Photoreactions with Polarized HD target at SPring-8 1. SPring-8 Facility 2. Physics Motivation 3. HD projects: Polarized proton and deuteron target: HD target project for complete polarization observables. M. 19 September 2009, Moscow

Collaborators of HD project K. Fukuda, M. Fujiwara, T. Hotta, H. Kohri, T. Kunimatsu, C. Morisaki, T. Ohta, K. Ueda, M. Uraki, M. Utsuro, M. Yosoi, (RCNP, Osaka) S. Bouchigny, J.P. Didelez, G. Rouille (IN2P3, Orsay, France) M. Tanaka (Kobe Tokiwa University, Japan) Su-Yin Wang (Institute of Physics, Academia Sinica, Taiwan)

Super Photon ring – 8 GeV 8 GeV electron beam Diameter ≈457 m RF 508 MHz One-bunch is spread within  ＝ 12 psec. Beam Current = 100 mA Life time 30 － 50 hours Osaka – SPring-8: about 100 km, One hour highway drive. Sapporo Tokyo Nagoya Osaka Russia China South Korea North Korea

Back Compton Scattering Back Compton scattering Incident electrons E e Incident Photons E l Scattered electrons Scattered photons E    : Electron velocity /c  L : Incident angle of laser photon  : Scattered angle of photon Energy of BCS photons Head-on collision (  L =0) ex. E e =8 GeV, (Laser =351 nm) 2.4 GeV Maximum

LEPS facility b) laser hutch a) SPring-8 SR ring c) experimental hutch Laser light 8 GeV electron Recoil electron Electron tagging Collision Inverse Compton  -ray M. Fujiwara, Nuclear Physics News 11 (2001)

Laser System 351 nm Ar laser （ multi-line UV, 4 W ） 10 6 photons/sec on target Linearly polarized laser beam Polarized LEP beam ~95% at 2.4 GeV tagged 351 nm 257 nm Energy spectrum tagged 351 nm 257 nm Linear Polarization

LEPS spectrometer  Liquid Hydrogen Target (15 cm thick ) Aerogel Cherenkov (n=1.03) Start counter Silicon Vertex Detector Dipole Magnet (0.7 T) MWDC 1 MWDC 2MWDC 3 1m1m TOF wall

Missing mass spectrum p( ,K + )  (1116) p( ,K + )  0 (1193) 1.5 ~ 2.4 GeV 0.6 < cos  cm < 1 Photon beam asymmetry

Photon beam asymmetry  N : K + photoproduction yield  : K + azimuthal angle P  : Polarization of photon n : Normalization factor for N v For all events R. Zegers et al., Phys. Rev. Lett. 91 (2003) M. Sumihama et al., C 73 (2006) H. Kohri et al., Phys. Rev. Lett. 97 (2006)

LEPS experiments (2000 – 2009)

Published Papers from ( Results from polarization observables in Red )  p -> K +   p ->  +  0 R. G. T. Zegers et al. Phys. Rev. Lett Pentaquark search T. Nakano et al. Phys. Rev. Lett  meson production Li, C, Al, Cu T. Ishikawa et al. Phys. Lett. B  meson production proton target T. Mibe et al. Phys. Rev. Lett  p -> K + ,  p -> K +  0 M. Sumihama et al. Phys. Rev. C  n -> K +  - H. Kohri et al. Phys. Rev. Lett  p -> p 0 p M. Sumihama et al. Phys. Lett. B  p -> K +  K. Hicks et al. Phys. Rev. C (R) 2008  9.  d ->  d W.C. Chang et al. Phys. Lett. B  p -> K +  (1405),  0 (1385) M. Niiyama et al. Phys. Rev. C Pentaquark search T. Nakano et al. Phys. Rev. C  p -> K +  0 (1385) K. Hicks et al. Phys. Rev. Lett  p -> K +  (1520) N. Muramatsu et al. Phys. Rev. Lett  p -> K +  (1520) H. Kohri et al. arXiv:

Physics motivation We challenge current controversial problems in hadron physics. 1. Hidden strangeness content study via 2. To investigate the bump structure in excitation energy observed in  meson photoproduction. 3. To investigate the bump structure in excitation energy observed in K +  (1520) photoproduction from the proton. 4. Others from the complete polarization observables in photoreactions.

1. Hidden Strangeness Content World data indicating strangeness content in the nucleon Nucleon structure function obtained by the lepton deep inelastic scattering and elastic p scattering indicate that the amount of spin carried by ss is comparable to that carried by u and d quarks. Analysis of  N sigma term suggests proton contains 20% strange quarks. Annihilation pp  X reaction at rest shows strong violation of OZI(Okubo-Zweig-Iizuka) rule.

HERMES semi-inclusive DIS data A.Airapetian et al. Phys. Rev. Lett (2004) Previous data  s ~ K. Abe et al. PRL (1995)  s ~ D. Adams et al. PLB (1994) New Data Strange quark contribution is found to be small.

