Experimental Study of the Kaonic Bond State

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1 2008 / 06 / 06~10 Experimental Study of the Kaonic Bond State M. Iwasaki Advanced Meson Science Lab. MESON CRACOW

2 Purpose in perspective manner - to detect quark degree of freedom similar to other meson studies... nature of confinement... - chiral symmetry breaking and its restoration origin of hadron mass... - kaon condensation? - high density object? neutron star...?... long way to go...

3 200 MeV - Study of KN interaction 1.5 Scattering K + K - 1 : ~100 level shift and absorption width 0.0 Γ/100 MeV T. Waas, N. Kaiser & W. Weise, Phys. Lett. B379 (1996) : < 1 ~ level energy and decay width strongly attractive in I=0 channel

4 - KN study by atomic states kaonic hydrogen energy level [kev] W = 0 MeV W = 10 MeV W = 0 MeV W = 20 MeV W = 10 MeV level shift and absorption width Kaonic hydrogen puzzle Beer et al DEAR shift (-!E 1s ) [ev] Iwasaki et al KpX " # $ % # $ % " KpX (KEK) & DEAR (DAFNE) potential real part (V) [MeV] what is the nature of Λ(1405)? SIDDHARTA (DAFNE)... Widmann E17 (J-PARC)... Hayano

5 - KN study by atomic states level shift and absorption width Calculated 2p level shift by Akaishi repulsive side (Coupled Channel) Y.Akaishi:EXA05 20 shift [ev] 10 0 K He 2p atomic level shift experimentally allowed region K He 2p atomic level shift first ~ ev precision experiment E570 (KEK) Ti fluorescence Ni fluorescence... Tatsuno Kaonic helium x-ray spectrum -10 attractive side theoretically favored region smaller shift is also possible...

6 - KN study by atomic states level shift and absorption width E17: K - 3 He 3d - 2p x-ray K at rest application of well proven experimental method in KEK PS-E570 In-flight reactions T0 K - x-rays charged particles by K - reaction trace back by CDC E17 (J-PARC)... Hayano

7 - KN study by atomic states isospin dependence of KN SIDDHARTA (DAFNE)... Widmann kaonic hydrogen run (with improved shielding) is possible with an integrated luminosity of 400 pb -1 shift ~ ± 10 ev width ~ ± 35 ev SIDDHARTA DAFNE K - p & K - d 2p - 1s a first kaonic deuterium experiment needs improvement - has to be achieved during the kaonic hydrogen run

8 - KN study by nuclear states Does it exist?... need more study Λ(1405) as a K - p bound state resolved kaonic hydrogen puzzle Deep! KEK-PS E228 (KpX) ~ 100 MeV cf: B Ν ~ 10 MeV A. Dote et al. : PLB 590 (2004) 51 Narrow! ~ 20 MeV = meta-stable Shrink! = high density! hadron mass astronomical study Y. Akaishi & T. Yamazaki : PRC 65 (2002)

9 KN study by nuclear states KEK PS-E549: 4 He(stopped K -, N) 4 He(stopped K-, np) spectroscopy spectrum 4 He K - E549 (KEK)... Sato p p n K - n Z : +1, T : 0 or 1 p n n K - p Z : 0, T : 1 4X10 4 4X He(K -, p) inclusive energy loss corrected 4 He(K -, nx ) semi-inclusive counts [per 5 MeV/c] 3X10 4 2X10 4 counts [per 10 MeV/c] 3X10 4 2X10 4 1X10 4 1X proton momentum [MeV/c] neutron momentum [MeV/c]

10 KN study by nuclear states KEK PS-E549: 4 He(stopped K -, N) E549 (KEK)... Sato proton yield [ /stopped K - / 2.5 MeV/c 2 ] (x10-2 ) (x10-3 ) "NN close up #NN "$NN missing mass [MeV/c 2 ] #$NN 3200 upper limit [ /stopped K - ] ! = 0 MeV! = 20 MeV! = 40 MeV deep & narrow excluded. (BE>100MeV) (Γ<20MeV) 3150 missing mass [MeV/c 2 ] 3200 wide, if exist (more difficult)

