Strangeness Nuclear Physics

Transcription

1 QUCS12 December 14, 2012 Strangeness Nuclear Physics Present status and future prospect at J-PARC Dept. of Physics, Tohoku University H. Tamura

2 Contents 1. Introduction 2. hypernuclei 2.1 (p,k + ) spectroscopy and n-rich hypernuclei 2.2 g spectroscopy of hypernuclei 3. S-nuclear systems 4. Double strange systems 5. Future plans at J-PARC 6. Summary

3 1. Introduction

4 Strangeness World of matter made of u, d, s quarks Nu ~ Nd ~ Ns Stable Strangeness in neutron stars ( r > 3-4 r 0 ) Strange hadronic matter (A ) Higher density, X Hypernuclei Z -2-1, S Hypernuclei N 0 3-dimensional nuclear chart by M. Kaneta inspired by HYP06 conference poster

5 hypernuclear chart Better resolution (2012) Neutron-richer hypernuclei > 1 MeV (FWHM) > 2 kev (FWHM) > 0.4 MeV (FWHM) 6 H Updated from : O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564. KEK, DAFNE (K - stop, p + )

6 Motivations of strangeness nuclear physics Extension of 3D nuclear chart BB interactions Unified understanding of BB forces by u,d ->u, d, s particularly short-range forces by quark pictures Test lattice QCD calculations Impurity effect in nuclear structure Changes of size, deformation, clustering, collective motions, appearing new symmetry, Clues to understand hadrons and nuclei from quarks Modifications of baryon properties in nuclei m in a nucleus, evels of heavy hypernuclei,... Cold and dense nuclear matter with strangeness m

7 Nuclear matter in neutron stars The heavy n-star Baryon (M=1.97 fraction ± 0.04 M ) can be supported? Cooling speed can be U explained? S > 0, U X < 0 Hyperons really appear? S s appear? X s appear? K bar s appear? Quark matter exists?? Strange hadronic matter n p X? Neurtron matter n Baryon fraction U S < 0, U X < 0 We still need XN, SN,, K bar N forces, N odd-state force, NNN and YNN force, Quark matter?? A new form of matter actually existing in the universe

8 Overview of Strangeness Nuclear Physics Experiments K - or p +/- beams KEK-PS, BN-AGS => J-PARC and S hypernuclear spectroscopy, g-spectroscopy of hypernuclei and X hypernuclei, SN /N scattering weak decays of hypernuclei K - nuclei, K - atoms e - beam Jefferson ab (Hall A, Hall C), Intensity increasing. SNP programs just being started. MAMI-C high-res. hypernuclear spectroscopy, weak decays of hypernuclei K - from f DAFNE (FINUDA, SIDDHARTA, AMADEUS) spectroscopy of hypernuclei, weak decays of hypernuclei K - nuclei, K - atoms Heavy ion beams GSI (HypHI) p-rich/n-rich hypernuclei, lifetimes, multi-strange nuclei

9 2. hypernuclei 2.1 (p, K + ) spectroscopy and n-rich hypernuclei

10 Previous (p +,K + ) data and N interaction SKS at KEK-PS p + n -> K + -> Established U = - 30 MeV (c.f. U N = -50 MeV) Better resolution p-rich/n-rich hypernuclei Mass of hypernucleus -B (MeV) Hotchi et al., PRC 64 (2001) (e,e K + ) at Jlab, (p -,K + ) reaction, g spectroscopy

11 Neutron-rich hypernuclei 10 B (p -, K + ) 10 i 11.1±1.9 nb/sr p p ~1.2 GeV/c p - p p -> n K + 2-step charge exchange (p - p->p 0 n, p 0 p->k + etc.) Via S - admixture in hyp. (p - p->s - K +, S - p<->n) -S coherent coupling -> NN attraction Almost no background Akaishi et al., PR 84 (2000) 3539 KEK E521, SKS PR 94 (2005) First data on n-rich hypernucleus New data from FINUDA@DAFNE 6 H events by 6 i(k - stop,p + ) PR 108 (2012) p n important in neutron stars?

