QUCS12

December 14, 2012

Strangeness Nuclear Physics
Present status and future prospect at J-PARC

Dept. of Physics, Tohoku University
H. Tamura

Contents
1. Introduction
2. L hypernuclei

2.1 (p,K+) spectroscopy and n-rich L hypernuclei
2.2 g spectroscopy of L hypernuclei
3. S-nuclear systems
4. Double strange systems
5. Future plans at J-PARC

6. Summary

1. Introduction

World of matter made of u, d, s quarks
Nu ~ Nd ~ Ns
Strangeness in neutron stars ( r > 3 - 4 r0 )Strangeness“Stable” Strange hadronic matter (A → ∞)Higherdensity

LL, X Hypernuclei
Z-2L, S Hypernuclei
N-10３-dimensional nuclear chartby M. Kaneta inspired by HYP06 conference posterL hypernuclear chart
Better resolution
Neutron-richer hypernuclei(2012)> 1 MeV (FWHM)> 2 keV(FWHM)> 0.4 MeV(FWHM)

6 H
L(K-stop, p+)Updated from : O. Hashimoto and H. Tamura,
Prog. Part. Nucl. Phys. 57 (2006) 564.

KEK, DAFNE

Motivations of strangeness nuclear physics
Extension of 3D nuclear chart

BB interactions
Unified understanding of BB forces by u,d ->u, d, sparticularly short-range forces by quark pictures
Test lattice QCD calculations

Impurity effectin nuclear structure
Changes of size,deformation, clustering,collective motions,appearing new symmetry,…

Clues to understandhadrons and nuclei
from quarks

Modificationsof baryon properties
mLin nuclei
mL in a nucleus,

Levels of heavy L hypernuclei,...

Cold and dense
nuclear matterwith strangenessNuclear matter in neutron stars
Baryonfraction
The heavy n-star(M=1.97± 0.04 M◎) can be supported?
Cooling speed can be
USexplained?
> 0, UX < 0 Strange
Hyperons really appear?
hadronic matter
S’s appear? X’s appear?
Lbar
K ’s appear?
np
Quark matter exists??

?

Neurtron matternX

Baryon fraction
US < 0, UX < 0Quark matter??
We still need
XN, SN, LL, KbarN forces, LN odd-state force,
NNN and YNN force, …

A new form of matter
actually existing in the universe

Overview ofStrangeness Nuclear Physics Experiments
K- or p+/- beams
Intensity increasing.
KEK-PS, BNL-AGS => J-PARC SNP programs just being started.
L and S hypernuclear spectroscopy, g-spectroscopy of L hypernuclei
LL and X hypernuclei,
SN /LN scattering
weak decays of L hypernuclei
K- nuclei, K- atoms

e- beam
Jefferson Lab (Hall A, Hall C),

MAMI-Chigh-res. L hypernuclear spectroscopy, weak decays of L hypernuclei
K- from f
DAFNE (FINUDA, SIDDHARTA, AMADEUS)
spectroscopy of L hypernuclei, weak decays of L hypernuclei
K- nuclei, K- atoms

Heavy ion beams
GSI (HypHI) p-rich/n-rich hypernuclei, lifetimes, multi-strange nuclei

2. L hypernuclei
2.1 (p, K+) spectroscopy

and n-rich L hypernuclei

Previous (p+,K+) data and LN interaction
SKS at KEK-PS
p+ n -> L K+-> Established
UL = - 30 MeV (c.f. UN = -50 MeV)
Better resolution
p-rich/n-rich hypernuclei
Mass of hypernucleus -BL (MeV)
Hotchi et al., PRC 64 (2001) 044302(e,e’K+) at Jlab, (p-,K+) reaction,g spectroscopy

p- p p -> L n K+

Neutron-rich hypernuclei
10B (p-, K+) 10 LiL

pp~1.2 GeV/c

11.1±1.9 nb/sr

2-step charge exchange(p-p->p0n, p0p->K+L etc.)
Via S- admixture in L hyp.
(p- p->S- K+, S- p<->Ln)
L-S coherent coupling-> LNN attraction

Almost nobackground
Akaishi et al.,PRL 84 (2000) 3539

important in neutron stars
KEK E521, SKS?

