(RCNP, Osaka University) for the LEPS collaboration
Highlights and Prospects from LEPS and LEPS2 LEPS Takashi NAKANO (RCNP, Osaka University) for the LEPS collaboration Osaka, December 9th, 2010 LEPS Collaboration Research Center for Nuclear Physics, Osaka University D.S. Ahn, M. Fujiwara,T. Hotta, Y. Kato, H. Kohri, Y. Maeda, T. Mibe, N. Muramatsu, T. Nakano, S.Y. Ryu, T. Sawada,M. Yosoi, T. Yorita Department of Physics, Pusan National University J.K. Ahn School of Physics, Seoul National University H.C. Bhang Department of Physics, Konan University H. Akimune Japan Atomic Energy Research Institute / SPring-8 Y. Asano Institute of Physics, Academia Sinica W.C. Chang, J.Y. Chen Japan Synchrotron Radiation Research Institute (JASRI) / SPring-8 S. Date', H. Ejiri, N. Kumagai, Y. Ohashi, H. Ohkuma, H. Toyokawa Department of Physics and Astronomy, Ohio University K. Hicks Department of Physics, Kyoto University M. Niiyama, K. Imai, H. Fujimura, M. Miyabe, T. Tsunemi Department of Physics, Chiba University H. Kawai, T. Ooba, Y. Shiino Wakayama Medical University S. Makino Department of Physics and Astrophysics, Nagoya University S. Fukui Department of Physics, Yamagata University T. Iwata Department of Physics, Osaka University S. Ajimura, K. Horie, M. Nomachi, A. Sakaguchi, S. Shimizu, Y. Sugaya Department of Physics and Engineering Physics, University of Saskatchewan C. Rangacharyulu Laboratory of Nuclear Science, Tohoku University T. Ishikawa, H. Shimizu Department of Applied Physics, Miyazaki University T. Matsuda, Y. Toi Institute for Protein Research, Osaka University M. Yoshimura National Defense Academy in Japan T. Matsumura RIKEN Y. Nakatsugawa Department of Education, Gifu University M. Sumihama, Laser Electron Photon beamline at SPring-8 Backward-Compton Scattered Photon
8 GeV electrons in SPring nm Ar laser (3.5eV maximum 2.4 GeV photon Laser Power ~6 W Photon Flux~1 Mcps E measured by tagging a recoil electron E>1.5 GeV, E ~10 MeV Laser linear polarization % Highly polarized beam Linear Polarization of beam PWO measurement tagged photon energy [GeV] photon energy [MeV] Setup of LEPS Detectors
Only FWD spectrometer 20x 10 1.5 Setup of LEPS Detectors
1.5 g E // B Polarized HD target will be ready soon. Talk by YOSOI (P4) PID in LEPS Spectrometer
TOF Dipole Magnet 0.7 Tesla Target Start Counter DC2 DC3 DC1 SVTX AC(n=1.03) Photons K/p separation K+ p+ Momentum [GeV/c] Mass/Charge [GeV/c2] P ~6 MeV/c for 1 GeV/c TOF ~150 ps MASS ~30 MeV/c2 for 1 GeV/c Kaon Features of LEPS facility
High linear polarization Flat energy spectrum Good forward acceptance Good p/K separation Linear polarization can be used to studyspin-parity of exchanged particle in t-channel. Forward spectrometer is suitable for studying reactions near production threshold. Tagged photon energy region is close to ss thresholds. f(1020) Diffractive Photoproduction of vector meson
Vector Meson Dominance Meson Exchange Pomeron Exchange q _ _ qq = r, w, f ... g N r, w Dominant at low energies g r, w f (~ss) Slowly increasing with energy N uud Scattering amplitude Pomeron 2nd Pomeron Total crosssection f photoproduction near production threshold
Titov, Lee, Toki Phys.Rev C59(1999) 2993 Data from: SLAC('73), Bonn(74),DESY(78) P2 : 2nd pomeron~ 0+ glueball(Nakano, Toki (1998)) Decay asymmetry helps to disentangle relative contributions Polarization observables with linearly polarized photon
f meson rest frame K+ eg Decay Plane // g natural parity exchange (-1)J (Pomeron, Scalar Glueball, Scalar mesons) Polarization vector of g K- eg Decay Planeg unnatural parity exchange -(-1)J (Pseudoscalar mesons p,h) K+ Decay angulardistribution of f meson Relative contributions from natural, unnatural parity exchanges Differential cross section at t=-|t|min
Phys. Rev. Lett. 95, (2005) Bump is confirmed by CLAS. Talk by DEY(EM1) Decay angular distribution
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