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Photoproduction and Decays of Pseudoscalar Mesons in CLAS

Photoproduction and Decays of Pseudoscalar Mesons in CLAS. Moskov Amaryan Old Dominion University Norfolk, Virginia, USA . Outline. CLAS setup at JLAB. -Classification of Mesons. - Hadronic decays.

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Photoproduction and Decays of Pseudoscalar Mesons in CLAS

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  1. Photoproduction and Decays of Pseudoscalar Mesons in CLAS MoskovAmaryan Old Dominion University Norfolk, Virginia, USA M.Amaryan, University of Bochum, December 6, 2011

  2. Outline • CLAS setup at JLAB -Classification of Mesons -Hadronic decays -Radiative decays -Dalitz decays -Summary M.Amaryan, University of Bochum, December 6, 2011

  3. CLAS JLab Site: The 6 GeV CW Electron Accelerator Emax ~ 6 GeV Imax ~ 200 mA Duty Factor ~ 100% sE/E ~ 2.5 10-5 Beam P ~ 80% Eg(tagged) ~ 0.8- 5.5 GeV M.Amaryan, University of Bochum, December 6, 2011

  4. The CLAS Photon Tagger M.Amaryan, University of Bochum, December 6, 2011

  5. CEBAFLarge Acceptance Spectrometer Torus magnet 6 superconducting coils Large angle calorimeters Lead/scintillator, 512 PMTs Liquid D2 (H2)target + g start counter; e minitorus Gas Cherenkov counters e/p separation, 216 PMTs Drift chambers argon/CO2 gas, 35,000 cells Electromagnetic calorimeters Lead/scintillator, 1296 PMTs Time-of-flight counters plastic scintillators, 684 PMTs M.Amaryan, University of Bochum, December 6, 2011

  6. Horizontal cut through the CLAS detector M.Amaryan, University of Bochum, December 6, 2011

  7. (Reminder) M.Amaryan, University of Bochum, December 6, 2011

  8. Meson Families J=L+S P=(-1)L+1 C=(-1)L+S G=(-1)L+S+I M.Amaryan, University of Bochum, December 6, 2011

  9. In the SU(3) Group Theory Language M.Amaryan, University of Bochum, December 6, 2011

  10. OUTLINE - Photoproduction of Pseudoscalar Mesons with CLAS Hadronic Decays Radiative Decays Also Vector Mesons: M.Amaryan, University of Bochum, December 6, 2011

  11. Missing Mass Distribution gp pX Single charged track events identified as a proton M.Amaryan, University of Bochum, December 6, 2011

  12. Missing Mass π0 η 3 charged track events identified as a proton, π+ and π- M.Amaryan, University of Bochum, December 6, 2011

  13. Okubo-Zweig-Iizuka Rule OZI allowed OZI suppressed M.Amaryan, University of Bochum, December 6, 2011

  14. ω-ϕ Interference in e+e- annihilation M.N.Achasov hep-ex/0604051 It depends on production and decay amplitudes of interfering resonances as well as on their relative phases. How would it look like in photoproduction? M.Amaryan, University of Bochum, December 6, 2011

  15. OZI Rule Violating Decay of ϕ meson in photoproduction γ+p = pπ+π-π0 ω ϕ η‘ Hadronic decay η‘ ϕ η (~2M events) M.Amaryan, University of Bochum, December 6, 2011

  16. G-Parity Violating Decay of φ Meson ? η‘ f1(1285) PDG Exp. limit Br<1.8x10-5 Φ M=1.021 GeV σ = 0.005 GeV Theory prediction: Br( ) ~3x10-7 Achasov, I.J.M.Phys. A, Vol.7, No. 20(1992, 4825) M.Amaryan, University of Bochum, December 6, 2011

  17. ~340K η’ events and ~1M on tape arXiv:1012.1117v2 [hep-ex] ~40K events M.Amaryan, University of Bochum, December 6, 2011

  18. M.Amaryan, University of Bochum, December 6, 2011

  19. not corrected for acceptance M.Amaryan, University of Bochum, December 6, 2011

  20. M.Amaryan, University of Bochum, December 6, 2011

  21. M.Amaryan, University of Bochum, December 6, 2011

  22. From g11 run only Adding g12 will reduce stat.err. by factor of two M.Amaryan, University of Bochum, December 6, 2011

  23. M.Amaryan, University of Bochum, December 6, 2011

  24. Radiative Decay ρ/ M.Amaryan, University of Bochum, December 6, 2011

  25. WASA-at-COSY[17] BNL-AGS[18] Theory: F.Stollenwerk et al., arXiv:1108.2419v1 [nucl-th] η’->π+π-γ η->π+π-γ CLAS  Not corrected Eγ [GeV] Eγ [GeV] M.Amaryan, University of Bochum, December 6, 2011

  26. CLAS Not corrected for acceptance M.Amaryan, University of Bochum, December 6, 2011

  27. Dalitz Decay of Pseudoscalar Mesons M.Amaryan, University of Bochum, December 6, 2011

  28. M.Amaryan, University of Bochum, December 6, 2011

  29. Summary • High statistics experimental resultson rare and dominant • decay modes of pseudoscalar and vector mesons are • obtained with CLAS at JLAB. • In some channels CLAS data are exceeding the world • statistics • Dalitz decay of etaprime is observed for the first time • -Combining data from different world facilities will help • to provide high quality and high statistics data • -We believe that common efforts of European and US • groups related to meson decays will be extremely useful • Thanks for the opportunity to give a seminar in University • of Bochum ! M.Amaryan, University of Bochum, December 6, 2011

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