Jefferson Lab, latest results and the 12GeV Upgrade

1. Jefferson Lab, latest results and the 12GeV Upgrade Add new hall CHL-2 Enhance equipment in existing halls Ken Livingston, University of Glasgow. Nuclear Physics UK Community Meeting Cosener’s House 11th & 12th June 2009 CEBAF, Jefferson Lab, Virginia. 6 GeV racetrack configuration. > 200uA to 3 experimental areas CLAS Spectrometer (Hall B) Polarisation observables in strangeness production BigBite (Hall A)Gen - neutron electric form factor “Highest priority” STFC Programmatic review Jlab 12GeV Upgrade $310M Highest priority in the DoE/NSF NSAC long range plan Approval to begin construction phase (CD3) in 2008. CLAS 12 (Hall B) Generalised Parton Distributions (GPDs) Quasi-Real photon beam Super BigBite (Hall A) Form factors, compton scattering GlueX (Hall D) QCD exotics • > 1000 scientists, 200 institutes, 20 countries • No annual costs, No running costs. • We provide expertise and additional hardware. • Value for money. • UK groups – Glasgow, Edinburgh (UWS ?)

2. CLAS - Missing resonances and resonance spectroscopy Particle Data Group star ratings • Constituent quark models predict many resonances. • Some missing – undetected or wrongly predicted ? • Most data from pion beam expts. • Coupling to photon, particularly strange channels. • Cross sections not enough to separate broad, overlapping resonances. • Angular distributions and polarisation observables. • Ideal – tagged, polarized photons at CLAS

3. Linear Polarisation  Glasgow, K.Livingston Circular polarisation  → Y +  Nucleon recoil polarimiter x Longitudinally polarised nucleon targets  Transverse polarised nucleon targets  Hyperons are “self analysing”  Polarisation observables • + N→ N + m Strangeness production Glasgow D. Ireland, K.Livingston Single pion production Edinburgh D.Watts

4. Polarisation observables in pseudoscalar meson production 4 Complex amplitudes - 16 real polarisation observables. A complete measurement from 8 carefully chosen observables. Observable g target recoil I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95 347 (1975).

5. Polarization observables - a simple example, S • Systematics of detector acceptance cancel out. • Only need to know Plin, the degree of linear polarization.

6. Preliminary results - K+L and K+S0Craig Paterson, Glasgow gp-> K+L -> K+pp-gp-> K+S0 -> K+Lg -> K+pp-g Single polarization observablesS Photon asymmetryP Recoil polarization (induced pol. along y)T Target asymmetryDouble polarization observablesOx Polarization transfer along xOz Polarization transfer along z LS0 figure by R.Schumacher, CMU

7. Preliminary results - K+L Craig Paterson, Glasgow Photon Asymmetry • Results compared with previous results from LEPS • 6, 100MeV Energy bins 1550 -> 2050MeV • More bins for our data Increase the angular coverage to backward angles PRELIMINARY

8. Preliminary results - K+L Double polarization observable Ox Results compared with Regge-Plus-Resonance model from Gent group • -Large Polarization transfers • Some evidence for an important role for missing D13(1900) state • Poor agreement at low energy • Huge addition (> 500 points) to the database of measurements for constraining theory. PRELIMINARY • Summary: polarisation observables, towards a complete measurement and missing resonances. • New, precision measurements on p, eta, strangeness, single and double polarization observables in progress. • Data taking with polarised target will be completed in spring 2010. • First ever “complete measurement” on K Lambda, K Sigma soon. • New, high precision range of polarisation FIX THIS TEXT

9. Hall A – BigBite and Neutron Electric Form Factor J. Annand, D. Hamilton, Glasgow Gen - the charge distribution inside the neutron CQM - Miller • Hall A • 2 High resolution spectrometers • Specific kinematics • High current > 30uA • extras .... Electron arm pQCD Target q(2q) DSE VMD Neutron arm Galster FSI correction not applied Dump

