Spin Based Physics at Jefferson Lab Hugh Montgomery

1. Spin Based Physics at Jefferson Lab Hugh Montgomery October 10, 2008

2. Outline • State-of-the-art technologies •   Spin physics at Jefferson Laboratory • The first ten years • The remaining “6 GeV” program • Jlab 12 GeV Upgrade • ELIC • Summary

3. Spin, Current, and Beam Delivery @CEBAF Under development <0.5% Atomic Beam Polarimeter (Hall A) <1% Compton Polarimeter (Hall C)

4. Polarized Targets at JLab Hall B: eg1 Dynamically polarized NH3 ND3, Q2 evolution of Nucleon Spin Structure, DVCS Hall A: 3He GEn, SSAs Transversity Hall C: Dynamically polarized, NH3 ND3 GEn, SANE, g1p, g1d Hall B: FROST Frozen Spin Target, Butanol “Missing” N* Search. HDIce from BNL under development: Polarized neutron target for N* expts.

5. Highlights: first 10 Years of Physics at JLab • QCD and the Structure of Hadrons • Discovery of unexpected behavior of GEp ; Measurement of GEn • Strangeness content of the proton • The deformation of  and N* transition form factors • Spin dependent structure functions: Bjorken & GDH sum rule; g1n; |∆ G| • Measurement of the pion form factor • Exploration of duality, pQCD counting rules, color transparency • Initial exploration of Generalized Parton Distributions (GPDs)towards mapping of angular momentum in the proton • Nuclei: From Structure to Exploding Stars • New information on correlations in nuclei and the role of the tensor force • Studies of hypernuclei – better than 400keV resolution • In Search of the New Standard Model • factor 5 increase in precision of Standard Model couplings

6. Jefferson Lab – Spin Structure Functions g1(x,Q2) World data on the proton including Jlab covering the resonance region and overlapping with the DIS domain Similar coverage for the Deuteron Enormous contribution towards understanding the spin of and in the nucleon. Halved the uncertainties in the parton distribution functions.

7. Preliminary High-Q2 results for GEn • GEn at 1.7 GeV2 is well above GGalster. • GEnat 3.4 GeV2 is closer to GGalster and far below CQM and GPD • Final accuracy for 3.4 GeV2 expected to improved by factor 1.5 • Next release will be the result at 2.5 GeV2

8. Science Remaining for CEBAF@6 GeV? • Completion of data-taking for milestone-related physics • Baryon spectroscopy (FROzen Spin Target and HDIce target data) • DVCS (CLAS Phase II and Hall A separation of BHDVCS and DVCS2) • Structure function moments (SANE, d2n) • ….. • Important new data on: • Strange quark distributions (HAPPEx III) • Hypernuclear spectroscopy • Correlations (4He(e,e’pN) data extended) • Dispersive effects in electron scattering [(e+,e+) vs (e-,e-)] • Transversity • ….. • Unique new experimental directions: • PREx (rms radius of neutron dist. for nuclear structure, astrophysics, and atomic PV Standard Model tests) • QWeak(Weak charge of the proton for a Standard Model Test) • Measurements in new areas of research that will be a focus of science with the 12 GeV Upgrade, such as: • Single spin asymmetries • DVCS w/ Longitudinally polarized target • PVDIS, …..

9. Deep Virtual Compton Scattering : Gen. Parton Dists? • Three A-rated experiments combined allow the separation of Generalized Parton Distributions. • Hall A Experiment will separate the Bethe-Heitler from the Deep Compton • Hall B E1-DVCS and EG1-DVCS are scheduled to run in 2008/2009 and use polarized electron beams and longitudinally polarized proton target. • HD-DVCS is conditionally approved (relying on the operation of the HD-Ice target with electron beams) will use a transversely polarized proton (and deuterium) target.

10. Weak Couplings All Data & Fits Plotted at 1σ Isoscalar weak charge Standard Model Prediction HAPPEx: H, He G0: H, PVA4: H SAMPLE: H, D Q-weak expected precision Isovector weak charge

11. TJNAF E06-002: PREX A Clean Measurement of the Neutron Skin in 208Pb Q2~0.008 GeV2, E = 1 GeV, Z0 : Clean Probe Couples Mainly to Neutrons δ(APV) ~ ± 3% δ(Rn) ~ ±1% Subject of Aug 08 JLab workshop that attracted 70 experts from many different fields • Physics Implications • Nuclear Equation of State • Neutron stars • Size and density • Crust • Cooling • Heavy Ion Collisions • Atomic Parity Violation ( Dany Page )

