RIKEN Lecture January 6, 2006 Coherent - Coupling in Neutron-rich Hypernuclei Yoshinori AKAISHI
Exotics? The exotic nucleus, 11 Li
The overbinding problem H -0.1 MeV H He 1 + -0.99 MeV 1 + -1.2 MeV 5 He 0 + -2.0 MeV 0 + -2.9 MeV (Exp) -.12 MeV R.H. Dalitz, R.C. Herndon & Y.C. Tang, Nucl. Phys. B7 (1972) 109 Overbound
Singlet interaction is more attractive than triplet interaction.
Central YN interaction Pictures 1-channel 2-channel D0 D2 N Coupling N A.R. Bodmer (1966) Phase-equivalent to Nijmegen D 0 N phase shift S 1 20 1 S 0 0 0 20 0 (MeV)
Two pictures N int. D0 Overbinding problem N-N int. D2 Underbinding problem H He 5 He H He 5 He -0.1-0.1 Underbinding? 0+ -2.9 Exp -.12 MeV 0+ -2.9 MeV Exp -.12? Overbinding N N N V N, N Q V e N, N Pauli suppression R.H. Dalitz et al. (1972)
Coherent - coupling T=0 T=1 1116 MeV/c 2 119 MeV/c 2
(MeV) 0 He D2 interaction 20 U ( 0 + ) 10 U ( 1 + ) 1 + -1.0 0 + -1.0-1.0 1 + -1.2 0-10 U ( + 0 ) U ( + 1 ) -2.27 0 + -2.9 MeV Exp -20 0 1 2 r (fm) Y. Akaishi, T. Harada, S. Shinmura and Khin Swe Myint, Phys. Rev. Lett. 8 (2000) 59
= = = 1 0 1 0 1 2 p n n s s s = = = + + 1 0 1 0 1 2 n p p s s s H 1 + 0 + S=1 pairs Contribution to U - coupling energy 1 : 9 1/2 /2 +1/2 +1/2 +1/2 +1/2 +1/ -1/ Cancel Coherently added
The 0 + -1 + difference is not a measure of N spin-spin interaction. B. Gibson (Maui, 199) N N (MeV) 0.0 1 + -1.2-1.0-1.0 1 + -1.0-1.20-1.52 He 1 + -1.21-0.68-1. 1 + -0.7 N N -0.06-0.07 1 + -0.97-2.10-2.18-2.9-2.27 0 + 0 + 0 + 0 + -2.51 P coh =1.9 % 0 P coh =0.7 % + P coh =0.9 % P coh =2.0 % Exp D2 SC97e(S) SC97f(S) SC89(S) Th.A. Rijken Y. Akaishi, T. Harada, S. Shinmura & Khin Swe Myint, Phys. Rev. Lett. 8 (2000) 59
CRC
Faddeev-Yakubovsky calculation of He Real space SC97e 1 E E P V V V + V V V V + V A. Nogga, (2001) 0 + 1 + 1.57% 1.08% -5.0-1. -0. -5.90-0.12-0.17-0.0 1.16 1.18-11.98-9.6 1.55 2.00-1.6 (MeV) -1.9-10.08 1 + 1 1 5 V ( E) + V ( E) 0 + 2 2 Model space N 2 N 1 ( E) ( E) V N + V N 2 Is the 1 S 0 YN int. more attractive than the S 1 YN int.? No! Is there any evidence for coherently enhanced - coupling in 0 +? No!