11 E549/E570 (KEK)... Suzuki ΛN invariant mass vs ΛN total momentum Λp Λn YN+2N πyn+2n ~ 0.3%/K at rest ~ 3%/K at rest 1. NN I=0,S=1 dominance of K - NN I,S -> ΛΝ severe background 2N abs. 2. More intense contribution of B p/n for kaon at rest kinematics

12 FINUDA experiment invariant mass of back-to-back Λp pair from kaon absorption at rest RUN-I ( ) PRL 94, (2005) RUN-II ( ) ( 6 Li+ 7 Li+ 12 C) target dependence effect of FSI (pointed by Magas et al.) preliminary K - pp? The correlation between another YN pairs (Λn, Σ - p) has been also investigated.

13 OBELIX experiment (pbar annihilation on 4 He at rest) Λp (ppπ - ) Λd (pπ - d) not highly consistent though

14 New data from Osaka group (one of new data : in-flight) indicating very deep potential Kaon condensation? in-flight (K-, n) 1 GeV/c T. Kishimoto et al., Prog. Theor. Phys. 118 (2007) 181 fit = Green s function - deep & wide KN pot. Re(V) ~ 200 MeV Im(V) ~ 50 MeV - lower background in-flight ensures... 2N process suppressed kinematically separated not seen in the spectra

15 - KN study by nuclear states level energy and decay width!" E15: 3 He(K -, n) missing & invariant mass U nucl K MeV 0-50 #" -200 #(1405) E K = -27 MeV $ = 40 MeV K U nucl K MeV r fm 0-50!" #" -200 U nucl K MeV r fm 0-50!" #" -200 r fm 3 KH E K = -108 MeV $ = 20 MeV K K - pp simplest system less excited states less ambiguity full kinematical reconstruction minimum absorption multi-nucleon absorption Data from FINUDA group M. Agnello et al. Phys. Rev. Lett. 94 (2005) K + p K + pp K + ppn T. Yamazaki, Y. Akaishi / Physics Letters B 535 (2002) 70

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17 p(p, K + ) pp -> pp K - + K + COSY GSI missing mass invariant mass FOPI simulation (from proposal)

18 Theoretical progress 3 He(K -, n) K - 3 He -> pp K - + n d 2! / d" n de n (µb/(sr MeV)) bound state will be seen - yield 5 ~ 40 µb / (sr MeV) - resolution must < 20MeV bound region unbound region K - Conversion 1-body absorption 2-body absorption deep pot. d 2! / d" n de n (µb/(sr MeV)) He (K -, n) K - pp conversion part s state p state d state Chiral unitary shallow pot T n (MeV) T. Koike, T. Harada, Phys. Lett. B652 (2007) T n (MeV) J. Yamagata, S. Hirenzaki, H. Nagahiro, D. Jido, Mod. Phys. Lett. A accepted. Proc. of Chiral07.

19 mesonic decay mode shallow pot. case I=0 dominance + by π π - tag

20 Theoretical progress Chiral unitary shallow pot. J. Yamagata-Sekihara, H. Nagahiro, D. Jido, S. Hirenzaki, in preparation Chiral unitary 3 He (K -, n) K - pp + by π π - tag d 2! / d" n de n (µb/(sr MeV)). 8 4 conversion part s state p state d state shallow pot T n (MeV) J. Yamagata, S. Hirenzaki, H. Nagahiro, D. Jido, Mod. Phys. Lett. A accepted. Proc. of Chiral07.

21 3 He(K -, n) K - 3 He -> pp K - + n J-PARC 1 GeV/c missing & invariant mass K1.8BR K - 3 He K - pp π Λ

22 ... atomic states Summary DAFNE SIDDARTA: K - p & K - d 2p - 1s J-PARC E17: K - 3 He 3d - 2p... nuclear states (not clear so far) COSY ANKE: p(p, K + ) missing mass GSI FOPI: p(p, K + ) invariant mass J-PARC E15: 3 He(K -, n) missing & invariant mass DAFNE AMADEUS: 3 He(stopped K -, N) LEPS? more..? situation will be clarified soon

23 Thank you!