10. Hall A @ 12GeV Super BigBite J. Annand, D. Hamilton, Glasgow • Super BigBite • Modular spectrometer / polarimiter • Option of RICH from Hermes for Kaons • 4 A rated proposals on Form Factors GEMs • - Magnet: 48D48 - 46 cm gap, 2.5 Tm • - Solid angle is 70 msr at angle 15° • - GEM chambers with 70 μm resolution • - Momentum resolution is 0.5% for 5 GeV/c • Angular resolution is 0.3 mrad

11. Last 50 years Last 40 years Last 10 years ? Structure functions, quark longitudinal momentum & spin distributions Proton form factors transverse charge & current densities. Correlated quark momentum and helicity distributions in transverse space - GPDs CLAS 12 Generalised Parton Distributions (GPDs) R.Kaiser, B.Seitz, Glasgow

12. CLAS 12 GPDs via DVCS • HERMES now complete. • CLAS 12 optimised for DVCS. • Polarised targets, Asymmetry measurement • High luminosity to reach high XB • Glasgow GPD programme will move from HERMES -> CLAS12 (spokepsersons on 3 approved proposals) • Example of the provision of expertise.

13. CLAS12 EC Cerenkov Drift Chambers TOF Cerenkov Torus Central Detector Beamline IEC G.Rosner – CLAS12 steering committee B. Seitz, M. Hoek, uChan PMT for CTOF Luminosity > 1035cm-2s-1

14. Quasi Real Photon Beam Calorimiter to tag Q2~0 electrons Linearly polarized parasitic K. Livingston, D.Ireland, Glasgow D.Watts, D. Glazier, Edinburgh With Jlab, + INFN, Italy. Existing tagging spectrometer can’t tag beam > 6GeV

15. GlueX exotic hybrid mesons Flux tube model • Provides a framework to understand gluonic excitations. • Conventional mesons have the color flux tube in the ground state. When the flux tube is excited hybrid mesons emerge. For static quarks the excitation level above the ground state is ~1 GeV. • The excitation of the flux tube, when combined with the quarks, can lead to spin-parity quantum numbers that cannot be obtained in the quark model (JPC - exotics). • The decay of hybrid mesons leads to complex final states. JPC = 0+-, 1-+, 2+-

16. Hall-D, GlueX ++ Lead Glass Detector Barrel Calorimeter Coherent Bremsstrahlung Photon Beam Solenoid Time of Flight Note that tagger is 80 m upstream of detector Tracking Cerenkov Counter Target • Tagger Magnet design, G. Yang, Glasgow • Coherent brem facility and diamonds – K.Livingston, G.Yang, Glasgow Electron Beam from CEBAF • Hall D additional physics potential. High linear polarization, high intensity 2-6GeV. • Development of recoil polarimiter – D.Watts, Edinburgh.

17. Conclusion • Jefferson Lab is the world’s leading facility for hardon physics. • UK Groups (Glasgow, Edinburgh) have leading role in current programme. • High quality measurements from Hall A, Hall B We are here NSAC Long Range Plan (2007) Recommendation 1 of 4 We recommend the completion of the 12 GeV Upgrade at Jefferson Lab. - It will enable three-dimensional imaging of the nucleon, revealing hidden aspects of its internal dynamics. • It will complete our understanding of the transition between the hadronic and quark/gluon descriptions of nuclei. • It will test definitively the existence of exotic hadrons, long-predicted by QCD as arising from quark confinement. • It will provide low-energy probes of physics beyond the Standard Model complementing anticipated measurements at the highest accessible energy scales. 2014 • UK Groups have opportunity, at very low cost, to participate

18. CLAS coherent bremsstrahlung facility • Tagging spectrometer with high rate, good energy and timing resolution • High precision goniometer (GWU) • High quality, thin diamond (Glasgow) • Tight photon beam collimation (ISU) • Polarimetry Photon energy P > 90% Peak > 90% pol. “A device called a goniometer tilts the diamond, much like a lady turning her hand to admire the sparkle of a new ring.” - JLAB On Target Magazine

