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Tatsushi Shima Research Center for Nuclear Physics, Osaka University, Japan

The 4th Yamada Symposium on Advanced Photons and Science Evolution 2010 (APSE2010) June 14-18, 2010, Osaka Japan. Laser MeV Photons and Few-body Physics. Tatsushi Shima Research Center for Nuclear Physics, Osaka University, Japan. Outline. Few-body physics in nuclei

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Tatsushi Shima Research Center for Nuclear Physics, Osaka University, Japan

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  1. The 4th Yamada Symposium on Advanced Photons and Science Evolution 2010 (APSE2010) June 14-18, 2010, Osaka Japan Laser MeV Photons and Few-body Physics Tatsushi Shima Research Center for Nuclear Physics, Osaka University, Japan Outline • Few-body physics in nuclei • Real photon beams for nuclear experiments • Topics from recent experimental studies • Application to nuclear astrophysics • Summary

  2. Few-body Physics in Nuclei Nucleus; a system of a finite number of strongly interacting particles (nucleons) Potential; nuclear forces (strong interaction)  exchange of one pion, 2p, heavy meson, ... non-central; tensor, many-body force, ... charge-independence breaking (CIB), charge-symmetry breaking (CSB), etc. Equation of Motion; no general solution for N>3 systems, perturbation (expansion by coupling const.) useless

  3. Two-body system Equation of Motion--- analytically solvable  exact solution Observables; nucleon-nucleon scattering, p(n,g)d (d(g,p)n ) Nucleon-nucleon (NN) potential; E.M. OPE residual A few tenth of parameters are adjusted to 2000~4000 data of pp and pn scattering in 0~350MeV. Accuracy; c2/d.o.f. =1~2

  4. Phase parameters for J≤4 in pp scattering (CD-Bonn2001) R. Machleidt, Phys. Rev. C63, 024001 (2001)

  5. D(g,n)p cross section data overall uncertainty < 0.9% !

  6. Three-body system numerically exact solution by Faddeev method  check nuclear potentials in three-body system • Ground-state properties of 3H and 3He; binding energy, D-state probability, magnetic moment,... • Scattering; d(p,p)d, d(n,n)d • Radiative capture; d(p,g)3He, d(n,g)t • Photodisintegration; 3He(g,p)d, 3He(g,pn)p Three-nucleon force (3NF)

  7. 3NF H.M. Hofmann and G.M. Hale, PRC68 (2003) 021002R • Binding energies of A=3 * Energy threshold relative to 3H+p

  8. Scattering pd-elastic at RIKEN & RCNP K. Sekiguchi et al., PRL 95, 162301 (2005) NN+3N NN only

  9. Experiment S. Naito et al. PRC73, 034003 (2006) Faddeev (AV18) Faddeev (AV18+Urbana-IX) 3He photodisintegration (3NF) 3NF makes better, but not enough.

  10. Four-body system Various methods are proposed to solve 4N-EoM; Faddeev-Yakbovsky method (FY) Alt-Grassberger-Sandhas formalism (Faddeev-AGS) No-core shell model (NCSM) Effective interaction hyperspherical harmonics (EIHH) Cluster model Chiral perturbation theory ((Q/L) expansion, L~800MeV) etc... Most of the above give consistent results on g.s. of 4He. But...

  11. Calculation for 4He(g,n)3He cross section Trento (Effective Interaction Hyperspherical Harmonics) Bonn (Faddeev-AGS) Londergan and Shakin (Coupled Channel Shell Model) Horiuchi and Suzuki (Cluster model)

  12. Previous works; 4He(g,p)3H & 3H(p,g)4He (detailed balance) PRC72, 044004 (2005) ◆ Gorbunov 62 ▼ Arkatov 78 ▲ Bernabei 88 ■ Hoorebeke 93 ＋ Gardner 62 × Gemmell 62 ◇ Meyerhof 70 △ McBroom 82 ▽ Calarco 83 ○ Feldman 90 □ Hahn 95 (g,p) (p,g)

  13. Previous works; 4He(g,n)3He & 3He(n,g)4He (detailed balance) ◆ Gorbunov 62 ▲ Berman 71 ■ Malcom 73 ▼ Irish 73 ● Nilsson2005 △ Ward 81 ○ Komar 93 (g,n) (n,g) ● RCNP-AIST, PRC72, 044004 (2005) No other tracking measurement with monochromatic g-rays.

  14. Low-energy g-ray sources • Discrete g-rays from radioisotopes • Bremsstrahlung (continuous energy) / tagged photons • e+e- pair annihilation in flight ; monoenergy g + brems. • Laser Compton Scattered g (LCS-g)

  15. Energy distributions of g-ray beams Bremsstrahlung, e+e- annihilation in flight Laser Compton-Scattered g (PH spectra of GSO scintillator) BG from low-energy component of brems. (almost) no BG !!

