Exotic Baryons and Spin Physics in Japan. Introduction. SPring-8. J-PARC Summary. K.Imai (Kyoto & Riken) Penta-quark Θ + Λ(1405)

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1 Exotic Baryons and Spin Physics in Japan K.Imai: K.Imai: Spin Spin /8/6 03/8/6 (Seattle) (Seattle) Introduction K.Imai (Kyoto & Riken) SPring-8 Penta-quark Θ + Λ(1405) J-PARC Summary

2 Brief History of Spin in/from Japan Polarized (proton) target pp, γn, πn, KN Masaike, Horikawa,, Polarized (proton) beam RCNP, KEK-PS Mori, Hatanaka, K.I,, International collaboration FNAL-E704, SMC-Compass, Hermes, RHIC-Spin SPring-8 J-PARC

3 SPring-8 (Super Photon Ring-8 GeV) Third-generation synchrotron radiation facility Circumference: 1436 m 8 GeV 100 ma BL33LEP

4 Laser Electron Photon at Spring-8 (LEPS) g

Energy Spectrum 0.7 0.6 0.5 0.4 0.3 2.4 GeV 8 GeV 0.2 0.

5 Energy Spectrum GeV 8 GeV Eγ (GeV) Intensity (Typ.) : 2.5 * 10 6 cps

6 Polarization of LEPS Beam Linear Polarization : 95 % at 2.4 GeV

7 Tagging system Compton Scattering Tagging counter (SSD + Plastic Scint.) BM1 BM2 CR2 LEP Laser Tagging Region : 1.5 GeV< E γ < 2.4 GeV

8 Physics Subjects φ production glue-ball exchange s-content (pol. HD Target) Baryon spectroscopy Spin observables (Linear pol. γ) GDH Λ(1405) Mass shifts of vector mesons

9 Discovery of - Θ + M = MeV G < 25 MeV Gaussian significance 4.6s g +n -> Q + +K -, Q + -> K + n T. Nakano et al., Phys.Rev.Lett. 91 (2003) hep-ex/ background

10 Θ + (Z + ) prediction of anti-decuplet Q + (1530) D. Diakonov, V. Petrov, and M. Polyakov, Z. Phys. A 359 (1997) 305. Exotic: S=+1 Low mass: 1530 MeV Narrow width: < 15 Me J p =1/2 + M = [ *Y] MeV

11 The LEPS collaboration Research Center for Nuclear Physics, Osaka University T. Nakano, D.S. Ahn, M. Fujiwara, T. Hotta, K. Kino, H. Kohri, T. Matsumura, T. Mibe, A. Shimizu, M. Sumihama Pusan National University J.K. Ahn Konan University H. Akimune Japan Atomic Energy Research Institute / SPring-8 Y. Asano, N. Muramatsu Institute of Physics, Academia Sinica, Taiwan W.C. Chang, T.H. Chang, D.S. Oshuev, C.W. Wang, S.C. Wang Japan Synchrotron Radiation Research Institute (JASRI) / SPring-8 S. Date, H. Ejiri, N. Kumagai, Y. Ohashi, H. Ookuma, H.Toyokawa, T. Yorita Ohio University K. Hicks Kyoto University K. Imai, M. Miyabe, M. Niiyama, T. Sasaki, M. Yosoi Chiba University H. Kawai, T. Ooba, Y. Shiino Yamagata University T. Iwata Wakayama Medical University S. Makino Nagoya University T. Fukui Osaka University H. Nakamura, M. Nomachi, A. Sakaguchi, Y. Sugaya, University of Saskatchewan C. Rangacharyulu Institute for High Energy Physics (IHEP), Moscow P. Shagin Laboratory of Nuclear Science, Tohoku University H. Shimizu, T. Ishikawa University of Michigan K. Yonehara Michigan State University R.G.T. Zegers Seoul National University H. Fujimura Miyazaki University T. Matsuda, Y. Toi

12 LEPS detector Aerogel Cerenkov (n=1.03) Start counter Dipole Magnet (0.7 T) TOF wall iquid Hydrogen arget (50mm thick) g Silicon Vertex Detector MWDC 1 MWDC 2 MWDC 3 1m

13 Target Region 30 Hz for 800 Charge veto Target (LH 2 ) AC(n=1.03) Start counter (SC)

14 Identification of Q + g n K - Q + K - K + n K - missing mass gives Q + mass K + K - missing mass gives n Problems: no neutron target CH start counter (n is part of C!) background ffik + K - (produced from n & p) Non-resonant KK L(1520) Q +?