PRL 94 (2005) 052502

First data on n-rich hypernucleus
New data from FINUDA@DAFNE– 6LH events by 6Li(K-stop,p+) p
PRL 108 (2012) 042501

nL

How to extend S=-1 nuclear chart?
14151917B
B
B
High-resolution(DE~200BkeV(FWHM))
study with
14Be HIHR beam line

targetnuclei

J-PARC E10(Sakaguchi et al.)single charge
Exchange (Jlab)(K-, p-)(p+ ,K+)(e,e’K+)

8 B
L

double charge
exchange (J-PARC)(p- ,K+)
15B
L

16B
L

17B
L

18B
L

6Be
L

14Be 15Be 16Be 17Be
L
L
L
L

5 Li
L

13Li
L
10He 11He
L
L
5H
L

8H
L

19B
L

20B
L

21B
L

14Li
L

Heavy ion collisionin the only method(@GSI/FAIR)

22B
L

2.2 g spectroscopyHypernuclear g-ray data (2012)

1- 6.041
3/2-2-New!
M1

NPA835 (2010) 422

LN spin-dependent interactions
 Two-body LN effective interaction-VWell known
from UL = - 30 MeV

DDalitz andMillener’sGal, Ann. Phys.
116 (1978) 167
approach
Millener et al., Phys. Rev. C31 (1985) 499

SLSN

Tp-shell: 5 radial integrals for sL pN w.f.
D =∫Vs (r) |u (r)|2 r2dr, r = rsL - rpN

g-ray data => D = 0.33 (0.43 for A=7), SL = -0.01, SN = -0.4, T= 0.03 [MeV]
Small spin-dependent forces have been established.

 Feedback toBB interaction
models thru
G-matrix calc.
(Millener)
Nijmegenmodels

NDNF
NSC89
NSC97f
ESC04a
ESC08aDSLSNT-0.048
0.072
1.052
0.421
0.381
0.146

-0.131-0.175-0.173-0.149-0.108-0.074-0.264-0.266-0.292-0.238-0.236-0.241

0.018
0.033
0.036
0.055
0.013
0.055

0.0-0.01-0.4 )
-0.4

0.03

( “Quark model”
Exp.
0.4

(MeV)
LS force:
All Nijmegenmodels fail.

Quark model
looks OK.

g-factor of L in a nucleus

mL

Changes by partial restoration of chiral symmetry?
ehmq=mq : Const. quark mass
2mqc
Reduction of mq in nuclear matter -> enhancement of m??

L-spin-flip M1 transition B(M1)gL
Jc
core nucleus

gc

Jc +1/2ÕL
cª Õin s-orbit "hypernuclea
fine structurM1
Jc -1/2

L in s-orbitÕLc« Õhypernucleus“Core polarization” (change of gc by L) should be small.
~100%

Doppler Shift
Attenuation Method

Prelim. data for 7LLi(3/2+->1/2+) (BNL E930, M.Ukai)
gL = -1.1 +0.6-0.4 mNJ-PARC E13 (Tamura et al.)g spectroscopy of light L hypernuclei

gL(free) = -1.226 mN

D|gL-gc| ~ 3% for 7LLi, ~10% for 19LF

How weak are
the L-spin-dependent forces?
Tamura et al., PRL 84 (2000) 5963

D = 0.42 MeV=> LN spin-spin force~ 1/10 of
NN spin-isospin force

Ajimura et al., PRL 86 (2001) 4255

(SL = -0.01 MeV)=> LN spin-orbit force~ 1/40 of
NN spin-orbit force

But the core polarization effect should be theoretically estimated.
+ Meson exchange effect + S-L mixing effects should be estimated.

3. S-nuclear systems

What we know about S-N force
Large spin-isospin dependence in SN force
4 He suggests (I,S) = (3/2,0), (1/2,1) attractive
S(3/2,1), (1/2,0) repulsive-- Consistent with meson exchange models

 Strong repulsion comes from
Pauli effect between quarks?
Quark Cluster Model
Lattice QCD

S--28Si Nuclear potential (KEK E438)
28Si (p-,K+) at 1.2GeV

SN (I,S) = (3/2,1)
 S’s never appear in n-stars?
V0 ~ -10 MeV
W0 ~ -10 MeVHigh statistics
S+p/ S-p scattering experimentplanned at J-PARC
PRL 87(2002) 072301-> Strongly repulsive potential (U~ +30 MeV)
How repulsive are (I,S) = (3/2,1), (1/2,0) channels?

