CHL-2 Enhance equipment in existing halls Add new hall Jefferson Lab, latest results and the 12GeV Upgrade Ken Livingston, University of Glasgow. Nuclear Physics UK Community Meeting Coseners House 11 th & 12 th 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) G en - 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 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 ?)

CLAS - Missing resonances and resonance spectroscopy 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 Particle Data Group star ratings

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

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

Polarization observables - a simple example, Systematics of detector acceptance cancel out. Only need to know P lin, the degree of linear polarization.

Preliminary results - and Craig Paterson, Glasgow p p p p Single polarization observables Photon asymmetry P Recoil polarization (induced pol. along y) T Target asymmetry Double polarization observables O x Polarization transfer along x O z Polarization transfer along z figure by R.Schumacher, CMU

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

Preliminary results - Double polarization observable O x Results compared with Regge-Plus-Resonance model from Gent group - Large Polarization transfers - Some evidence for an important role for missing D 13 (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 First ever complete measurement on K Lambda, K Sigma soon. New, high precision range of polarisation FIX THIS TEXT

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

Hall 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: 48D cm gap, 2.5 Tm - Solid angle is 70 msr at angle 15° - GEM chambers with 70 m resolution - Momentum resolution is 0.5% for 5 GeV/c - Angular resolution is 0.3 mrad

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

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

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

Existing tagging spectrometer cant tag beam > 6GeV Quasi Real Photon Beam Calorimiter to tag Q 2 ~0 electrons Linearly polarized parasitic K. Livingston, D.Ireland, Glasgow D.Watts, D. Glazier, Edinburgh With Jlab, + INFN, Italy.

GlueX exotic hybrid mesons J PC = 0 +-, 1 -+, 2 +- 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 (J PC - exotics). –The decay of hybrid mesons leads to complex final states.

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

Conclusion Jefferson Lab is the worlds leading facility for hardon physics. UK Groups (Glasgow, Edinburgh) have leading role in current programme. High quality measurements from Hall A, Hall B 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. UK Groups have opportunity, at very low cost, to participate We are here 2014

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 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 Peak > 90% pol. CLAS coherent bremsstrahlung facility Photon energy P > 90%

Measurements with photon beam profile detector D. Glazier, Glasgow 1 st Measurement of 2D photon enhancement for coherent bremsstrahlung (MAMI,Mainz) paper in preparation 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 Coherent peak at 300Mev, MAMI electron beam energy 855MeV below peakcoherent peakabove peak

Photon Asymmetry,, extracted from cos(2 ) fit to azimuthal kaon distribution Fits shown for 1 energy bin 340 (20E, 17 ) kinematic bins Almost full angular coverage g8b preliminary results -

Results compared with previous results from GRAAL 7, 50MeV Energy bins > 1475MeV Good agreement with previous results PRELIMINARY

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

Pair production simulations by Kharkov group Polarimeter built and tested at Sping8, recently tested at Jlab e+e-e+e- 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. Polarimetry: from pair (e +,e - ) production H.Schmieden, Bonn Well described by QED, but experimentally difficult – small opening angle PRELIMINARY J.Santoro, CUA Peak > 90% pol. K.Livingston, Glasgow

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 2 nd half of 2007 Polarimetry: from hadronic reaction R. Beck, Mainz -> Bonn 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

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

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

g8b preliminary results - Results compared with previous results from GRAAL 7, 50MeV Energy bins > 1475MeV Good agreement with previous results PRELIMINARY

g8b preliminary results - O x /O z extracted from fit to 2d asymmetry T Target asymmetry from 2d asymmetry (not shown) P Recoil pol. from acceptance corrected proton dist. g8b GRAAL CLAS J.W.C. McNabb, et al. (CLAS) Phys. Rev. C 69, (R) (2004). P Recoil pol.

g13 meson photoproduction, polarized photons on LD 2 n (p) p p Daria Sokhan, Edinburgh MAID SAID Previous data PRELIMINARY 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

g13 meson photoproduction, polarized photons on LD 2 p (n) n Russell Johnstone, Glasgow See talk in Hadron Spectroscopy session n (p) s p Neil Hassall, Glasgow PRELIMINARY 1 st results Cos cm ( ) Each plot is 50MeV photon energy bin MeV photon asymmetry

Meson photoproduction with linearly and circularly polarized photons on polarized target E02-112: γpKY (K + Λ, K + Σ 0, K 0 Σ + ) E03-105/E04-102: γpπ 0 p, π + n E05-012: γpηp E06-013: γpπ + π - p g9a running conditions November 3, 2007– February 12, 2008 Longitudianally polarized target Circularly and linearly polarized photon beam GeV Trigger: at least one charged particle in CLAS Target Pol > 80%, Relaxation time > 1600hrs – better that design goals g9 FROST – FROzen Spin Target

butanol 12 CCH 2 Helicity asymmetry E Raw asymmetry g9aFROST sample analysis of gp + n Eugene Pasyuk, ASU Select + applying cut on vs. p Vertex cuts Select missing neutron Based on ~2% of statistics Preliminary butanol 12 CCH 2

Recoil polarimetry possibilities ? g8b data + p + n with (n,p) scatter (detect + p) M x ( p + +X) + n p Start counter K.Livingston Angle between P n calc and P p measured x and y (transverse) components of nucleon polarisation n( ) =n o ( ){1+A( )[P y cos( )–P x sin( )] - How to do this for 4 detector Nucleon polarimeter for D. Watts, Edinburgh Graphite

g8b preliminary results - Full lamba polarization ? With circularly polarized photons – fully polarized lambda R. Bradford et al. (The CLAS Collaboration), Phys. Rev. C 75, (2007). - Full polarization at forward angles - Not repeated over full kinematic range - More relations can be tested PRELIMINARY (P 2 + O x 2 +O z 2 ) 1/2

scheduled 2010 g8b (lin. pol. on LH2) cooking complete, analysis well developed Photon asymmetries for p, n,,, : prelim. results. P, T Ox, Oz for, : 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 (Q 2 ~0) S.Stepanya, R.DeVita, M. Battaglieri Post target tagger – linearly polarized High rates

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