This simple picture depicts pairs of strange quarks as they pop into and out of existence alongside the permanent quark residents of the proton. Nuclear physicists have found that strange quarks, though present for just tiny fractions of a second at a time, also contribute to the proton's properties. Image: JLab SPIN CRISIS  at least 10% ss content in nucleon G0 experiment at JLAB: Anapole moment Z0Z0 e e  electroweak process nucl-ex/

HAPPEX (JLab) parity violating elastic ep scattering A. Acha et al. Phys. Rev. Lett (2007) Electric strange form factor Magnetic strange form factor

Strange quark distribution A. Airapetian et al. HERMES collaboration PLB 666 (2008) 446 Fig. 3. The strange parton distribution xS(x) from the measured Hermes multiplicity for charged kaons evolved to Q 0 2 = 2.5 GeV 2 assuming for The solid curve is a 3-parameter fit for S(x) = x −0.924 e −x/ (1 − x), the dashed curve gives xS(x) from Cteq6l, and the dot–dash curve is the sum of light antiquarks from Cteq6l.

  meson LEPS of SPring-8 Studying diffractive channels as a tool for non-perturbative QCD (Pomeron structure, search for glueball, f 2 ’-meson trajectories, etc ) Search for exotic processes as ss-knockout Henley et al. [94] Titov, Yang, Oh [94-98 ] Non-polarized observables are not suitable for this study

ss contents in proton ・  -meson: ~ ss  p   p pomeron exchange +  exchange + ss knock-out Study small amplitudes by interference  double polarization asymmetry

Reconstructed  events (K + K - event) Missing mass ( ,K + K - )X (GeV) events /2.5MeV Proton(938)  =10 MeV Invariant mass (K + K - ) (GeV) events /2.5MeV  Invariant mass square (K + K - ) (GeV 2 )  Invariant mass square (K - p) (GeV 2 ) Selections for  event (KK mode) |M(KK)-M  |< 10 MeV |MM(( ,K + K - )X)- M proton |< 30 MeV

Beam-target asymmetry and exotic processes with unnatural parity exchange ( -knockout) ss LEPS, Spring-8 (calculated by Titov) with 1% ss-bar content

Physics motivation 2 To investigate the bump structure found in  meson photoproduction Diffractive  meson photoproduction on proton T. Mibe, W. C. Chang, T. Nakano et al. Phys. Rev. Lett (2005) Bump

Physics motivation 3 To investigate the bump structure found in K +  (1520) photoproduction from the proton Solid curve : with N * by Nam et al. Dashed curve : without N * by Nam et al. Dotted curve : without N * by Titov et al. Comparison with calculations based on effective Lagrangian approach Bump  p → K + X Complete Polarization Observables are needed ! H. Kohri et al. LEPS collaboration arXiv: (2009)

4. Other  p  p   p  p   p  p   p  p    ’  M. Sumihama et al. LEPS collaboration to be submitted.  p  p 

Experimental consideration for complete polarization observables and Instrumentation

Error estimation for C BT measurement

Polarization in thermal equilibrium | -1/2> |+1/2>  E=g  N B If I=1/2, E B=17T T=10mK, Proton polarization 95% Deuteron polarization 70%

Principle of HD Longstanding effort at Syracuse, LEGS/BNL ORSAY mK 15-17T 80% for H, 20% for D (vector) 20%  70% in D with DNP

S. Bouchigny, C. Commeaux, J.-P. Didelez, G. Rouillé, Nucl. Instrum. Meth in Phys. Res. A 544 (2005) 417 When [HD]~99.5; T~500mk; B~1T the relaxation time is about 20 hours.

Polarized HD NMR Coils Solenoid Coil Saddle coils Liquid 3 He (0.5 K) Liquid 4 He (4.2 K) 70 K Shield Al Wires HYDILE

Dilution refrigerator (DRS) Leiden Cryogenics DRS-3000 ( 3 He/ 4 He dilution refrigerator) Cooling power 3000μW at 120 mK Lowest temperature 6 mK

1220mm 170mm 70mm Mixing Chamber Nb3Sn joints & Protection Circuit NbTi joints & Switch Main Coil Correction Coil Null Coil Rough dimensions of the magnet 400mm 600mm 550mm 1K Pot 538mm

Dilution refrigerator (DRS) Superconducting magnet Magnetic Field 17 Tesla Homogeneity of Magnetic Field 5×10 -4 for 15 cm Magnetic Field (Tesla) Y Position (mm) Y axisDRS Magnet Y Position (mm) HD target

HD gas distillation system Pure HD gas of an impurity ~0.01% is needed for obtaining a long relaxation time. HD gas distillation system is still underdevelopment at RCNP

IBC 3 He/ 4 He Dilution Refrigerator Lowest temperature : 250 mK Magnetic field : 1 Tesla Field homogeneity : 5 x for target region

IBC （ In Beam Cryostat ） 2.5cm Al wire 5 cm

TC （ Transfer Cryostat ）

Road map (5 years from 2005 fiscal year) for Studies of Hardron structures （ DR ＋ SC magnet ） 2009After 2010Fiscal year Spin and parity determination of  + particle HD gas 、 IBC 、 TRC 、 others TRC NMR DR+IBC SRC New DR Scintillator ball 、 TPC Scintillator ball Installation of new detectors Roma2, ORSAY HD at Spring-8 、  meson production, K-production, hidden strangness of nucleon New TPC design HD polarization Charged meson production Experiments with magnetic spectrometer Polarized HD  SPring-8 Collaboration with Roma2 、 ORSAY 、 US Neutral particle detection with Scintillator ball total 92,507 kyen 103,000 93,000 New badget 83,505 96,000 86,000 total About 480,000 kyen IBC cryostat and new Data taking system

Summary 1. Physics Motivation of HD project at RCNP/Spring-8 2. C BT measurements with polarized target  +p   + p  +p  K+ , K+   +p   + p etc ….. 3. Present status of HD at RCNP The first trial of the experiment will start from January Your joining is really welcome!