1 / 39

1.- Introduction 2.- MAMI Accelerator 3.- A2 Real Photon Facility 4.- nGDH DAPHNE

Institut für Kernphysik. Recent result from the A2 Real Photon Facility at MAMI. 1.- Introduction 2.- MAMI Accelerator 3.- A2 Real Photon Facility 4.- nGDH DAPHNE 5.- Crystal Ball/TAPS/MainzPT 6.- Conclusions and Outlook. NSTAR 2009

falboj
Download Presentation

1.- Introduction 2.- MAMI Accelerator 3.- A2 Real Photon Facility 4.- nGDH DAPHNE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Institut für Kernphysik Recent result from the A2 Real Photon Facility at MAMI 1.- Introduction 2.- MAMI Accelerator 3.- A2 Real Photon Facility 4.- nGDH DAPHNE 5.- Crystal Ball/TAPS/MainzPT 6.- Conclusions and Outlook NSTAR 2009 WORKSHOP ON THE PHYSICS OF EXCITED NUCLEONS19 - 22 April 2009Beijing, China Andreas Thomas A2- and CBall@MAMI- Collaborations

  2. 1557MeV (since 2008) MAMI C • Parameter (since 2006) • 1507MeV, sE=0.100MeV • max. 100mA • eh=9 nm rad, ev=0.5 nm rad • as MAMI B ! MAMI B • Beam Parameter (beam since 1990) • 885MeV, sE=0.068MeV • max. 103mA cw • eh=8 nm rad, ev=0.5 nm rad • (Beam Focus ~mm) • Halo: < 10-5 bei r > 5∙sr • ca. 6000h – 7000h operation / year

  3. A2 Tagging system (Glasgow,Mainz) 1. Production und energy measurement of the Bremsstrahlungs photons Determination of the degree of polarization of the electron beam (Moeller Polarimeter); Circularly pol. photons 2. 3. Coherent production of linearly polarized photons on a diamond radiator Primary "Vacoflux" Foil Moeller trigger Coincidence beam = ± 8 . 1 0 . 2 % p t E e - E e - e - Electron beam Radiator (Moeller target)

  4. Polarised Photons @ MAMI C Eg = 75 ... 1475 MeV DEg = 4 MeV Ng ~ 105 s-1 MeV-1

  5. Data from the GDH experiment @ MAMI B with DAPHNE detector

  6. Detector: Produced by groups from Saclay,Pavia

  7. Proton

  8. Measurements in 1998 at MAMI with DAPHNE and Bonn PT Partial reaction channels Input for PWA to extract resonance parameters

  9. Bonn Polarized target Neutron [C.Bradtke et al., NIM A436, 430 (1999)] „Frozen Spin Mode“ • Polarization : DNP at high B-Field (2.5 T) • Measurement : very low T ´freeze´ up the spin (0.4 Tesla) relaxation time T 200 h » New Technology: horizontal cryostat with integrated solenoid (holding field) 1.2 Kelvin 0.42 Tesla equiv. 780mm Cu (100mm NbTi)

  10. Butanol (C4H9OH) (C4D9OD) [Hartmut Dutz, PT Universität Bonn]

  11. Target material [St. Goertz, PT Ruhr-Universität Bochum] • Density and species of the radicals • are very important for: • maximum degree of polarization • polarization build up times • relaxation times • Trityl-Radikal D-Butanol [Gerhard Reicherz, PT Ruhr-Universität Bochum] Highest Deuteron polarisation due to new doping material with small ESR from Bochum. [W.Meyer et al.]

  12. g d Reaction channels on deuterium in the MAMI B energy range (< 855MeV): Neutron Desintegration Coherent pion p. Incoherent pion p. Double pion p. Coherent eta p. Incoherent eta p.