Single-channel description of He Model space SC97e (MeV) 0 + 1 + 1 E V sc V, sc -5.8-1.5-5.7-0.09-0.02-1.7 E V sc V, sc 1.18-6.09 -.91 1.57-6.89-5.2 Coherently enhanced x/5 -.1 Cooking! 1 S 0 sc S 1 is more attractive than. sc V, V + V + sc = V P + V { T + P ΔM } { T } + 1 P = 1 1 P V
Stochastic variational calculation of 5 He H. Nemura, Y. Akaishi & Y. Suzuki, Phys. Rev. Lett. 89 (2002) 1250 The first successful ab initio 5-body calculation including degrees of freedom J.A. Carlson, AIP Conf. Proc. 22 (1991) 198 SC89: unbound H -0.10 [0.15%] -0.1 H -0.92 [0.98%] -0.99 5 He SC97e(S) NN:GRS -2.0-2.06 [1.9%] p -2.75 [1.55%] -.12 (MeV)
Rearrangement of He due to sticking α -28 MeV - MeV -2 MeV -8 MeV Rearrangement in α M. Kohno et al., Phys. Rev. C68 (200) 002 H. Nemura et al., Phys. Rev. Lett. 89 (2002) 1250 N (D) N N P D (α)=10.2% 9.% 1 C V ( E) V ( T E) N V T π (S) N C V ( E) - MeV, MeV, V T π T = 85 MeV N
Repulsion? Attraction? Y. Nogami et al. Nucl. Phys. B19 (1970) 9 N N Y. Akaishi et al. Phys. Rev. Lett. 8 (2000) 59 H He 5 He H He 5 He -0.1-0.1 Underbinding 0 + -2.9 Exp 0 + -2.9 MeV -.12 MeV -.12 An extraordinary state Overbinding
5 He Single channel n n n p p n n p p n 0 p n n Attractive n n p n p n p n p Repulsive Nogami s BF n p
He Single channel n p p n p p n p p 0 p n n Attractive n n p p p n p p 0 n p n p n p Attractive Akaishi s BF Repulsive Nogami s BF
Effects of NN three-body force 0.0 (MeV) He 5 He 1 + 0 + -2.10 Exp 1 + -1.7-1.0-1.2-2.0-2.9 0 + Exp -.12 p p 0 Origin of overbinding Restoration of Pauli principle Coherent - coupling -5.9 Essential dynamics in T=0 nuclei
Three-body force due to coherent - coupling : [for D0] U α r r 1 r r r = W 1 2 α α 1 2 α 1 α= tt, ts, ss 2 ( r, r ) a + b ( σ σ ) + c σ ( σ + σ ) NN 2 NN spin-spin a a a tt ts ss W 7 b tt ctt 16 16 8 1 1 1 bts cts = 8 8 b ss css 5 1 1 8 8 8 t 1 t r, r ' ) = VN, N( r ) VN, ΔM * tt ( N ( r ' ) V t V t 5 He H(1+ ) H(0 + ) H 1 2 ( β ) W tt 2 + MeV 1 2 ( 9 + 2β + β ) W tt 8 1 2 ( 6β + 5β ) W tt 8 1 2 ( 1 6β + β ) W tt 8 s 5 t 1.0 MeV -0. MeV -0.05 MeV VN, N = β VN, N, β = 0.67
Light hypernuclei A.R. Bodmer & Q.N. Usmani, Nucl. Phys. A77 (1988) 621 R. Sinha & Q.N. Usmani, Nucl. Phys. A68 (2001)586c V N 1 r r 2 = ( Vcore( r ) V )( 1 ε + εpx ) + VσσσN Tπ ( r ) Spin-spin DS 2 2 1 r r r V NN = W0Tπ ( r i ) Tπ ( r j ) 1+ σ( σ i + σ j ) 6 Spin-spin H 5 He π N 2 N 1 0 + -1 + splitting 0.8 + 0.86 MeV (70%) The major part is attributed to NN and not to N. 1 + 0 + -1.08 MeV Exp -2.28 MeV -.0 MeV 0.56 + 0.92 (62%) MeV for SC97f Variational Monte Carlo J. Lomnitz-Adler, V.R. Pandharipande & R.A. Smith, Nucl. Phys. A61 (1981) 99
The first observation of a bound state E167 : Phys. Lett. 21 (1989) 55 R.S. Hayano T. Ishikawa M. Iwasaki H. Outa E. Takada H. Tamura A. Sakaguchi M. Aoki T. Yamazaki
Nucleus, He T. Harada, S. Shinmura, Y.Akaishi & H. Tanaka, Nucl. Phys. A507 (1990) 715 100 (MeV) U nucl r r = V + V T t 0 τ nucl Lane term 50 U =V 0 h 0 U t + h 0 T - t + t + 0 2 R (fm) -50 1 U + = V 2 τ 0 h -t
Observation of a He bound state T. Nagae, R.E. Chrien et al., Phys. Rev. Lett. 80 (1998) 1605 He B + =. ± 0. ± 1MeV Γ = 7. 0 ± 0. 7 + 1. 2 0. 0 MeV.6 MeV 7.9 MeV T. Harada, Y.Akaishi et al., Nucl. Phys. A507 (1990) 715
Theory: T. Harada, Phys. Rev. Lett. 81 (1998) 5287
Neutron-excess hypernuclei 0 0 0 p 1 V t 0 p 1 t ( V +V 12 s ) Proton induced Cancellation due to isospin selection n n Neutron induced 1 V t 1 12 t ( V +V s )
Incoherent + n p n p Coherent T T + 1 for T = T z = N 2 0 + 0 coh =/ 0 n p n p n p
SC89 S. Shinmura et al.