19. Measurements with photon beam profile detectorD. Glazier, Glasgow 1st Measurement of 2D photon enhancement for coherent bremsstrahlung (MAMI,Mainz) paper in preparation below peak coherent peak above peak Coherent peak at 300Mev, MAMI electron beam energy 855MeV • Good agreement with coherent bremstrahlung calculations • Improvements in incoherent component, collimation + multiple scattering. • No evidence of high energy photons from quasi channeling. • Investigation of 2D strip detector for polarimetry

20. g8b preliminary results - K+L • K+LPhoton Asymmetry, S, extracted from cos(2f) fit to azimuthal kaon distribution • Fits shown for 1 energy bin • 340 (20E, 17q) kinematic bins • Almost full angular coverage

21. g8b preliminary results - K+S0 • Results compared with previous results from GRAAL • 7, 50MeV Energy bins • 1175 -> 1475MeV • Good agreement with previous results PRELIMINARY

22. g8b preliminary results - K+S0 • Results compared with previous results from LEPS • 6, 100MeV Energy bins • 1550 -> 2050MeV • More bins for our data!!! Increase the angular coverage to backward angles PRELIMINARY

23. Peak > 90% pol. PRELIMINARY K.Livingston, Glasgow J.Santoro, CUA Polarimetry: from pair (e+,e-) productionH.Schmieden, Bonn • Well described by QED, but experimentally difficult – small opening angle e+ e- • Pair production simulations by Kharkov group • Polarimeter built and tested at Sping8, recently tested at Jlab • Polarimeter to be based on Jlab design • Microstrip detectors, or pixel detectors (Atlas group) • Bonn student completed 10 months exchange in Glasgow now to be full time in Bonn.

24. Polarimetry: from hadronic reactionR. Beck, Mainz -> Bonn Use reaction with a known photon asymmetry • Can be high statistics • Very good relative monitor of polarization • Combined beam, target polarization. • Non-indpendent – depends on specific expt • Need very good systematics or calibration • Awaiting MAMI polarized target and polarised photon beam in 2nd half of 2007 • Recent preliminary results from JLab (g8b)‏ • Proton target • Back to back charge particles in Start Counter • Atomic or hardonic ? • Asymmetry from ~20mins DAQ data • Constant with E from 1.3GeV – 1.9GeV

25. g8b: July 2005 Polarized photon energy range: 1.3 – 2.1 GeV Events (single charged particle in CLAS): 10 billion preliminary results:p0p, p+n.Mike Dugger, ASU CLAS data SAID High statistics. Good agreement with previous measurement. Data set extends to photon energy up to 2.1GeV

26. g8b preliminary results:hp, h’pMike Dugger, ASU SAID MAID Nakayama and Haberzettl effective lagrangian model High stats for h. Good agreement with previous measurements. Data set extends to photon energy up to 2.1GeV First measurement of S for h’ 2 Eg bins one for coh peak at 1.9 and 2.1GeV

27. g8b preliminary results - K+L • Results compared with previous results from GRAAL • 7, 50MeV Energy bins • 1175 -> 1475MeV • Good agreement with previous results PRELIMINARY

28. g8b preliminary results - K+L Ox/Ozextracted from fit to 2d asymmetry T Target asymmetry from 2d asymmetry (not shown) P Recoil pol. from acceptance corrected proton dist. P Recoil pol. g8b GRAAL CLAS J.W.C. McNabb, et al. (CLAS) Phys. Rev. C 69, 042201(R) (2004).

