Breakup Reactions of Breakup Reactions of Halo Nuclei Halo Nuclei - PowerPoint PPT Presentation

Breakup Reactions of Breakup Reactions of Halo Nuclei Halo Nuclei T. Sugimoto a), a), * * , , T. Nakamura T. Nakamura a) a) , , N. Fukuda N. Fukuda b) b) , , M. Miura M. Miura a) a) , , T. Sugimoto Y. Kondo a) a) , , N. Aoi N. Aoi b) b) , , H. Baba H. Baba c) c) , , D. Bazin D. Bazin d) d) , , T. Gomi T. Gomi c) c) , , Y. Kondo H. Hasegawa c) c) , , Y. Hashimoto Y. Hashimoto a) a) , , N. Imai N. Imai b) b) , , T. Kobayashi T. Kobayashi e) e) , , H. Hasegawa T. Kubo b) b) , , T. Motobayashi T. Motobayashi b) b) , , M. Ohara M. Ohara a) a) , , A. Saito A. Saito c) c) , , T. Kubo H. Sakurai f) f) , , S. Shimoura S. Shimoura g) g) , , A. M. Vinodkumar A. M. Vinodkumar a) a) , , H. Sakurai e), Y. X. Watanabe h) , e) , K. Watanabe e), Y. X. Watanabe h) , T. Yakushiji T. Yakushiji e) , K. Watanabe Y. Yanagisawa b) b) , , K. Yoneda K. Yoneda d) d) , , and M. Ishihara and M. Ishihara b) b) Y. Yanagisawa a) Tokyo Institute of Technology b) RIKEN c) Rikkyo University ty a) Tokyo Institute of Technology b) RIKEN c) Rikkyo Universi d) NSCL, Michigan State University e) Tohoku University f) University of Tokyo niversity of Tokyo d) NSCL, Michigan State University e) Tohoku University f) U g) CNS, University of Tokyo h) High Energy Accelerator Research Organization h Organization g) CNS, University of Tokyo h) High Energy Accelerator Researc

Neutron Halo Nuclei Neutron Halo Nuclei Two Neutron Halo ( 11 ( 11 Li : Li : 9 9 Li + Li + n n + + n n ) ) 17 B B 17 14 Be Be 14 11 Li Li 11 Borromean Ring ( 11 11 Li : Li : 9 9 Li + Li + n n + + n n ) ) ( 9 Li Li 9 Our Interest Interest Our 11 Li, Li, 14 14 Be, Be, 17 17 B B two neutron halo nuclei: 11 two neutron halo nuclei: n n n n 10 Li, 13 Be, 16 B and these subsystems: 10 Li, 13 Be, 16 B and these subsystems:

Previous Works Previous Works 10 Li Li 13 Be Be Comparison of the Decay Energy of 10 Reported Levels of 13 Comparison of the Decay Energy of Reported Levels of M. Thoennessen et al., Phys. Rev. C 63 63 , 014308 (2000) , 014308 (2000) M. Thoennessen et al., Phys. Rev. C 16 B B Reported Levels of 16 Reported Levels of 2.32(7) 2.32(7) M. Thoennessen et al., Phys. Rev. C 59 59 , 111 (1999) , 111 (1999) M. Thoennessen et al., Phys. Rev. C 0.04(4) 0.04(4) 10 Li Li : results are not matched yet. 10 : results are not matched yet. 13 Be, Be, 16 16 B B : only a few results are reported. : only a few results are reported. 13 Systematic study of the unbound subsystems unbound subsystems . . Systematic study of the R. Kalpakchieva et al., Eur. Phys. J. A 7 7 , 451 (2000) , 451 (2000) R. Kalpakchieva et al., Eur. Phys. J. A

Studies using Breakup Reactions Studies using Breakup Reactions — Nuclear Breakup Nuclear Breakup — Carbon Target (small (small Z ) — Carbon Target Z ) — Neutron Knockout Reaction p neut Invariant mass Invariant mass and and Relative energy Relative energy p ( ) Li 9 ( ) ∑ ∑ 2 = 2 − * M E p ( ) ∑ = − E M * M rel fragment the momentum vectors of of charged fragment charged fragment and and one neutron one neutron the momentum vectors Invariant Mass Method Invariant Mass Method Relative energy spectrum between core + neutron subsystem single particle state of of the unbound subsystem the unbound subsystem single particle state → → Energy level and Configuration of Energy level and Configuration of valence neutron valence neutron

