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Missing Resonances and Beyond

Missing Resonances and Beyond. Ken Livingston, University of Glasgow, Scotland. Nucleon resonances and complete measurements Missing nucleon resonances Jefferson Lab and the N* programme at CLAS Hyperon results and status of N* The future The Jefferson Lab 12GeV upgrade

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Missing Resonances and Beyond

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  1. Missing Resonances and Beyond Ken Livingston, University of Glasgow, Scotland • Nucleon resonances and complete measurements • Missing nucleon resonances • Jefferson Lab and the N* programme at CLAS • Hyperon results and status of N* • The future • The Jefferson Lab 12GeV upgrade • Future facilities – EIC, ESS, ELI • SCAPA

  2. Mart & Benhold, Phys. Rev. C 61 012201(R) (1999) With D13 Without D13 Missing resonances γp cross section: World Data Clear indication of resonances Broad and overlapping Below energy regime of PQCD Constituent quark models SU(6) x O(3) Eg. Forsyth & Cutkosky, Koniuk & Isgur, Capstick & Roberts Constituent quark models predict many resonances, but several missing. Are they wrongly predicted, or difficult to find experimentally? Most data is from πN scattering and single πphotoproduction. Hyperons (nucleons with strange quark) are promising (g + N -> +  and g + N -> + ) Cross sections are not enough – need angular distributions and polarization observables.

  3. Polarization observables in pseudoscalar (0-) meson production 4 Complex amplitudes: 16 real polarization observables. Complete, model independent, measurement from 8 carefully chosen observables. πN: high statistics KY recoil: self-analysing ) ( I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95 347 (1975). Systematics of detector acceptance cancel out. Only need to know Plin, the degree of linear polarization.

  4. Jefferson Lab, Virginia, USA LINAC LINAC A C B Continuous Electron Beam Accelerator Facility • E: 0.75 –6 GeV • Imax: 200mA • RF: 1499 MHz • Duty Cycle:  100% • s(E)/E: 2.5x10-5 • Polarization: 80% • Simultaneous distribution to 3 experimental Halls Injector TAGGER Experimental Halls

  5. CEBAF Large Acceptance Spectrometer Torus Magnet 6 Superconductive Coils Electromagnetic Calorimeter lead/plastic scintillator, 1296 PMTs Target +  start counter e mini-torus Drift Chamber 35,000 cells Cherenkov Counter e/ separation, 256 PMTs Time of Flight Plastic Scintillator, 684 PMTs

  6. Hall B Photon Tagger and Coherent Bremsstrahlung Eg= Ee- Ee’ 11m Ee Amorphous radiator Ee’ Ee Diamonds Need to be “perfect” monocrystals Assessment difficult and expensive  Tagger in Intregrating mode …. Could we do this at SCAPA? up to 90% linear polarization Diamond radiator

  7. → Y Nucleon recoil polarimiterx Hyperons are “self analysing”  Longitudinally polarized nucleon targets pn Transverse polarized nucleon targets pn Polarization observables at CLAS Linear Polarisation  Circular polarisation  • + N→ m Crystal Ball MAMI, D.Watts, Edinburgh.

  8. Polarization observables in g + p → K + Y(Lin Pol Beam, LH2 target) Craig Paterson, Glasgow LS0 Double polarization observablesOx Polarization transfer along xOz Polarization transfer along z Single polarization observablesS Photon asymmetryP Recoil polarization (induced pol. along y)T Target asymmetry

  9. Polarization observables in g + p → K + Y(Lin Pol Beam, LH2 target) Craig Paterson, Glasgow Photon Asymmetry g+ p → K + L Double Pol ObsCx for g+ p → K + L Good agreement with previous data. Better statistics Gent Regge + Resonance Model (Corthals et al. Phys Rev C73 2006) Data + Reggebackground (R) - - - - - - - - - R + core resonances (C) - . - . - . - . - R + C + D13(1900) __________ R + C + P11(1900) __ __ __ __ Many more bins in CM angle and Energy. Cos (θcm) K

  10. Polarization observables in g + n → K + Y(Lin Pol Beam, LD2 target) Neil Hassall, Glasgow Sergio Anefalos Pereira, INFN. Phys. Lett. B 688 (2010) 289-293 gn (p)-> K0s L0(p) gn(p)-> K0s S0(p) Edwin Munevar, GWU PRELIMINARY • Detect p- n, K+ • Σfrom p- n inv. mass PRELIMINARY 1st measurements S, P, T, Ox,Oz • CLAS Data ▲ LEPS _____ Gent RPR model

  11. Status of N* program - complete measurements PhD awarded - S. Fegan FROST 2 new students – HDIce (running now) ✔ -published, ✔- acquired, ✔- running now Each ✔ ✔ represents a future publication.