29. g13 meson photoproduction, polarized photons on LD2 gn (p)-> p+p (p) Daria Sokhan, Edinburgh • g13a circularly polarized photons • ~2GeV, ~2.6GeV electron beam • ~2 months beamtime • g13b linearly polarized photons • 1.3, 1.5, 1.7, 1.9, 2.1, 2.3 GeV coh peak • ~ 2months beamtime • Single charge particle trigger • ~7kHz event rate PRELIMINARY MAID SAID Previous data

30. g13 meson photoproduction, polarized photons on LD2 gn (p)-> K0sL0(p) Neil Hassall, Glasgow gp (n)-> K+L0 (n) Russell Johnstone, Glasgow See talk in Hadron Spectroscopy session PRELIMINARY 1st results photon asymmetry S Cosqcm (-0.8 - +0.8) Each plot is 50MeV photon energy bin 1050-2450MeV

31. g9 FROST – FROzen Spin Target Meson photoproduction with linearly and circularly polarized photons on polarized target E02-112: γp→KY (K+Λ, K+Σ0, K0Σ+)‏ E03-105/E04-102: γp→π0p, π+n E05-012: γp→ηp E06-013: γp→π+π-p g9a running conditions November 3, 2007– February 12, 2008 Longitudianally polarized target Circularly and linearly polarized photon beam 0.5-2.4 GeV Trigger: at least one charged particle in CLAS Target Pol > 80%, Relaxation time > 1600hrs – better that design goals

32. g9aFROST sample analysis of gpp+nEugene Pasyuk, ASU Helicity asymmetry E • Select p+ applying cut on b vs. p • Vertex cuts • Select missing neutron Raw asymmetry butanol 12C CH2 butanol 12C CH2 Preliminary Based on ~2% of statistics

33. g8b data. g + p → p+ n with (n,p) scatter (detect p+p) q Mx(gp→p++X) Angle between Pncalc and Ppmeasured K.Livingston Recoil polarimetry possibilities ? n(q,f) =no(q){1+A(q)[Pycos(f)–Pxsin(f)] - How to do this for 4p detector x and y (transverse) components of nucleon polarisation Nucleon polarimeter for CB@MAMI, D. Watts, Edinburgh Graphite p q n g p+ Start counter

34. g8b preliminary results - K+L Full lamba polarization ? With circularly polarized photons – “fully polarized lambda” R. Bradford et al. (The CLAS Collaboration), Phys. Rev. C 75, 035205 (2007). - Full polarization at forward angles - Not repeated over full kinematic range - More relations can be tested PRELIMINARY (P2 + Ox2+Oz2)1/2

35. g8b (lin. pol. on LH2) cooking complete, analysis well developed • Photon asymmetries for p0p,p+n, h, h’ KL, KS: prelim. results. • P, T Ox, Oz for KL, KS: • g13 (lin., circ. pol on LD2) cooking in progress, analysis beginning • Some very preliminary results for photon asymmetry. • g9 (lin, circ pol on L/T pol butanol) cooking about to begin • Circularly polarized photon beam on longitudinally polarized target • E P, Lx/Lz, Cx/Cz • Linearly polarized photon beam on longitudinally polarized target • , G, P, (Tx/Tz) Ox/Oz • Circularly polarized photon beam on transversely polarized target • T, F, P, Tx/Tz, Cx/Cz • Linearly polarized photon beam on transversely polarized target • , H, T, P, (Lx/Lz)‏ • Upon completion of g9b for the first time we will have complete set of observables in Kaon photoproduction and nearly complete for all other mesons, which will allow model independent extraction of the amplitude for subsequent extraction of baryon resonances and their properties. (E. Pasyuk). • eg6 4He target, Bonus detector coherent meson production. (S.Stepanyan talk on Friday) scheduled 2009 • HDice (A.Sandorfi, F.Klein) Polarized HD target –further extesion of polarization observables scheduled 2010 • CLAS12 • Tagger will only tag up to 6GeV primary beam • Development of Quasi real photon beam (Q2~0) S.Stepanya, R.DeVita, M. Battaglieri • Post target tagger – linearly polarized • High rates scheduled 2010

36. Jefferson Lab and the 12GeV Upgrade Ken Livingston, University of Glasgow Nuclear Physics UK Community Meeting Cosener’s House 11th & 12th June 2009 • Overview of Jefferson Lab and the 12 GeV upgade programme • CLAS Spectrometer (Hall B) • Polarisation observables in strangeness production • CLAS12 • BigBite (Hall A) • Gen - neutron electric form factor • Super BigBite • GlueX (Hall D)