1 / 41

Photoreactions with Polarized HD target at SPring-8

Photoreactions with Polarized HD target at SPring-8. M. Fujwawa@EMI2009 19 September 2009, Moscow. 1. SPring-8 Facility 2. Physics Motivation 3. HD projects: Polarized proton and deuteron target: HD target project for complete polarization observables. Collaborators of HD project.

giles
Download Presentation

Photoreactions with Polarized HD target at SPring-8

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. Photoreactions with Polarized HD target at SPring-8 M. Fujwawa@EMI2009 19 September 2009, Moscow 1. SPring-8 Facility 2. Physics Motivation 3. HD projects: Polarized proton and deuteron target: HD target project for complete polarization observables.

  2. 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)

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

  4. Back Compton Scattering Energy of BCS photons b : Electron velocity /c qL: Incident angle of laser photon q : Scattered angle of photon Scattered electrons Head-on collision (qL=0) Incident Photons El Incident electrons Ee q Scattered photons Eg ex. Ee=8 GeV, (Laser l=351 nm) Back Compton scattering 2.4 GeV Maximum

  5. LEPS facility Collision 8 GeV electron Recoil electron Electron tagging a) SPring-8 SR ring Laser light b) laser hutch c) experimental hutch Inverse Compton g-ray M. Fujiwara, Nuclear Physics News 11 (2001) 28-32.

  6. Laser System Energy spectrum 351 nm 257 nm • 351 nm Ar laser • （multi-line UV, 4 W） • 106 photons/sec on target • Linearly polarized laser beam • Polarized LEP beam • ~95% at 2.4 GeV tagged Linear Polarization 351 nm 257 nm tagged

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

  8. Missing mass spectrum • p(g,K+)L (1116) • p(g,K+)S0 (1193) • 1.5 ~ 2.4 GeV • 0.6 < cosqcm < 1 Photon beam asymmetry

  9. Photon beam asymmetry S R. Zegers et al., Phys. Rev. Lett. 91 (2003) 092001. M. Sumihama et al., C 73 (2006) 035214. H. Kohri et al., Phys. Rev. Lett. 97 (2006) 082003. N : K+ photoproduction yield F : K+ azimuthal angle Pg: Polarization of photon n : Normalization factor for Nv For all events

  10. LEPS experiments (2000 – 2009)

  11. Published Papers from LEPS@SPring-8(Results from polarization observables in Red) 2003 1. gp -> K+Lgp -> K+S0 R. G. T. Zegers et al. Phys. Rev. Lett. 91 092001 2. Pentaquark search T. Nakano et al. Phys. Rev. Lett. 91 012002 2005 3. f meson production Li, C, Al, Cu T. Ishikawa et al. Phys. Lett. B 608 215 4. f meson production proton target T. Mibe et al. Phys. Rev. Lett. 95 182001 2006 5. gp -> K+L, gp -> K+S0 M. Sumihama et al. Phys. Rev. C 73 035214 6. gn -> K+S- H. Kohri et al. Phys. Rev. Lett. 97 082003 2007 7. gp -> p0p M. Sumihama et al. Phys. Lett. B 657 32 8. gp -> K+L K. Hicks et al. Phys. Rev. C 76 042201(R) 2008 9. gd -> fd W.C. Chang et al. Phys. Lett. B 658 209 10. gp -> K+L(1405), S0(1385) M. Niiyama et al. Phys. Rev. C 78 035202 2009 11. Pentaquark search T. Nakano et al. Phys. Rev. C 79 025210 12. gp -> K+S0(1385) K. Hicks et al. Phys. Rev. Lett. 102 012501 13. gp -> K+L(1520) N. Muramatsu et al. Phys. Rev. Lett. 103 012001 14. gp -> K+L(1520) H. Kohri et al. arXiv:0906.0197

  12. 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 f meson photoproduction. 3. To investigate the bump structure in excitation energy observed in K+L(1520) photoproduction from the proton. 4. Others from the complete polarization observables in photoreactions.

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

  14. HERMES semi-inclusive DIS data Previous data Ds ~ -0.10 +- 0.04 K. Abe et al. PRL 74 346 (1995) Ds ~ -0.12 +- 0.04 D. Adams et al. PLB 329 399 (1994) New Data Strange quark contribution is found to be small. • Airapetian et al. • Phys. Rev. Lett. • 92 012005 (2004)

  15. G0 experiment at JLAB: Anapole moment e nucl-ex/0506021 electroweak process g Z0 e 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 http://www.jlab.org/div_dept/dir_off/public_affairs/news_releases/2005/gzero.html

  16. HAPPEX (JLab) parity violating elastic ep scattering Electric strange form factor A. Acha et al. Phys. Rev. Lett. 98 032301 (2007) Magnetic strange form factor