12 How to extend S=-1 nuclear chart? target nuclei 14 B 15 B 17 B 19 B High-resolution (DE~200 kev(fwhm)) study with HIHR beam line single charge Exchange (Jlab) (e,e K + ) 14 Be (K -, p - ) (p +,K + ) (p -,K + ) J-PARC E10 (Sakaguchi et al.) double charge exchange (J-PARC) 8 B 15 B 16 B 17 B 18 B 19 B 20 B 21 B 22 B 6 Be 14 Be 15 Be 16 Be 17 Be 5 i 13 i 14 i 5 H 8 H 10 He 11 He Heavy ion collision in the only method (@GSI/FAIR)

13 2.2 g spectroscopy

14 Hypernuclear g-ray data (2012) 3/ New! M1 NPA835 (2010) 422

15 Well known from U = - 30 MeV N spin-dependent interactions Two-body N effective interaction Dalitz and Millener s Gal, Ann. Phys. approach 116 (1978) V Millener et al., Phys. Rev. C31 (1985) 499 D S S N T p-shell: 5 radial integrals for s p N w.f. D = V (r) u (r) 2 r 2 dr, r = r - r s g-ray data => D = 0.33 (0.43 for A=7), S = -0.01, S N = -0.4, T= 0.03 [MeV] Small spin-dependent forces have been established. s p N Feedback to BB interaction models thru G-matrix calc. (Millener) Nijmegen models D S S N T (MeV) ND NF NSC NSC97f ESC04a ESC08a ( Quark model ) Exp S force: All Nijmegen models fail. Quark model looks OK.

16 g-factor of in a nucleus Changes by partial restoration of chiral symmetry? e h m q = m q : Const. quark mass 2m q c m Reduction of m q in nuclear matter -> enhancement of m?? -spin-flip M1 transition B(M1) J c J c +1/2 core nucleus M1 J c -1/2 in s-orbit g g c in s-orbit hypernucleus Õ ª Õ c "hypernuclea fine structur Õ «Õ c ~100% Doppler Shift Attenuation Method Core polarization (change of g c by ) should be small. Prelim. data for 7 i(3/2 + ->1/2 + ) (BN E930, M.Ukai) g = m N g (free) = m N J-PARC E13 (Tamura et al.) g spectroscopy of light hypernuclei D g -g c ~ 3% for 7 i, ~10% for 19 F

17 How weak are the -spin-dependent forces? Tamura et al., PR 84 (2000) 5963 D = 0.42 MeV => N spin-spin force ~ 1/10 of NN spin-isospin force Ajimura et al., PR 86 (2001) 4255 (S = MeV) => N spin-orbit force ~ 1/40 of NN spin-orbit force But the core polarization effect should be theoretically estimated. + Meson exchange effect + S- mixing effects should be estimated.

18 3. S-nuclear systems

19 What we know about S-N force arge spin-isospin dependence in SN force 4 S He suggests (I,S) = (3/2,0), (1/2,1) attractive (3/2,1), (1/2,0) repulsive -- Consistent with meson exchange models S Si Nuclear potential (KEK E438) 28 Si (p -,K + ) at 1.2GeV Strong repulsion comes from Pauli effect between quarks? Quark Cluster Model attice QCD V 0 ~ -10 MeV W 0 ~ -10 MeV PR 87(2002) > Strongly repulsive potential (U~ +30 MeV) How repulsive are (I,S) = (3/2,1), (1/2,0) channels? SN (I,S) = (3/2,1) S s never appear in n-stars? High statistics S + p/ S - p scattering experiment planned at J-PARC

20 Baryon Baryon interaction by attice QCD (27) The same behavior was predicted by Oka-Yazaki s Quark Cluster Model Slide by Koji Miwa 6 independent forces in flavor SU(3) symmetry 8 〇 x 8 = Strong repulsive core J-PARC E40 S + p (S=1, T=3/2) S - p (S=0, T=1/2) (10*) (10) (8s) (8a) (1) quark Pauli effect X - p (T=0) Flavor singlet (H-Channel) J-PARC E42 color magnetic interaction attice QCD, T. Inoue et al. Prog. Theor. Phys. 124 (2010) 4 Weakly repulsive or attractive Core

