DIS rate with 10 4 pion rejection

28. 28 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PVDIS at 6 GeV (JLab E08-011) Q 2 =1.1 Q 2 =1.9 Ran in Oct-Dec 2009, measured A d at Q 2 =1.1 and 1.9 GeV 2 to 3% and 4% (stat.), resp. Systematics dominated by beam polarization (2%). Data being analyzed, may finish by late 2011. spokespeople: R. Michaels, P.E. Reimer ，郑晓超 Grad students: 邓晓燕 (UVa M.A.), 王殿成 (UVa), 潘凯 (MIT) Postdoc: Ramesh Subedi Statistical quality of data:

29. 29 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan E08-011 Projected Results on C 2q with recent PVES data and Qweak with JLab 6 GeV all are 1 s limit SAMPLE SLAC/ Prescott C 2u +C 2d 1.25 1.5 1.75 1.0 0.75 0.5 0.25 0 -0.5 -0.75 C 2u -C 2d - 0.20.40.20- 0.4 PVDIS @6GeV: potential to improve C 2 q by factor of six if hadronic effects are small.

30. 30 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PVDIS at Higher Precision – Hadronic Physics Study Sensitivity will be further enhanced if u+d falls off more rapidly than  u-  d as x  1 u-d mass difference EM effects Direct observation of parton-level CSV would be very exciting! Important implications for high energy collider pdfs Could explain significant portion of the NuTeV anomaly For A PV in electron- 2 H DIS: CSV Higher Twist (non-perturbative nature of strong interactions)

31. 31 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Strategy: requires precise kinematics and broad range xyQ2Q2 New Physics noyesno CSV yesno Higher Twist yesnoyes Fit data to: Coherent PVDIS Program with SoLID @ 11 GeV “SoLID” spectrometer

32. 32 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Coherent PVDIS Program with SoLID @ 11 GeV figure from K. Kumar, Seattle 2009 EIC Workshop EW talks Error bar σ A /A (%) shown at center of bins in Q 2, x 4 months at 11 GeV 2 months at 6.6 GeV

33. 33 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan SAMPLE R. Young ( combined ) all are 1 s limit PVDIS@11 GeV with SoLID: potential to improve C 2q knowledge by another order of magnitude and better separation from hadronic effects. Knowledge on C 1,2q with Projected JLab 12 GeV Results C 2u -C 2d C 2u +C 2d

34. 34 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan N  ee ~ 25 TeV JLab Møller LHC New Contact Interactions Møller Parity-Violating Experiment: New Physics Reach (a large installation experiment with 11 GeV beam energy) Czarnecki and Marciano (2000) Erler and Ramsey-Musolf (2004) Expected precision comparable to the two most precise measurements from colliders, but at lower energy. No other experiment with comparable precision in the forseeable future! 12 GeV 6 GeV

35. 35 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Summary and Perspectives Recent Results: Program on nucleon strange form factors now concluded: G S E,M < a few percents of G P E,M at all Q 2 studied; PREX provided the first results on the neutron skin of heavy nuclei, follow-up measurement proposed Future: PVDIS @ 6 GeV completed, results on C 2q coming soon Qweak ongoing, best results on C 1q expected New “construction” experiments at JLab 12 GeV: PVDIS @ 11 GeV will provide sensitivity to Standard Model test, observation of CSV, and the higher twist effects Moller @ 11 GeV Many thanks to K. Paschke, D. Armstrong, R. Michaels, P. Souder for helping me to put these slides together.

36. 36 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Backup Slides

37. 37 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan SoLID Spectrometer Baffles GEM’s Gas CerenkovShashlyk Calorimeter ANL design JLab/UVA prototype Babar Solenoid International Collaborators: China (Gem’s) Italy (Gem’s) Germany (Moller pol.)

38. 38 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PVDIS on the Proton: d/u at High x Deuteron analysis has large nuclear corrections (Yellow) A PV for the proton has no such corrections (complementary to BONUS) The challenge is to get statistical and systematic errors ~ 2% 3-month run

39. 39 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Beyond Strangeness: Parity-Violating Electron Scattering as a Standard Model Test

40. 40 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PV-A4: Forward angle (MAMI) Q 2 (GeV 2 ) APV ± stat ± syst (ppm) G E s + η G M s 0.230 -5.44 ± 0.54 ± 0.26G E s + 0.225 G M s = 0.039 ± 0.034 0.110-1.36 ± 0.29 ± 0.13G E s + 0.106 G M s = 0.071 ± 0.036 Counting – fast energy histograms At Q 2 =~0.1 GeV 2, G s < few percent of G p all low Q 2 data

41. 41 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan “Parity Quality” of JLab polarized beam Beam Parameter HAPPEx-IHAPPEx-IIPREX Charge asymmetry< 0.1 ppm0.41 ppm200 ppb Position difference -11±2.3 nm, -10±1.0 nm 0.56±0.53 nm, 1.69±0.83 nm 2 nm angle difference 0.2±0.6 nrad, 3±0.2 nrad -0.26±0.24 nrad, 0.21±0.25 nrad 1 nrad Energy difference -4±1 ppb 0.2ppb (0.6 eV)1 eV Total correction-0.02 ± 0.02 ppm0.08 ± 0.03 ppm HAPPEx-II (2005): superlattice (P B >85%) 35  A ee PREX (2010): superlattice (P B >85%) 50-100  A HAPPEx-I (1999): strained GaAs (P B ~69%) 40  A beam current High “parity-quality”, negligible uncertainties due to beam; Most of 6 GeV experiments measured strange quark contribution to proton form factors: less than 5% to G E p and less than 20% to G M p