  17. Strange quark distribution Fig. 3. The strange parton distribution xS(x) from the measured Hermes multiplicity for charged kaons evolved to Q 02= 2.5 GeV2 assuming The solid curve is a 3-parameter fit forS(x) = x−0.924e−x/0.0404(1 − x), the dashed curve gives xS(x) from Cteq6l, and the dot–dash curve is the sum of light antiquarks from Cteq6l. A. Airapetian et al. HERMES collaboration PLB 666 (2008) 446

  18. f-meson photoproduction @ LEPS of SPring-8 Studying diffractive channels as a tool for non-perturbative QCD (Pomeron structure, search for glueball, f2’-meson trajectories, etc ) Non-polarized observables are not suitable for this study Search for exotic processes as ss-knockout Henley et al. [94] Titov, Yang, Oh [94-98]

  19. ss contents in proton ・　f-meson: ~ ss g pf p pomeron exchange + p exchange + ss knock-out Study small amplitudes by interference  double polarization asymmetry

  20. Reconstructed fevents (K+K- event) Proton(938) f(1019) events /2.5MeV events /2.5MeV s =10 MeV Missing mass (g,K+K-)X (GeV) f Invariant mass (K+K-) (GeV) Invariant mass square (K+K-) (GeV2) Selections for f event (KK mode) |M(KK)-Mf |< 10 MeV |MM((g,K+K-)X)- Mproton|< 30 MeV Invariant mass square (K-p) (GeV2)

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

  22. Physics motivation 2To investigate the bump structure found in f meson photoproduction Diffractive f meson photoproduction on proton Bump T. Mibe, W. C. Chang, T. Nakano et al. Phys. Rev. Lett. 95 182001(2005)

  23. Physics motivation 3To investigate the bump structure foundin K+L(1520) photoproduction from the proton gp → K+X H. Kohri et al. LEPS collaboration arXiv: 0906.0197 (2009) Bump Comparison with calculations based on effective Lagrangian approach Bump Solid curve : with N* by Nam et al. Dashed curve : without N* by Nam et al. Dotted curve : without N* by Titov et al. Complete Polarization Observables are needed !

  24. 4. Other gp  p p p gp  p p p p gp  p p p p p gp  p p0/h/h’/w gp  p h M. Sumihama et al. LEPS collaboration to be submitted.

  25. Experimental consideration for complete polarization observables and Instrumentation

  26. Error estimation for CBT measurement

  27. Polarization in thermal equilibrium E Ｂ If I=1/2, | -1/2> DE=gmNB |+1/2> B=17TT=10mK, Proton polarization 95% Deuteron polarization 70%

  28. Principle of HD • Longstanding effort at Syracuse, LEGS/BNL ORSAY • 10-20 mK • 15-17T • 80% for H, 20% for D (vector) • 20%70% in D • with DNP

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

  30. HYDILE target @Orsay 70 K Shield Liquid 4He (4.2 K) Saddle coils Al Wires PolarizedHD NMR Coils Liquid 3He (0.5 K) Solenoid Coil

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

  32. 1K Pot 1220mm 538mm Mixing Chamber Null Coil 170mm 70mm Correction Coil 550mm Main Coil NbTi joints & Switch Nb3Sn joints & Protection Circuit 600mm Rough dimensions of the magnet 400mm

  33. Dilution refrigerator (DRS)Superconducting magnet Y axis DRS Magnetic Field17 Tesla Homogeneity of Magnetic Field5×10-4 for 15 cm Magnetic Field (Tesla) Magnetic Field (Tesla) HD target Y Position (mm) Y Position (mm) Magnet

  34. 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

  35. IBC 3He/4HeDilution Refrigerator Lowest temperature : 250 mK Magnetic field : 1 Tesla Field homogeneity : 5 x 10-4 for target region

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

  37. TC（Transfer Cryostat）

  38. Road map (5 years from 2005 fiscal year) for Studies of Hardron structures Fiscal year 2005 2006 2007 2008 2009 After 2010 Charged meson production Experiments with magnetic spectrometer （DR＋SC magnet） Collaboration with Roma2、ORSAY、US HD gas、IBC、TRC、others Spin and parity determination of Q+ particle HD at Spring-8、f-meson production, K-production, hidden strangness of nucleon IBC cryostat and new Data taking system Roma2, ORSAY Neutral particle detection with Scintillator ball TRC NMR DR+IBC SRC New DR HD polarization Polarized HD  SPring-8 New TPC design Scintillator ball、TPC Installation of new detectors Scintillator ball total About 480,000 kyen 92,507 kyen total 103,000 103,000 93,000 93,000 83,505 New badget 96,000 96,000 86,000 86,000

  39. Summary 1. Physics Motivation of HD project at RCNP/Spring-8 2. CBTmeasurements with polarized target g+pf + p g+pK+L, K+S g+p h + p etc ….. 3. Present status of HD at RCNP The first trial of the experiment will start from January 2010. Your joining is really welcome!

More Related