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 Few-body physics in nuclei Real photon beams for nuclear experiments Topics from recent experimental studies Application to nuclear astrophysics Summary Outline

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, 2 , 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

Two-body system Equation of Motion--- analytically solvable  exact solution Observables; nucleon-nucleon scattering, p(n,  )d (d( ,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;  2 /d.o.f. =1~2

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

D( ,n)p cross section data overall uncertainty < 0.9% !

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

3NF Binding energies of A=3 * Energy threshold relative to 3 H+p Nuclear potentials E bin [MeV]E th [MeV] * 3H3H 3 He 3 He-nd-d AV AV18+UIX AV18+UIX+V3* Exp H.M. Hofmann and G.M. Hale, PRC68 (2003) R

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

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

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/  ) expansion,  ~800MeV) etc... Most of the above give consistent results on g.s. of 4 He. But...

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

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

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

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

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

Laser Compton backscattering Relativistic electron (E e ) Laser light ( L )  (E  ) E  (  ) ex. L =1.064  m, E e =800MeV ⇒ E  = 11MeV  Angular dependence Klein-Nishina formula

Advantages of LCS-  Quasi-monochromatic;  E/E ~ a few % Little background  -rays; tagging not necessary Well-collimated;  < 0.1 mrad Highly polarized; linear or circular, P ~ 100% Continuous or pulsed;  t < 10ns Considerable intensity;   =10 4 ~ 10 8  /s/MeV

LCS  -ray facilities in the world YearFacility E e [GeV] Laser E  [MeV]   [/sec/MeV] 1964Lebedev0.6ruby~10~ Harvard / CEA6ruby~10005× Frascati / LADON1.5Ar + 5 – 80~ ETL(AIST) / TERAS Nd-YAG2 – ~ BNL / LEGS2.8Nd-YAG150 – ~ Grenoble / GrAAL6Ar ~ 4× SPring-8 / LEPS8Ar – 3500~ TUNL(Duke) / HI  S FEL2 – ~ LASTI(U. Hyogo) / NewSUBARU Nd-YVO 4, CO 2, CO 1.7 – ~ 10 6

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

NewSUBARU/LCS-  source Linac e - E e =1.0GeV E  = MeV,   =10 4~5 photons/MeV/s,  E  /E  =3~10% K. Aoki, S. Miyamoto, et al. NIM A516 (2004)  accelerated to 1~1.5GeV

Experiment with quasi-monochromatic  at NewSUBARU Laser Compton-scattered  -ray : E  = 16 ~ 40MeV,    ~2×10 4 /sec, FWHM~9%, P~100%

Time Projection Chamber Operational gas; He+CD 4 (active target) →  ~ 4 ,   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( ,p)n)

Event Identification 4 He( ,p) 3 H 4 He( ,n) 3 He 4 He photodisintegrations

Backgrounds  from natural RI Photoelectrons

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

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

4 He( ,n) 3 He (preliminary) ●○ RCNP-AIST2005 (PRC72, ) ; =351nm (3rd), E e =0.8GeV ● RCNP-NewSUBARU; =532nm (2nd), E e =0.97MeV ● RCNP-NewSUBARU; =1064nm (fund.), E e ≤1.46GeV ○ RCNP-NewSUBARU; =532nm (2nd), E e =1.06GeV ● Lund (PRC75, ) ; tagged photons

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

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

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

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

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

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

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  --- quasi-monoenergy, little background, high polarization  Precise data on cross section, branching ratio, angular distribution, analyzing power,...

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