  16. Laser Compton backscattering Relativistic electron (Ee) Laser light (lL) Angular dependence g (Eg) Klein-Nishina formula Eg(q) ex. lL=1.064mm, Ee=800MeV ⇒ Eg = 11MeV q

  17. Advantages of LCS-g • Quasi-monochromatic; DE/E ~ a few % • Little background g-rays; tagging not necessary • Well-collimated; Dq < 0.1 mrad • Highly polarized; linear or circular, P ~ 100% • Continuous or pulsed; Dt < 10ns • Considerable intensity; Fg=104 ~ 108g/s/MeV

  18. LCS g-ray facilities in the world

  19. NewSUBARU Lab. of Adv. Sci. and Tech. for Industry, University of Hyogo, Japan

  20. NewSUBARU/LCS-g source K. Aoki, S. Miyamoto, et al. NIM A516 (2004) 228-236 Linac e- Ee=1.0GeV  accelerated to 1~1.5GeV Eg =16 - 40 MeV, Fg =104~5 photons/MeV/s, DEg/Eg =3~10%

  21. Experiment with quasi-monochromatic gat NewSUBARU Laser Compton-scattered g-ray : Eg = 16 ~ 40MeV, Fg~2×104 /sec, FWHM~9%, P~100%

  22. Time Projection Chamber • Operational gas; He+CD4(active target) → W ~ 4p , e 100%, little uncertainty in detector sensitivity •track shape, dE/dx → reliable event ID • capability to simultaneous measurements of two-body and multi-body reaction channels as well as the reference reaction (d(g,p)n)

  23. Event Identification 4He photodisintegrations 4He(g,p)3H 4He(g,n)3He

  24. Backgrounds Photoelectrons a from natural RI

  25. D(g,p)n --- Good agreement with existing data as well as theoretical calculations and fittings !

  26. 4He(g,p)3H (preliminary) ●○ RCNP-AIST2005 (PRC72, 044004) ; l=351nm (3rd), Ee=0.8GeV ● RCNP-NewSUBARU; l=532nm (2nd), Ee=0.97GeV ● RCNP-NewSUBARU; l=1064nm (fund.), Ee≤1.46GeV ○ RCNP-NewSUBARU; l=532nm (2nd), Ee=1.06GeV

  27. 4He(g,n)3He (preliminary) ●○ RCNP-AIST2005 (PRC72, 044004) ; l=351nm (3rd), Ee=0.8GeV ● RCNP-NewSUBARU; l=532nm (2nd), Ee=0.97MeV ● RCNP-NewSUBARU; l=1064nm (fund.), Ee≤1.46GeV ○ RCNP-NewSUBARU; l=532nm (2nd), Ee=1.06GeV ● Lund 2005-2007 (PRC75, 014007) ; tagged photons

  28. Comparison with theory ： 4He(g,n)3He ●○RCNP-AIST ●●○RCNP-NewSUBARU ●Lund 2005-2007 Trento (Effective Interaction Hyperspherical Harmonics) Bonn (Faddeev-AGS) Londergan-Shakin (Coupled Channel Shell Model) Horiuchi, Suzuki (Cluster model)

  29. Application to Nuclear Astrophysics Studies • Big Bang nucleosynthesis p(n,g)d, d(p,g)3He, 3H(a,g)7Li, 3He(a,g)7Be, … • H- and He-burnings in stars d(p,g)3He, 12C(p,g)13N, 13C(p,g)14N, 14N(p,g)15O, ... 4He(2a,g)12C, 12C(a,g)16O, ... • s-process (n,g) on heavy nuclei (production) (n,g) on light nuclei (neutron poison) • r-, p-, rp-, g-processes (p,g), (n,g), (g,x)

  30. Neutrino-nucleus interactions in astrophysics Trajectories of Mass Elements in core-collapse SNe n Shock stalls at t~100ms, r~100km n Core bounce rc ~ 1014 g/cc Tc ~ 5 MeV Shock wave n-heating Sumiyoshi et al., ApJ 629 (2005) 922

  31. n-heating; energy transfer by n-A interaction 1051 erg Janka-Müller, A&A 306 (1996) 167 3~12% increase in neutrino luminosity will make it.

  32. Isotopic composition of post-bounce supernova core M=15M☉, 150ms after bounce 4He D Sumiyoshi & Röpke (2008)

  33. Analogy between n-A and g-A interactions Weak operators (neutral current) ; EM operators ; --- Photon is a useful probe for weak nuclear responses.

  34. Summary • Photonuclear reactions provide unique tools for experimental studies of few-nucleon systems; · 3NF(, 4NF?), tensor force, CIB, CSB, ... · theoretical approach to solve N-body EoM • They are also useful to obtain nuclear data demanded for nuclear astrophysics; · radiative capture, neutrino-nuclear reactions • New real-photon source; Laser Compton Scattered g --- quasi-monoenergy, little background, high polarization  Precise data on cross section, branching ratio, angular distribution, analyzing power, ...

  35. Collaborators Y. Nagai Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency H. Utsunomiya, H. Akimune Department of Physics, Konan University T. Mochizuki, S. Miyamoto, K. Horikawa Laboratory for Advanced Science and Technology for Industry, University of Hyogo T. Hayakawa, T. Shizuma Kansai Photon Science Institute, Japan Atomic Energy Agency M. Fujiwara Research Center for Nuclear Physics, Osaka University

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