Experimental Facility — — RIPS RIPS Experimental Facility RIKEN KEN RI Projectile rojectile- -Fragment Fragment P E6 Separator eparator S Primary Beam Primary Beam 11 Li, 14 Be : 18 O 100 MeV/nucleon 11 Li, 14 Be : 18 O 100 MeV/nucleon Secondary Beam Secondary Beam SX4 17 17 B : B : 22 22 Ne 110 MeV/nucleon Ne 110 MeV/nucleon SX3 F2 Q7Q8 Q9 F3 Q10Q11Q12 Secondary Beam Secondary Beam D2 Experimental Area Experimental Area Q6 11 Li : 69.0 MeV/nucleon, 11 Li : 69.0 MeV/nucleon, Q5 F1 11 kcps, 90% 11 kcps, 90% SX2 Q4 14 Be : 68.3 MeV/nucleon, 14 Be : 68.3 MeV/nucleon, D1 5.2 kcps, 90% 5.2 kcps, 90% 17 B : 72.7 MeV/nucleon, 17 B : 72.7 MeV/nucleon, SX1 Q3 700 cps, 85% 700 cps, 85% Q2 Q1 Primary Target Primary Target F0 Primary Beam Primary Beam

Experimental Setup Experimental Setup RIPS F3 RIPS F3 Experimental Area Experimental Area Neutron Hodoscope (Plastic Scintillator) Veto Counters Neutron(s) ) Neutron(s Secondary Target Secondary Target 2 ) C (377 mg/cm 2 ) C (377 mg/cm 2 ) (346 mg/cm 2 Pb Pb (346 mg/cm ) Drift Chamber Hodoscope γ - γ -ray ray Charged Fragments Charged Fragments from charged particle from charged particle Drift Chamber 9 Li, 12 Be, 15 B, 9 Li, 12 Be, 15 B, … … NaI(Tl) PPAC Dipole Magnet Secondary Beam Secondary Beam 11 Li, 14 Be, or 17 B 11 Li, 14 Be, or 17 B

Relative Energy Spectrum of 9 9 Li+ Li+ n n Relative Energy Spectrum of s- -wave: wave: s continuum state 10 Li continuum state 10 Li σ 2 d ∫ ψ Ψ 3 * ~ d r ( r ) ( r ) k k 0 dE (overlap integral) (overlap integral) − α exp( r ) ′ Ψ ∝ ( r , r ) r 0 (initial state: Yukawa function Yukawa function ) ) (initial state: + δ sin( kr ) ψ = ( r ) k kr (final state: scattering state scattering state ) ) (final state: δ = − ak + ( 3 O k ) (phase shift) (phase shift) Fitting Parameters Fitting Parameters : scattering length a : scattering length a α : ~ √ (2 µ S α : ~ √ (2 µ c.f. M. Thoennessen et al. -wave: wave: a c.f. M. Thoennessen et al. s - ) 2n ) a < < - -20 fm 20 fm S 2n s Γ = 0.358 MeV , Γ -wave: wave: E p - = 0.538 MeV , E r = 0.358 MeV p r = 0.538 MeV G. F. Bertsch and K. Hencken, Phys. Rev. C G. F. Bertsch and K. Hencken, Phys. Rev. C 57 57 , 1366(1998) , 1366(1998)