Relativistic mean field model Baryons: n, p,, Mesons: σ, ρ, ω X X Coherent - mixing X Normal state of infinite matter Baryons in the medium carry the same quantum numbers in vacuum. N.K. Glendenning, Astrophys. J. 29 (1985) 70.
C58 AD1181
1 H ( 6 He, 2 He ) 5 H 1.7 (MeV) Superheavy hydrogen A.A. Korsheninnikov et al, Phys. Rev. Lett. 87 (2001) 092501 0.0 H H + + 2n 2n+ -. MeV -2.0 H + 2n -.1-1. MeV NN force 6 Li ( π -, K + ) 6 H Hyperheavy hydrogen Khin Swe Myint & Y. Akaishi, Prog. Theor. Phys. Suppl. 16 (2002) 599 7 H 8 H H.I.
Double-charge & strangeness exchange reaction E521 @KEK P.K. Saha, T. Fukuda 10 B ( π -,K + ) 10 Li = 6 H + α = H + 2n + α Stabilizer 11 B ( π -,K + ) 11 Li n 9 Li C. Kurokawa et al.
10 B(π -,K + ) spectrum J-PARC P.K. Saha, T. Fukuda et al., Phys. Rev. Lett. 9 (2005) 952502 P.K. Saha et al., KEK-PS-E521 collaboration Preliminary!! ~0 counts
10 Li 1 - -12.09 2 - D2 int. -12.11-12.17 NN force 0.21 MeV -12.28 (P coh =0.1%) γ 2-1 - SVM cal. beyond -body model α + t + + n + n Coherent - coupling BHF cal. Y. A. & K.S. Myint
0 Y- [ NNN ] T=1/2 : interactions from D2 0 20 U ( 0 + ) Coherent - coupling 10 U ( + 1 ) 0 U ( 1 + ) 1 2 r (fm) 5-10 U ( + 0 ) -20 U ( + 1 ) -0 (MeV) + U ( 0 ) T = 1/ 2 H formation San Dar Myint Oo
Coupling scheme n - Coherent - coupling H formation α formation h n-n 0 -p - coupling n 0 p - n 0 p - t t n n Participant Spectator t α
Coupling scheme of t-t- - 0 H formation h t t t Coherent - coupling t t
7 He t + t + H + t [MeV] 12.1 10.28 7. 0.98 0.0-2.1-2.1 α + n + n + 5 He + n + n 6 He + n 6 He +
J-Lab O. Hashimoto et al. 7 He t + t + H + t [MeV] 12.1 10.28 7. Feshbach resonance? 6 He +
Hyperon mixing in 5 H H. Nemura et al.
Fully coupled channel (-NΞ--) calculations H. Nemura, S. Shinmura, Y. Akaishi & K.S. Myint, Phys. Rev. Lett. 9 (2005) 202502 0 -B -2 [MeV] H H H 5 He 0-2 - 5 H - -6 Nagara -6 -B -8 6 He -8 [MeV]
6 Li (K -,K + ) 6 H 6 H = [ t---n ] [ t---n ] Alpha formation Coherent - coupling [ α-ξ - -n ] Large Ξ - mixing Nemura s mechanisn Missing-mass spectroscopy in S=-2 sector via one-step process!
Concluding remarks 5 The overbinding problem of He has been virtually solved. NN force Repulsive/attractive : D0 picture Attractive : D2 picture consistency A necessary condition for YN interaction to study A. Effective N interaction Coherent - coupling is essential dynamics. + + He(0 ) - He(0 coh (- 0 mixing) in dense neutron matter ) Neutron-rich hypernuclei can provide additional evidences for coherent - coupling. 6 Li ( π,k + ) 6 H H.I. 7 H, 8 H,, 5 H, 7 H, etc.
Excitation energy (MeV) 500 00 00 200 100 A 1 Ξ 0 [ Z ] - 1 Ξ A [ Z + 1] A 2 [ Z ] + A 1 [ Z 1] A 1 0 [ Z ] - 1 A [ Z + 1] A 1 [ Z ] Issue @J-PARC Coherent - mixing in neutron-rich medium. π - A [ Z + 1] ( K -,K + ) - + - + (K, π ),( π,k ) ( K -, π ),( π +,K + ) 0 S=-2 S=-1 A [ Z ] A A [ Z + 1] [ Z + 2 ] S=0 nuclei
Thank you very much!