15 Fermi motion correction est-case: n K + Σ - K + π - n p K + Λ K + π - p Correction works better when Q- value is small. K + p - missing mass Start counter (CH) K + missing mass K + missing mass L S - K + missing mass (corrected) L LH 2 target K + missing mass (corrected) Correction: MM gk+ (corrected) = MM gk+ - MM gk+p- + M n

16 Q + identification M = MeV G < 25 MeV Gaussian significance 4.6s g n -> K- K+ n Background is from non-resonant K + K - production off the neutron/nucleus is nearly identical to non-resonant K + K - production off the proton shape can be determined from events from LH 2 counter using the same cuts except for: Proton-recoil cut is removed L(1520) events are removed (only from p) background

17 Confirmation from US and Russia DIANA/ITEP K + Xe K 0 p X (K + n K 0 p) CLAS/JLAB g d p K + K - n M = MeV G < 9 MeV hep-ex/ M = MeV G < 21 MeV hep-ex/

18 Further confirmation from SAPHIR (ELSA) hep-ex γ p->θ g + K 0 p M=1540 MeV Γ<25 MeV

19 E522 (KEK-PS) Search for H-dibaryon resonance via 12 C(K -,K + ΛΛ) and study of ΞN interactions data taking by-product? Q + search by p(p-,k-) Q + at p(p-)=1.9 GeV/c (under analysis) No peak was observed in old BC data (poor statistics)

20 Questions about Q + Spin-parity: J π = ½ + or ½ - or 3/2 s-wave or p-wave? K+n -> K+n phase shift analysis (pol. d target) pol.γ N -> K- Θ+ decay distribution of Θ+ π p -> K- Θ+ decay distribution of Θ+ width: How narrow? only upper limit ( 9 MeV, ~20 MeV) invariant spectroscopy: K O +p -> invariant mass few MeV? K+p -> π+ Θ+ KEK-SKS spectrometer ( E~1.5 MeV) for comparison Λ(1520) Γ=16MeV Br~45% for KN Structure(size): 5quark or KN molecule? A-dependence of photo-production of Θ+

21 To establish exotics (anti-decuplet) Ξ - - n K - -> K + Ξ - - p K - -> K + π + Ξ - - Ξ + p K - -> K 0 π- Ξ + If M(Ξ -- ) ~ 1750 MeV (Jaffe & Wilczek, hep-ph/ ) >2GeV/c K- beam (BNL or KEK or J-PARC)!

22 Λ(1405) 3-quark or KN bound state old question but current topics (K-nuclei) Low statistics data from bubble ch. Photo-production from H and A-target Λ(1405) -> Σπ, Σ -> πn measurement of Σ with ~cm flight length -> Time Projection Chamber (TPC)

23 p(g,k + (p +- )) at SP8 by J.K.Ahn

27 Experimental Setup with TPC Dipole Spectrometer Solenoid g (Niiyama et al.)

28 TPC Readout Chamber p S p p K+ ~1000 pads and ~100 wires for readout s xy ~350mm and s z ~ 500mm DM/M ~ 0.5% for L(1405) mass

J-PARC Facility Materials and Life Science Experimental Facility Nuclear and Particle Experimental Facility Nuclear Transmutation Linac

31 J-PARC Facility Materials and Life Science Experimental Facility Nuclear and Particle Experimental Facility Nuclear Transmutation Linac (350m) 3 GeV Synchrotron (25 Hz, 1MW) Neutrino to Kamiokande 50 GeV Synchrotron (0.75 MW) J-PARC = Japan Proton Accelerator Research Complex

32 Present Status

33 D-magnets and RF cavity (50GeV) Mass production of Bending magnets RF Cavity

34 LOI for 50 GeV PS 30 LOI s were submitted to J-PARC (02/12) LOI related to spin physics Baryon spectroscopy, spin asymmetry in pp scattering, muon g-2, muon EDM, T-violation in K-decay NPFC Committee has made recommendations to the Project Leader (S. Nagamiya) Most likely K, π separated beam of 2.0 GeV/c and ν beam to start! J-PARC will be a unique facility for hadron physics. Proposals and suggestions are always welcome!

35 Summary Penta-quark (Q + ) discovered at SPring-8 was now firmly established. M~1540, Γ<20MeV Further studies of Q + and Λ(1405) will be made with new SP-8 4π spectrometer (TPC) (and hopefully at KEK-PS ) To establish anti-decuplet, Ξ--, Ξ+ should be searched (at KEK-PS, BNL-AGS or J-PARC) J-PARC will play a key role for QCD physics, (such as exotic hadron spectroscopy).

Evidence for Narrow S=+1 Baryon Resonance at LEPS/SPring-8 T. Nakano (RCNP, Osaka Univ)

Evidence for Narrow S=+1 Baryon Resonance at LEPS/SPring-8 T. Nakano (RCNP, Osaka Univ) Introduction Experiment Evidence for Q + Results from other labs Conclusion & Outlook KEK Seminar August 5, 2003