Dense K nuclei - To go forward -

1. A. Dote （KEK） ´ Dense K nuclei- To go forward - • Introduction • Exotic properties of K nuclei • To go forward (Future plan) • Summary Y. Akaishi (Nihon univ.) T. Yamazaki (RIKEN) W. Weise (TU Muenchen) KEK Nuclear workshop @ KEK, ’06.Aug.3

2. K nuclear state K nuclear state Introduction What are kaonic nuclei (K nuclei)? • K- meson is bound in a nucleus by strong interaction. cf) Kaonic atom K- meson is around a nucleus, bound by Coulomb interaction. • K nuclei can exist as discrete states, • since K- meson is deeply bound below Σπ threshold. KNNN… ΣπNN…

3. Very attractive I=0 KN interaction makes … Deeply bound; Binding energy of K- > 100 MeV Discrete state; Below Σπ threshold ... Deeply bound kaonic nuclei Phenomenological KN potential (AY KN potential) Strongly attractive. • free KN scattering data • 1s level shift of kaonic hydrogen atom • binding energy and width of Λ(1405) = K- + proton Y. Akaishi and T. Yamazaki, PRC 52 (2002) 044005

4. My motivation … Akaishi’s special lecture held in Kyoto university in ’00. 8Be + K- Only one K- meson can drastically change the nuclear structure? Y. Akaishi and T. Yamazaki, PRC 52 (2002) 044005

5. K- Fully microscopic treatment No assumption on nuclear structure; cluster, deformation … System self-organizes only following energy variation. Kaonicnucleus normal nucleus ?? ? ? ? ?? ? What kind of structure does A+1 system favor? Exotic features of K nuclei Antisymmetrized Molecular Dynamics（AMD） K- meson = a seed of strong attraction Normal nucleus p p n n

6. Single nucleon/kaon wave function + Charge projection of total wave function ☆ Improve AMD for K nuclei mixing

7. Deep potential Y. Akaishi T. Yamazaki A. Dote W. Weise Shallow potential E. Oset H. Toki A. Gal Akaishi-san’s talk Prof. Oset’s talk Hamiltonian in AMD calculation : effective NN int. Tamagaki potential (OPEG) : effective KN int. AY KN potential G-matrix method Y. Akaishi and T. Yamazaki, PRC 52 (2002) 044005 vs

8. Isovector deformation Binding energy of K- = 104 MeV Nucleus-K-threshold pppK- (simple AMD) Σπ threshold Width (Σπ, Λπ) Density (/fm^3) 0.0 0.41 0.83 Density (/fm^3) 0.0 0.10 0.20 8BeK- Proton satellite Rrms = 1.42 fm β = 0.55 Central density = 0.76/fm^3 8Be Rrms = 2.46 fm β = 0.63 Central density = 0.10 /fm^3 4.5 normal density AMD studies revealed … • E(K) > 100 MeV for various light nuclei • Drastic change of the structure of 8Be, • isovector deformation in 8BeK- • Highly dense state is formed in K nuclei. • maximum density > 4ρ0 • averaged density 2～4ρ0 • Proton satellite in pppK- A. D., H. Horiuchi, Y. Akaishi and T. Yamazaki, PLB 590 (2004) 51; PRC 70 (2004) 044313.

9. 1.67 1.14 1.78 2.55 2.53 4 fm Single K- meson can interact with limited numbers of nucleons? Saturation of E(K) 4.1ρ0 Various shapes of K nuclei ppnK- pppK- pppnK- 3 fm 8.8ρ0 9.2ρ0 7.6ρ0 6BeK- 9BK- 4 fm 4.1ρ0 5.4ρ0

10. ①Deeply bound and Dense ②Drastic change of structure 8Be 8BeK- ③Isovector deformation ④proton satellite pppK- Kaonic nuclei ＝ exotic system

11. Various groups are trying to search for deeply bound kaonic nuclei in various way. • T. Suzuki, M.Iwasaki et al; 4He(stopped K-, n or p) @ KEK ppnK-: B.E. = 169MeV, pnnK-: B.E. = 195MeV • H. Fujioka, T. Nagae et al; ppK- @ DAΦNE ppK-: B.E. = 116MeV • Kishimoto et al; 16O(inflight K-, n) 15OK- @ BNL • N.Herrmann et al; • Invariant-mass method (heavy-ion collision) @ GSI • ppnK-: B.E. ～150MeV (preliminary) • K. Suzuki et al; proton induced reaction @ GSI • J-PARC

12. 真実 To go forward • The technique of • conventional nuclear physics • Phenomenological KN interaction Truth K nucleus has very exotic properties! • Experimental results are coming up.

13. 2, Using more theoretical KN interaction • Energy- and density-dependence • I=1 P-wave interaction • … Attractive below Σ(1385). • … Large contribution at high density? Additional attraction to deeply bound kaonic nuclei 3, Mystery of two-body absorption (KNN --> YN) … large decay width at high density K nuclei can survive? Collaborating with W. Weise To go forward … 1, Short-range repulsive core part of NN interaction The repulsive core part of the effective NN potential derived by G-matrix method is too much smoothed out for the study of kaonic nuclei? “Beyond the conventional nuclear physics” This part is undergoing…

14. Summary • Kaonic nuclei have interesting properties! The AMD study with AY KN interaction showed … • K- is deeply bound by ～100 MeV • and forms highly dense state. • Strange structures appear in K nuclei. • Drastic change of 8Be structure, • Isovector deformation in 8BeK-, • Proton satellite in pppK-.

15. Future plans • Study K nuclei from the viewpoint of quarks Collaborate with Y. Kanada-En’yo and O. Morimatsu - - - Λ(1405) = qqq-qq, ppK- = 7qq, ppnK- = 10qq (undeca-quarks state) • Study more various K nuclei Many experiments will start, or started. • T. Suzuki, Iwasaki et al; 4He(stopped K-, n or p) @ KEK • Fujioka, Nagae et al; ppK- @ DAΦNE • Kishimoto et al; 16O(inflight K-, n) 15OK- @BNL • Herrmann et al; Invariant-mass method (heavy-ion collision) @ GSI • K. Suzuki et al; proton induced reaction @ GSI • J-PARC • Other type of KN interaction? I=1 p-wave KN interaction… suggested by S. Wycech et al. nucl-th/0501019 Collaborate with W. Weise • Apply our wave function to the study of reaction Dense or not?(S. Hirenzaki and J. Yamagata) • Double K nuclei?

16. Λ（１４０５） KN interaction Chiral symmetry restoration Kaonic atom Kaon condensation Cold and Dense Interesting structure … Nuclear structure (Strange) Quark matter K nuclei…Exotic system ! Kaonic nucleus … related to various fields!!