21 J-PAR E40 (Miwa et al.) Sp Scattering Experiment Hyperon production 1.3 GeV/c p +- p -> K + S +- reaction S +- track not directly measured Measure proton momentum vector -> kinematically complete JPARC K1.8 beam line + SKS p p S Fiber tracker p H2 target MPPC+Sci.fiber Calorimeter K + p/n Forward calorimeter PiID counter => ds/dw for S + p, S - p, S - p->n (p S = MeV/c) Phase shift of 3 S 1 channel

22 4. Double strange nuclear systems

23 hypernuclei via emulsion+counter hybrid method (KEK E373) Nagara event #8 6 He (unique and accurate) DB = 0.67±0.17 MeV Mikage event 6 He Nakazawa (Hyp-X conf.) DB = 3.82 ±1.72 MeV Demachi-yanagi event 10 Be* (w/ theoretical help) Hida event 11 Be DB = ± cf. Ex = 3.0 DB = 2.27 ±1.23 MeV

24 J-PARC E07 (Nakazawa, Imai, Tamura et al.) S=-2 Systems with Emulsion-Counter Hybrid Method Nagara event PR 87 (2001) p n DB = MeV Big impact on neutron star Ten times more events (~10 2 ) of hypernuclei Remove nuclear dependence and details of force - correlation (H dibaryon-like state) in nucleus from -> S - p decay Measure X - -atomic X-rays with Hyperball-J Shift and width of X-rays -> X-nuclear potential Stopped X - events identified from emulsion Measure tracks by counters

25 ] [counts/ 0.5MeV J-PARC E05 (Nagae et al.) K - p -> X - K + X-hypernuclear spectroscopy by (K -,K + ) First spectroscopic study of S=-2 systems in (K -,K + ) reaction Properties of XN Interaction Attractive or repulsive? How large? X appears in neutron stars? Isospin dependence? <- Different targets XN- coupling force? <- Xp conversion width <- X and hypernuclear mixing states Expected 12 C (K -,K + ) 12 XBe Spectrum First spectroscopic study of S=-2 V systems in (K -,K + ) X = -20MeV reaction V X = -14MeV First step to multi-strangeness baryon systems s X p X -> Take a similar spectrum for (K -,K + ) reaction -B X [MeV] 4 weeks w/ full beam E meas. = 3 MeV FWHM

26 5. Future Plans at J-PARC

27 K1.1BR COMET K High-p 2 nd production target K1.8BR Hadron Hall Extension Plan K - nucleus bound states K - atomic X rays K1.8 S=-2 systems X hypernuclei hypernuclei X-atomic X rays K1.1 g spectroscopy of hyp. weak decays of hyp. S=-1 systems SN, N scattering Extension Plan of J-PARC Hadron Hall K10 Charm S=-3 systems 3rd production target X *, W *, W hypernuclei KK-nucleus D, h c, c in nuclei HR K Precise S=-1 systems high resolution hyp. n-rich hyp. magnetic moment

28 6. Summary Strangeness nuclear physics studies BB forces, impurity effects, inmedium baryon properties and provides clues for neutron star matter. hypernuclear spectroscopy: Neutron-rich 10 i and 6 H observed. Will investigate NN force in n-rich environment. g-spectroscopy of hypernuclei: From p-shell data, spin-dependent N int. strengths determined. In-medium g to be measured from B(M1). S-nuclear systems: strongly repulsive potential observed. S-p scattering experiment planned to confirm the quark Pauli effect. Double strange systems: 6 He revealed force weakly attractive. X hypernuclei to be first studied to measure the XN force. Extension of J-PARC Hadron Hall will extend strangeness nuclear physics further. Collaborations with theoretical studies of lattice BB forces, nuclear structure, etc. are more and more important.

29 新学術領域 実験と観測で解き明かす中性子星の核物質 Grant-in-aid for innovative area: Nuclear Matter in neutron Stars investigated by experiments and astronomical observations Project leader: H. Tamura Theory group: A. Ohnishi