1 / 42

Kaon Photoproduction Results from CLAS

Kaon Photoproduction Results from CLAS. D. G. Ireland. “Missing” Baryon Resonances. Resonance Hunting…. Total Cross-sections + differential cross-sections + Partial Wave Analysis +. D(1232) P 33 N(1440)P 11 N(1520)D 13 N(1535)S 11 D (1600)P 33. Cross section.

chandler-mullen
Download Presentation

Kaon Photoproduction Results from CLAS

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. Kaon Photoproduction Results from CLAS D. G. Ireland EuNPC, Bochum

  2. “Missing” Baryon Resonances

  3. Resonance Hunting… Total Cross-sections + differential cross-sections + Partial Wave Analysis + ... D(1232)P33 N(1440)P11 N(1520)D13 N(1535)S11 D(1600)P33 Cross section 0.5 1.0 1.5 Eg (GeV) • Mostly done with pN scattering or photoproduction • Missing resonances may decay through other channels

  4. Meson Photoproduction Cross Sections

  5. Evidence for new resonance? With D13 Without D13 Mart & Benhold, Phys. Rev. C 61 012201(R) (1999)

  6. Transversity Amplitudes } b1 = 1/2[(S1 + S2) + i(N - D)] } b2 = 1/2[(S1 + S2) - i(N - D)] } b3 = 1/2[(S1 - S2) - i(N + D)] } b4 = 1/2[(S1 - S2) + i(N + D)] N, S1,S2, D: Helicity Amplitudes

  7. Experimental Observables

  8. gp →KL Reaction Kinematics K+ proton proton Hyperon is self-analysing Cross Section without target polarisation

  9. CEBAF at Jefferson Laboratory

  10. CLAS

  11. Tagged Photons at CLAS • Eg = E0 – E’ • Circular Polarisation: polarised electron beam, amorphous radiator • Linear polarisation: Crystal (diamond) radiator

  12. gp →KL Cross Section Measurements R. Bradford et al., Phys. Rev. C 73, 035202 (2006).

  13. Recoil Polarisation K+ proton proton Hyperon is self-analysing

  14. Recoil Polarisation (P) gp→KL Kaon-MAID GENT Guidal, Laget, Vanderhaeghen J. McNabb et al. (CLAS) Phys. Rev. C 69, 042201 (2004).

  15. Beam-Recoil Double Polarisation (Cx’,Cz’) K+ proton proton Hyperon is self-analysing

  16. L Polarisation → L fully polarised R. Bradford et al., Phys. Rev. C 75, 035205 (2007).

  17. Photon Beam Asymmetry (S) K+ proton proton

  18. Linear Polarisation analysis Photon Linear Polarisation Particle ID LS0 Thesis work of Craig Paterson (Glasgow)

  19. gp →KL Photon Beam Asymmetry

  20. gp →KL Photon Beam Asymmetry PRELIMINARY

  21. gp →KL Photon Beam Asymmetry PRELIMINARY

  22. Beam-Recoil Double Polarisation (Ox,Oz) K+ proton proton

  23. gp →KL: Extracting Ox and Oz

  24. gp →KL Beam-Recoil Ox and Oz Ox PRELIMINARY Oz PRELIMINARY

  25. Experimental Observables

  26. Data taking completed Currently being analysed Data on quasifree neutron and proton Circular and Linear Polarisation Outlook – Deuterium Target

  27. Outlook – FROzen Spin Target (FROST) Target can be longitudinally or transversely polarised • “Complete” measurement possible • First part of run complete • Undergoing calibration • Second period to run soon…

  28. Conclusions • Kaon Photoproduction results from CLAS: • Published results: s, P, Cx, Cz • Preliminary results: S, T, Ox, Oz • In the near future: • Same set of results for 2H target (quasifree neutron and proton) • “Complete” results (FROST) • Next few years: • Complete set on 2H and p (HDIce)

  29. Backup Slides…

  30. Resonances in Quark Models

  31. Kaon Photoproduction

  32. Contributing Processes + channel coupling…

  33. Helicity Amplitudes } NNo overall helicity flip = |g – (p -L)| } S1Single helicity flip } S2Single helicity flip } DDouble helicity flip

  34. Cross Section Measurements R. Bradford et al., Phys. Rev. C 73, 035202 (2006).

  35. Cross Section Measurements R. Bradford et al., Phys. Rev. C 73, 035202 (2006).

  36. Cross Section Measurements R. Bradford et al., Phys. Rev. C 73, 035202 (2006).

  37. Beam-Recoil Double Polarisation Cz Saclay, Argonne, Pittsburgh GENT Regge+Resonance Kaon-MAID Bonn, Giessen, Gatchina Shklyar Lenske Mosel R. Bradford et al., Phys. Rev. C 75, 035205 (2007).

  38. Beam-Recoil Double Polarisation Cx Saclay, Argonne, Pittsburgh Bonn, Giessen, Gatchina Shklyar Lenske Mosel Regge+Resonance GENT Kaon-MAID R. Bradford et al., Phys. Rev. C 75, 035205 (2007).

  39. Photon Beam Asymmetry

  40. Photon Beam Asymmetry PRELIMINARY

  41. Photon Beam Asymmetry PRELIMINARY

  42. Recoil - Comparison PRELIMINARY g8b ~Factor of 4 increase in statistics from best previous measurements Prev CLAS GRAAL

More Related