Relative Energy Spectrum of 12 12 Be+ Be+ n n Relative Energy Spectrum of s- -wave: wave: s continuum state 13 Be continuum state 13 Be σ 2 d ∫ ψ Ψ 3 * ~ d r ( r ) ( r ) k k 0 dE (overlap integral) (overlap integral) − α exp( r ) ′ Ψ ∝ ( r , r ) r 0 (initial state: Yukawa function Yukawa function ) ) (initial state: + δ sin( kr ) ψ = ( r ) k kr (final state: scattering state scattering state ) ) (final state: δ = − ak + ( 3 O k ) (phase shift) (phase shift) Fitting Parameters Fitting Parameters : scattering length a : scattering length a c.f. M. Thoennessen et al.: s -wave: wave: a c.f. M. Thoennessen et al.: s - a < < - -10 fm 10 fm α : ~ √ (2 µ S α : ~ √ (2 µ ) 2n ) S 2n E ~ 0.2 MeV ~ 0.2 MeV E

Relative Energy Spectrum of 15 15 B+ B+ n n Relative Energy Spectrum of -wave: wave: d - d 16 B resonance state 16 resonance state B d σ Γ ~ − + Γ 2 2 dE ( E E ) 4 r (Breit- -Wigner Wigner eq eq.) .) (Breit Γ = P γ 2 by Sugimoto et al. 2 l l l E r = 0.065 (resonance width) (resonance width) γ = 0.136 5 ( kR ) = P ( kR ) s -wave as a background = + + l 2 2 4 9 3 ( kR ) ( kR ) (penetrability) (penetrability) Fitting Parameters Fitting Parameters r : resonance energy : resonance energy E r E γ : reduced width γ : reduced width = 0.07 MeV, γ γ = 0.14 A low- -lying lying d -state is observed. state is observed. E A low d - E r = 0.14 r = 0.07 MeV, c.f. R. Kalpakchieva et al.: c.f. R. Kalpakchieva et al.: E E = 0.04(6) MeV = 0.04(6) MeV

Further Analysis: Three- -body Relative Energy body Relative Energy Further Analysis: Three Lead Target : : Lead Target 11 Li 11 Li Coulomb Breakup Coulomb Breakup y y r r a a n n Three- -body body Three i i m m i i l Invariant- -mass mass Invariant l e e r r P P Low- -lying lying Low E1 strength E1 strength

Summary Summary 11 Li, 14 Be, and 17 B, � Studies of Studies of 11 Li, 14 Be, and 17 B, � using the Nuclear Breakup Nuclear Breakup reaction reaction using the � Investigation of the Investigation of the single particle state single particle state � of unbound subsystems ( 10 10 Li, Li, 13 13 Be, Be, 16 16 B) B) of unbound subsystems ( � Invariant Invariant- -mass Spectroscopy mass Spectroscopy � 10 Li, Li, 13 13 Be : Be : s -wave continuum state wave continuum state � 10 s - � 16 B : 16 B : d -wave resonance state wave resonance state d - — a a candidate candidate of the ground state of the ground state — � Further analysis: Further analysis: Three Three- -body Relative Energy body Relative Energy � with Nuclear / Coulomb Breakup reactions with Nuclear / Coulomb Breakup reactions

Collaborators Collaborators Tokyo Institute of Technology Tokyo Institute of Technology T. Nakamura, M. Miura, Y. Kondo , A. M. Vinodkumar, T. Nakamura, M. Miura, Y. Kondo , A. M. Vinodkumar, Y. Hashimoto, M. Ohara Y. Hashimoto, M. Ohara RIKEN RIKEN N. Fukuda, N. Aoi, N. Imai, T. Kubo, T. Motobayashi, N. Fukuda, N. Aoi, N. Imai, T. Kubo, T. Motobayashi, Y. Yanagisawa, M. Ishihara Y. Yanagisawa, M. Ishihara Rikkyo University Rikkyo University H. Baba, T. Gomi, H. Hasegawa, A. Saito H. Baba, T. Gomi, H. Hasegawa, A. Saito NSCL, Michigan State University NSCL, Michigan State University D. Bazin, K. Yoneda D. Bazin, K. Yoneda Tohoku University Tohoku University T. Kobayashi, K. Watanabe, T. Yakushiji T. Kobayashi, K. Watanabe, T. Yakushiji University of Tokyo University of Tokyo H. Sakurai, S. Shimoura H. Sakurai, S. Shimoura High Energy Accelerator Research Organization (KEK) High Energy Accelerator Research Organization (KEK) Y. X. Watanabe Y. X. Watanabe