  13. Helicity structure of the deuterons excitation spectrum Gerasimov-Drell-Hearn sum rule (GDH) for nuclei • Static properties • of the nuclei: • mass • charge • anomalous magnetic moment • Derived 1965 using general asumption: • Lorentz and gauge invariance ->Low energy theorem • causality ->dispersion relation • unitarity ->opt. theorem [S.B.Gerasimov: Sov.J.Nucl.Phys.2(1966)430] [S.D.Drell, A.C.Hearn: Phys.Rev.Lett.16(1966)908]

  14. Nucleon Nucleon Interaction • Meson Exchange currents • Final State Interaction • Relativistic Effects, Retardation Model: [H. Arenhövel, et al., Phys. Rev. Lett. 93 (2004) 202301]

  15. Helicity dependent deuteron photodesintegration [Arenhövel et al. , Physics Letters B 407 (1997) 1-7] „Flip of a single quark“: sp >> sa u u d photon (Spin 1) photon (Spin 1) D(1232)-resonance (Spin3/2) proton (neutron) (Spin 1/2) The D resonance can better be excited if the inital spins are parallel at 300MeV sa >> sp P N P N 1S0 resonant state at 68KeV (Spin 0) 3S1 deuteron ground state (Spin 1) The resonant 1S0 state can only be reached if the inital spins are antiparallel at energies close to break-up threshold (2-3MeV) IGDH= 0.65mb

  16. Phys. Letters B 672(2009)328-332

  17. Model AFS New precission data set to determine the deuteron-GDH-sumrule above p-threshold [Phys. Letters B 672(2009)328-332

  18. Partial reaction channels and polarisation observables deliver more information to improve the deuteron models and our knowledge on the neutron. (Better Models are needed.)

  19. 1 S s a Deuterated Butanol was used as target material in 98 (pilot exp.) and 2003 s p Photon Nucleon P(Neutron) ~ 0.92 P(Deuteron) Deuteron Partial reaction channels on quasifree neutron P N 3Helium GDH-Integral with small systematic error New Exp. In May 2009 on 3Helium P P N Gerasimov-Drell-Hearn sum rule (GDH) for nuclei

  20. [W.Heil, J.Krimmer, P.Bartolomez]

  21. 4p photon Spectrometer @ MAMI TAPS: 364 BaF2 detectors Max. kin. energy: p+- : 180 MeV K+- : 280 MeV P : 360 MeV Crystal Ball: 672 NaJ detectors Max. kin. energy: m+- : 233MeV p+- : 240 MeV K+- : 341 MeV P : 425 MeV Vertex detector: 2 Cylindr. MWPCs 480 wires, 320stripes PID detector: 24 thin plastic detectors

  22. Crystal Ball / TAPS

  23. Polarized Target for Crystal Ball Tagged CW photon beam 4p- detector Frozen spin target (20mKelvin, 5Tesla) Pproton ~ 95% Pdeuteron~70% All directions of polarization Transverse And Longitudinal Internal Holding coil New 3He4He-Dilution refrigerator (in collaboration with JINR Dubna)

  24. High Field 1T Threshold Production Transverse Field

  25. Photoproduction with polarized beam and polarized target lin lin circ g Beam P P P g g g unpol æ p ö æ p p ö + - ç ÷ ç ÷ Target 0 , , è 2 ø è 4 4 ø Beam Target æ ö s d S ç ÷ P - - unpol W è d ø P - - H F + Recoil observables [D.Watts, M.Sikora] Wed.,Session6 x P T P - - y P - - G E z

  26. Conclusion and Outlook Future: In A2 we continue to do double polarised experiments with polarised beam, polarised targets (3Helium 5/2009 H,D-Butanol 12/2009) and recoil-polarimeter. Proton (Frozen Spin) Threshold, Transverse, Complete exp. Neutron (D,3He) Theoretical description MAMI C is delivering polarised beam with now 1557 MeV and high Intensity for the experiments since 2008 New precission data set from the neutron-GDH-experiment with ‚DAPHNE‘ detector and is published [Phys. Letters B 672(2009)328-332] Paper on Helicity Dependent Deuteron Photodisintegration between 160 and 480 MeV and single pion production up to 800 MeV is under preparation. Data from ‚Crystal Ball‘ detector in combination with TAPS and further detectors at MAMI B (882MeV) and MAMI C (1557MeV) are under analysis. Publications 2009: Dalitz Plot Parameter a , p0η-production, Measurement h-mass, rare h-decays, MDM, Helicty asymmetries pp