  12. Status of N* program Search for baryon states in γp➝pω➝pπ+π-(π0) • Spin density matrix elements in bins ΔW = 10 MeV, for W = 1.7–2.4 GeV in blue - blueshades. • Previous world data in red. ω production is dominated by the well known F15(1680), D13(1700) and G17(2190), and a predicted “missing” F15(2000). F15(2000)/G17(2190) M. Williams, et al. (CLAS) , Phys.Rev.C80:065209,2009 M. Williams, et al. (CLAS) , Phys.Rev.C80:065208,2009

  13. Construction of the new Hall D Upgrade of the arc magnets CHL-2 Upgrade of the instrumentation of the existing Halls The JLab 12GeV upgrade (15min) Beam Power: 1MW Beam Current: 90 µA Max Pass energy: 2.2 GeV Max Enery Hall A-C: 10.9 GeV Max Energy Hall D: 12 GeV

  14. < 6 GeV Spectroscopy with CLAS12 Focus on Generalized Parton Distributions Low Q Tagging Facility or Forward Tagger Electron scattering at “0” degrees (LowQ, post-target tagging): low Q2virtual photon  real photon Photons tagged by detecting the scattered electron Quasi-real photons are linearly polarized and the polarization can be determined event by event Highly segmented calorimiter BGO Opportunity to test / develop at SCAPA? • Hadron spectroscopy • Heavy mass baryon resonances (Cascades and -) • Meson spectroscopy • H target and search for exotics • 4He and other gas targets

  15. = = + + Exotic! GlueX: Confinement and the search for QCD exotics Confinement: Quarks cannot exist alone Simplest quark-structure is a meson Excite the glue: Study hybrid mesons (, K) JPC = 1-- , 1++ Hybrid Meson or , , , … ? G. Bali (, ) JPC = 0-+, 1-+, 2-+ 0+-, 1+-, 2+- Use a real photon beam

  16. GlueX: Confinement and the search for QCD exotics Glasgow: Diamond selection Coherent bremsstrahlung PolarimetrySCAPA ?

  17. Wider context EIC ? USA Germany Long standing Glasgow collaborations Sweden MAX IV Sweden Romania SCAPA Scotland 2020 2012 2016

  18. SCAPA Scottish Centre for the Application of Plasma-based Accelerators “Harnessing plasma waves as radiation and particle sources”Dino Jaroszynski Laser Wakefield Acceleration Ultra-short, ultra-intense laser pulses from commercially available table-top terawatt femtosecond lasers. Electron bunches: Mean energy above 1 GeV, an energy spread of about 1% and a peak current exceeding 1 kA. Protons: Yes please

  19. optical self-injection 6.5 MeV photo-injector SCAPA ALPHA-X running now ~20fs wakefield accelerator undulator Diamond 0.1 – 1 GeV g=200 - 2000 EDUCATION EDUCATIONEDUCATION Undergraduates PhD students Young postdocs. Opportunities for nuclear physicists Detector development RF PMTs, GEMs, Diamond detectors Diamonds Quality assessment, channelingradiation, polarimetry Fundamentsl Hadron and Nuclear Physics Lifetime measurements The unknown, open doors to ESS, ELI Compact Muon Source (next slide) SCAPA needsthe expertise ofnuclear physicists …. today! Beam characterization We already do this: Nature Physics 7, 867–871 (2011) D.Hamilton ++ Polarimetry Spectrometers and beam conditioning Detectors Data Acquisition / analysis SImluation Providing expertise opens many doors RF PMTs (J.Annand, Glasgow + Yerevan) ps timing resolution 500MHz rate capability plasma filled capillary laser 1 J 40 fs 800 nm Many of these make this

  20. Compact Muon Source at SCAPA Assay of radioactive waste: Glasgow applied project with NNL There exists, somewhere, alarge stockpile of barrels of unclassified radioactive waste. Need to determine the existence of high Z materials. Scattering of Muons. 500L Muonsfrom cosmic rays. Method is very promising. Rate of cosmic muons ~5Hz / m2 Assay will take 10s of years not feasible. Need a muon beam

  21. Compact Muon Source at SCAPA Similar to method used at ISIS Wakefield accelerator Light solid target Brem radiator Magnetic element 1 GeV 10Hz γn ➝ pπ- p- ➝m- nm- (l = 7.8m) Rate Estimate Compact muons: ~9kHz / m2 Compared to Cosmic muons~5Hz / m2 Simulated using Geant 4 and MAID2007, D. Hamilton, Glasgow Compact, made from “standard components”. >103rate increase over cosmics. Pion beam to do hadron physics (eg pion lifetime measurement with RF PMTs) Muon beam for materials science.

  22. Summary Missing Resonances Lots of progress internationally. Strangeness very important – 1st complete measurement Next few years should see definitive results. Jlab 12 CLAS12 and GlueX Continuing spectroscopy Heavier baryons Hybrid mesons SCAPA Many new opportunities Physics Detector development Education Compact muon source

  23. K production on n. Deuterium target How good a “free” neutron target is Deuterium ? G13. Compare photon asymmetry of p (n)nwithp  (free and bound p) p (n)nRussell Johnstone, Glasgow × Free ● Quasi free PRELIMINARY photon asymmetry    Coscm (-1.0 - +1.0) Each plot is 200MeV photon energy bin 1100-2150MeV Free and quasi-free proton Quasi free neutron good approx. to free, here.

  24. K production on n. Deuterium target G13 n (p)spn (p)sp Neil Hassall, Glasgow

  25. 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

  26. 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

  27. g8b preliminary results -  • 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

  28. g8b preliminary results -  • Results compared with previous results from GRAAL • 7, 50MeV Energy bins • 1175 -> 1475MeV • Good agreement with previous results PRELIMINARY

  29. g8b preliminary results -  • 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

  30. 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

  31. Resonances … and then the universe Pythagoras (c. 500 B.C.) Notes on a string which sound harmonious have simple ratios. Music of the Spheres If there is insufficient data even the wackiest of models cannot be ruled out. 1st Resonance model Created a system for tuning instruments The 1st musical scale

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