42. 42 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan JLab 6 GeV Experiment 08-011 100-105  A, 6 GeV, 87% polarized beam on a 20-cm LD2 target; Two Hall A High Resolution Spectrometers detect scattered electrons; Measured PV asymmetry A d at Q 2 =1.10 and 1.90 GeV 2 to 3 and 4%(stat.), respectively. A d at Q 2 =1.10 will set a limit on the higher twist effects; If HT is small, can extract 2C 2u -C 2d from A d at Q 2 =1.90 to ±0.05-0.06 (or with reduced precision if higher twists are unexpectedly large) Co-spokesperson & contact: X. Zheng Co-spokesperson: P.E. Reimer, R. Michaels (Hall-A Collaboration Experiment, approved by PAC27; Re-approved by PAC33 for 32 days, rated A-; Ran Nov-Dec 2009)

43. 43 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PV DIS and Other SM Test Experiments E158/Moller (SLAC) NuTeV (FNAL)Atomic PV PVDIS (JLab) Qweak (JLab) 2 (2C 1u +C 1d ) Coherent quarks in the proton Purely leptonic Weak CC and NC difference Nuclear structure? Other hadronic effects? Coherent Quarks in the Nucleus - 376C 1u - 422C 1d Nuclear structure? (2C 1u -C 1d )+Y(2C 2u -C 2d ) Isoscalar quark scattering Cartoons borrowed from R. Arnold (UMass) Different Experiments Probe Different Parts of Lagrangian, PVDIS is the only one accessing C 2q

44. 44 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Hall A large acceptance “solenoid” device: PR09-012 Measure A d to 1% for a wide range of (x,Q 2,y), clean separation of New Physics (via C 2q and sin 2  W ), HT and CSV possible; Extract d/u at large x from PVDIS on a proton target, free of nuclear effects; Other hadronic physics study possible: A 1 n at large x, Semi-inclusive DIS. Higher precision, possibly sensitive to 1) New Physics beyond the SM; 2) Charge Symmetry Violation (CSV) Two approaches: Hall C “baseline” SHMS+HMS: PR12-07-102 (P.E. Reimer, X-C. Z, K. Paschke, 1% on A d, extraction of C 2q, sin 2  W (if higher-twists and CSV are negligible); PVDIS Program at JLab 12 GeV (conditionally approved)

45. 45 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan N  ee ~ 25 TeV JLab Møller LHC New Contact Interactions Møller Parity-Violating Experiment: New Physics Reach (example of large installation experiment with 11 GeV beam energy) A FB (b) measures product of e- and b-Z couplings A LR (had) measures purely the e-Z couplings Proposed A PV (b) measures purely the e-Z couplings at a different energy scale Not “just another measurement” of sin 2 (  w )

46. 46 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Projected PVDIS Measurement with SOLID@11 GeVSOLID@11 figure from K. Kumar, Seattle 2009 EIC Workshop EW talks

47. 47 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan ONGOING CONSTRUCTION EFFORTS Hall D - Central Drift Chamber Endplates @ CMU Hall C – Drift Chambers @ HU & Scintillators @ JMU Hall B - Drift Chambers @ JLab, ODU and ISU 12 GeV Groundbreaking (Apr2010) Hall D Concrete Wall Erection (Apr 2009)

48. 48 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Backup Slides

49. 49 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Staff: ~650 User community: ~1300 A CB

50. 50 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Beam was first delivered in 10/95 In full operation for ~13 years (since 11/97); 283 PRL and PL to date: ½ expt, ½ theory) 334 PhDs to date and 249 in progress (~1/3 of US PhDs in Nuclear Physics)

51. 51 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Three Experimental Halls (Present) Hall A: pair of high resolution spectrometers (HRS), E' up to 4 GeV/c, = 7 msr luminosity up to 10 39 cm -2 s -1 Hall C: High Momentum (HMS and Short-Orbit Spectrometers (SOS) luminosity up to 10 39 cm -2 s -1 Hall B: CEBAF Large Acceptance Spectrometer (CLAS) luminosity up to 10 34 cm -2 s -1

52. 52 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Measurement of P-V Asymmetries e.g. 5% Statistical Precision on 1 ppm -> requires 4x1014 counts Rapid Helicity Flip: Measure the asymmetry at 10-4 level, 10 million times  High luminosity: thick targets, high beam current  Control noise (target, electronics)  High beam polarization and rapid flip

53. 53 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Medium & High Energy Physics Facilities for Lepton Scattering High luminosity, yet “continuous” polarized beam makes JLab an unique facility. ~ns: “continuous” >>ns: “pulsed”

54. 54 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan PREX & Neutron Stars Crab Pulsar ( C.J. Horowitz, J. Piekarewicz ) R calibrates EOS of Neutron Rich Matter Combine PREX R with Obs. Neutron Star Radii Some Neutron Stars seem too Cold N N Crust Thickness Explain Glitches in Pulsar Frequency ? Strange star ? Quark Star ? Cooling by neutrino emission (URCA) 0.2 fm URCA probable, else not Phase Transition to “Exotic” Core ?

55. 55 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Measured Asymmetry Weak Density at one Q 2 Neutron Density at one Q 2 Correct for Coulomb Distortions Small Corrections for G n E G s E MEC Assume Surface Thickness Good to 25% (MFT) Atomic Parity Violation Mean Field & Other Models Neutron Stars R n PREX Physics Output Slide adapted from C. Horowitz

56. 56 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Deuterium: PVDIS Asymmetries A PV = + + g: coupling constant,  : mass limit, h A q : effective coefficient New physics sensitivity: Sensitive to: Z' searches, compositeness, leptoquarks Mass limit:

57. 57 X. Zheng, University of Virginia, Talk at OCPA7, August 1-5, Kaotsiung, Taiwan Plan View of the Spectrometer BaBar Solenoid?