  27. Helicity Dependent Deuteron Photodisintegration between 160 and 480 MeV to be submitted EPJA

  28. Crystal Ball @ MAMI Collaboration Run 2004/2005  700 Stunden Tests 3600 Stunden Datennahme 12 PhD

  29. The GDH collaboration J.Ahrens9,S.Altieri15,16,J.R.M.Annand6,G.Anton3,H.-J.Arends9,K.Aulenbacher9,R.Beck9,C.Bradtke1,A.Braghieri15,N.Degrande4,N.d'Hose5,H.Dutz2, S.Goertz1,P.Grabmayr17,K.Hansen8,J.Harmsen1, S.Hasegawa13,T.Hasegawa11,E.Heid9, K.Helbing3,H.Holvoet4, L.VanHoorebeke4,N.Horikawa14,T.Iwata13,P.Jennewein9, T.Kageya14,B.Kiel2,F.Klein2,R.Kondratiev12,K.Kossert7,J.Krimmer17,M.Lang9,B.Lannoy4,R.Leukel9,V.Lisin12,T.Matsuda11,J.C.McGeorge6,A.Meier1,D.Menze2,W.Meyer1,T.Michel3,J.Naumann3,A.Panzeri15,16,P.Pedroni15,T.Pinelli15,16,I.Preobrajenski9,12,E.Radtke1,E.Reichert10,G.Reicherz1,Ch.Rohlof2, G.Rosner6, D.Ryckbosch4,F.Sadiq6,M.Sauer17,B.Schoch2, M.Schumacher7,B.Seitz7, T.Speckner3,M.Steigerwald9,N.Takabayashi13,G.Tamas9, A.Thomas9, R.van de Vyver4, A.Wakai14,W.Weihofen7,F.Wissmann7,F.Zapadtka7,G.Zeitler3 1Institute of Experimental Physics, Ruhr-University,Bochum, Germany 2Physics Institute, University of Bonn, Germany3Physics Institute, University of Erlangen-Nuernberg,Erlangen, Germany 4Nuclear Physics Laboratory, Gent, Belgium 5CEA Saclay, DSM/DAPNIA/SPhN, Gif-sur-Yvette, France 6Department of Physics & Astronomy, University of Glasgow, U.K.7II.Physics Institute, University of Goettingen, Germany8Department of Physics, University of Lund, Sweden9,10Institute of Nucl. Physics and Inst. of Physics, University of Mainz, Germany 11Faculty of Engineering, Miyazaki University, Miyazaki, Japan 12INR, Academy of Science, Moscow, Russia 13,14 Department of Physics and CIRSE, Nagoya University, Nagoya, Japan 15,16 INFN Sezione di Pavia and Dept. of Nucl. Physics of the University , Pavia, Italy 17 Physics Institute, University of Tuebingen, Germany

  30. Rot TAPS Daten Kurven:ChPT Data set with high statistics for p and pp production [F.Zehr, S.Schumann] gp  pp0p0

  31. Excitation Spectrum of the nucleon Pion Production Eta Production polarisation observables essential

  32. lin lin circ g Beam P P P g g g unpol æ p ö æ p p ö + - ç ÷ ç ÷ Target 0 , , è 2 ø è 4 4 ø æ ö s d S ç ÷ P - - unpol W è d ø P - - H F x P T P - - y P - - G E z Photoproduction of pseudoscalar p, h, h‘, K with polarised beam and target Strahl Target

  33. N N Pion Photoproduction with Polarized Beam and Polarized Target EL, ML Multipole components of the electromagnetic radiation Angular momentum and parity conservation Multipole amplitudes: Angular momentum Parity EL : ML :

  34. p-prod. -> D(1232) ->E2/M1 ->Deformation [Phys. Rev. Lett. 84, 5950 (2000)] Connection between and and Multipoles and Resonances gp np+ Ds[mb] MAID2000 gp pp0 N N Eg[MeV] s s Eg[MeV]

  35. 2nd Resonance region -> D13(1520) ->Resonance Parameters 20% changed Connection between and and Multipoles and Resonances [Phys. Rev. Lett. 88 (2002) 232002] N N s s

More Related