12. 12 GeV Upgrade Current Status • Technical Status • R&D 98% complete • Overall PED 76% complete (Civil design 100% complete) • 18 major procurement packages issued • bid packages under review for 5 major procurements • 2009-2014 Construction • Is starting FY2009 • Accelerator shutdown – May 2011 through Oct 2011 (6 months) • Accelerator shutdown start mid-May 2012 ; commissioning mid-May 2013 • 2013-2015 Hall Pre-Ops (beam commissioning) • Hall A commissioning start ~October 2013 • Hall D commissioning start ~April 2014 • Halls B and C commissioning start ~October 2014

13. 12 GeV Upgrade New Hall CHL-2 Maintain capability to deliver lower pass beam energies Enhanced capabilities in existing Halls

14. 12 GeV Upgrade

15. Measuring High-x Structure Functions REQUIRES: • High beam polarization • High electron current • High target polarization • Large solid angle spectrometers 12 GeV will access the regime (x > 0.3), where valence quarks dominate

16. Unraveling the Quark WNC Couplings V A A V 12 GeV: (2C2u-C2d)=0.01 PDG: -0.08 ± 0.24 Theory: +0.0986 Vector quark couplings Axial-vector quark couplings

17. Møller Parity-Violating Experiment: New Physics Reach JLabMøller JLabMøller LHC ee ~ 25 TeV ee ~ 25 TeV New Contact Interactions New Contact Interactions Dsin2(Qw) = 0.00025  0.000008 fm  25 TeV mass scale Dsin2(Qw) = 0.00025  0.000008 fm  25 TeV mass scale LEP200 Complementary; 1-2 TeV reach Dsin2(Qw) = 0.00025  0.000008 fm  25 TeV mass scale ee ~ 15 TeV LEP200 Kurylov, Ramsey-Musolf, Su ee ~ 15 TeV Does Supersymmetry (SUSY) provide a candidate for dark matter? LHC • Lightest SUSY particle (neutralino) is stable if baryon (B) and lepton (L) numbers are conserved Complementary; 1-2 TeV reach • However, B and L need not be conserved in SUSY, leading to neutralino decay (RPV) 95% C.L. JLab 12 GeV Møller D sin2qW ~ 0.00025

18. Hall D GluEX uses polarized photons

19. Electron Ion Collider • Recommended as a generic capability by: • NSAC Long Range Report • IUPAP WG9 Working Group on world-wide nuclear facilities • Candidate Facilities with different key characteristics • LHeC at CERN • eRHIC at Brookhaven National Laboratory • ELIC – ELectron Ion Collider at Jlab • MANUEL at FAIR-GSI • Natural Extension of Jlab nuclear physics agenda • Issues • Physics Case(s) not yet broadly accepted • Cost scale is thought to be large • Collaboration with BNL • Directors to commission an advisory group to help advise prepare the case for the next NSAC Long Range Plan. Group exists, charge drafted, need date.

20. ELectronIon Collider

21. Spin with ELIC • Ring-Ring (R-R) design taking CEBAF advantage as full energy polarized injector • 12 GeV CEBAF Upgrade polarized source/injector already meets beam requirement of R-R design (0.1 mA) • Spin Capabilities • Longitudinal polarization at the IP for both beams • Transverse polarization of ions • Spin-flip of both beams • All polarizations >70% desirable • “Figure-8” ion and lepton storage rings • Ensure spin preservation and ease of spin manipulation • No spin sensitivity to energy for all species. • Luminosity of3 ·1034 cm-2s-1 (per IP, 4 IP’s) at 0.5 GHz collision frequency, with a 10σ aperture for proton and 13σ aperture for electrons

22. Explore the structure of the nucleon • Parton distribution functions • Longitudinal and transverse spin distribution functions • Generalized parton distributions • Transverse momentum distributions

23. Precisely image the sea quarks Spin-Flavor Decomposition of the Light Quark Sea u u u > Many models predict Du > 0, Dd < 0 u d | p = + + + … u u u u d d d d RHIC-Spin region No competition foreseen!

24. Jefferson Lab and Spin • The physics program thus far has been dominated by that part depending on SPIN • The remaining 6 GeV Program is dominated by SPIN • The 12 GeV Program, as far as we understand it now, is dominated by SPIN • ELIC Capabilities emphasize SPIN • At JLAB SPIN is very much an everyday tool and will likely remain so.