Slide by Koji Miwa

Baryon Baryon
interaction
by Lattice
QCD
The samebehavior waspredictedby Oka-Yazaki’s
Cluster Model
6 independent forcesin flavor SU(3)Quarksymmetry
x =8〇8

J-PARC E40

S+p (S=1, T=3/2)

Strong repulsive coreS-p (S=0, T=1/2)

(27)
(10*)
quark Pauli effect(10)
X-p (T=0)

(8s)

(8a)
(1)
Lattice QCD,T. Inoue et al.
Prog. Theor. Phys. 124 (2010) 4

Flavor singlet (H-Channel)

J-PARC E42color magneticinteraction

Weakly repulsive or attractiveCore

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
Fiber trackerpSp

LH2 target

MPPC+Sci.fiber

Calorimeter+Kp/n

PiID counter

Forward calorimeter=> ds/dW for S+p, S-p, S-p->Ln (pS = 400-700
MeV/c)
Phase shift of 3S1 channel

4. Double strange
nuclear systems

Nakazawa (Hyp-X conf.)
LL hypernuclei via
emulsion+counter hybrid method (KEK E373)
Nagara event

DBLL= 3.82 ±1.72 MeV

Mikage event

6

LLHe(unique andaccurate)#8

Demachi-yanagi event

6LLHe

DBLL=0.67±0.17
MeV

Hida event
1011

LLBe

LL Be*(w/ theoreticalhelp)
DBLL=-1.52 ±0.15+ 3.0cf. Ex = 3.0
DBLL= 2.27 ±1.23 MeV

J-PARC E07 (Nakazawa, Imai, Tamura et al.)
S=-2 Systems with Emulsion-Counter Hybrid Method
Nagara event
PRL 87 (2001) 212502

pLnDBLL = 0.67+- 0.17 MeV
 Big impact on neutron star Ten times more events (~102) of LL hypernuclei
 Remove nuclear dependence and details of LL force
 L-L correlation (H dibaryon-like state)in nucleus from “LL” -> 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 tracksby counters

J-PARC E05 (Nagae et al.)K- p -> X- K+

Expected 12C (K-,K+) 12XBeSpectrum

First spectroscopic study of First spectroscopic study of]

S=-2 systems in (K-,K+) reaction
 Properties of XN Interaction[counts/ 0.5MeV

X-hypernuclear spectroscopy by (K-,K+)+
S=-2X ,K )VX= systems-20MeV inp(Kreaction
V = -14MeVX

First step to multi-strangenessbaryon systemssX
How large?
X appears in neutron stars?
 Isospin dependence ?
<- Different targets
4 weeks
full beam-> Take a similarw/spectrum
 XN-LL coupling force ?
meas.= 3 MeVFWHM-,K+)Ereaction
for(K<- Xp→LL conversion width-BX [MeV]<- X and LL hypernuclear mixing states Attractive or repulsive?

5. Future Plans at J-PARC

Hadron HallExtensionPlan
X hypernuclei

K- nucleus bound states
K1.8BR K atomic X rays

K1.1BR

S=-2 systems
COMET

K1.8
KL

LL hypernuclei
X-atomic X rays

g spectroscopy of L hyp.
weak decays of L hyp.
S=-1systems SN, LN scattering

K1.1High-p
2nd production target

HRK10

3rdproduction
targetExtension Plan Charm
S=-3of J-PARCsystems
Hadron Hall
X , W , W hypernuclei*Precise
S=-1systems
high resolution L hyp.
n-rich L hyp.
magnetic moment*KK-nucleus
D, hc, Lc in nuclei

KL

6. Summary Strangeness nuclear physics studies BB forces, impurity effects, inmedium baryon properties and provides clues for neutron star matter.
 L hypernuclear spectroscopy: Neutron-rich 10LLi and 6LH observed.
Will investigate LNN force in n-rich environment.
 g-spectroscopy of L hypernuclei:
From p-shell data, spin-dependent LN int. strengths determined.
In-medium gL 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: 6LLHe revealed LL 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.

2012-2016 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 andastronomical observations”
Project leader: H. Tamura
Theory group: A. Ohnishi