Strangeness nuclear physics

at J-PARC

Tohoku University

H. Tamura

KEK-HN-2017

2017. 1. 10

Contents

1. Introduction

2. S = -1 systems

--- Charge symmetry breaking in LN interaction

3. S = -2 systems --- X-nuclear bound states

4. Kbar-nucleus system

5. Future prospects

6. Summary

1. Introduction

Quarks/gluons

Nuclei

Hadrons

Hadron

structure

Baryon-baryon

interactions

nuclear

matter

QGP

color s.c.

quark matter

hadronic

matter

How are hadrons formed

from quarks and gluons?

How are nuclei formed

from hadrons?

Role of Strangeness in Hadron/Nuclear Physics

s quarks play unique roles

Constituent quarks,

other quasi particles

Test lattice QCD calculations

s, c, b quarks play important roles

Short-range force

by quark picture Meson exchange

picture

New DOF in nuclear matter

SU(3)f sym. in hadron level

(constituent quark level)

BB interactions and high density matter

ρ

S-N repul. (US= +30 MeV)

X-N attr. (UX = -15 MeV) Ba

ryo

n

fra

cti

on

C. Ishizuka et al.,

J.Phys. G35 (2008) 085201

n

p

L

X

Strange hadronic matter?

LN: Same in pure neutron matter?

LN-SN mixing?

SN: How repulsive?

XN: Attractive or repulsive?

LL: How weakly attractive?

Unbound H dibaryon exists?

KbarN: How strongly attractive in nuclear matter?

YNN, YYN repulsive? Can solve the hyperon puzzle?

Attractive LN interaction (UL= -30 MeV)

=> at least L should appear at 2-2.5r0

S-N repul. (US= +30 MeV)

X-N attr. (UX = -15 MeV) We need YN, YY int.

both in free space

and in nuclear matter

◆ n-rich L hypernuclei

6LH not observed, 9LHe

◆ g spectroscopy of L hypernuclei 4

LHe g-ray for CSB 4LH g-ray, 7LLi B(M1), …

◆ YN scattering

S±p scattering exp

◆ Weak decay of L hypernuclei

◆ L hypernuclear spectroscopy via (e,e’K+) 7

LHe, 10LBe, 12

LB high res. spectra 40LCa, 48

LCa

◆ Decay pion spectroscopy of L hypernuclei 4

LH mass from 4LH -> 4He + p-

◆ Lifetime of light L hypernuclei via HI beams Short 3LH lifetime

E10

E15

ρ

E27

◆ (Partly) took data

◆ running

◆ Under preparation

◆◆ Emulsion experiments X - 14N bound state More LL hypenuclei

◆ X hypernuclear spectroscopy 12

X Be observed

◆ X atom X rays

◆ H dibaryon search

E05

E03

E13

Present status of strangeness experiments

KEK

◆ K-pp search K-pp spec. via 3He(K-,n) K-pp like bump via d(p+,K+) Not obderved at

◆ L(1405) study via d(K-,n)

◆ K-d, K-He atom X rays

Jlab

J-PARC

MAMI

GSI-HypHI, STAR, ALICE

Kbar-nuclear systems

S=-1 systems: more accuracy S=-2 systems: more events

E63

E40 E07

E07

E42

KEK E373

E62 E57

E22 E18

E31

LEPS, GSI

2. Single Strangeness

Charge Symmetry Breaking

in L hypernuclei

(K-,p- )

Charge Symmetry Breaking (CSB)

in A=4 hypernuclei

Old emulsion data

Old NaI data

4LH

4LHe

? 1.09±0.02

1.15±0.04

0 3He + L 3H + L

M. Juric et al. NPB 52 (1973) 1

Bedjidian et al.

PLB 62 (1976) 467

PLB 83 (1979) 252

no systematic error

Measure with Ge

p

n

L

CSB in NN force (pp ≠ nn)

=> B(3H) - B(3He) – EM effect ~70 keV

CSB in LN force (Lp ≠ Ln)

BL(4LH) - BL (

4LHe) = -350 keV

Measure using weak decay

pion

YN interactions models

BL(4LH) - BL (

4LHe) = 0-70 keV

Experimental confirmation

awaited

Decay-pion spectrum at MAMI

Emulsion data in

binding energy scale

decays of quasi-free

produced hyperon accidental background A. Esser et al., PRL 114 (2015) 12501

4LH -> 4He + p-

Hypernuclear g-ray data (2014)

Hyperball:1998~

Hyperball2: 2004~

6.050 1-

2- 3/2-

M1

PTEP (2015) 081D01

LN spin-dependent interaction strengths determined:

D = 0.33 (A>10), 0.42 (A<10), SL = -0.01, SN = -0.4, T =0.03 MeV

• Almost all these p-shell levels are reproduced

by this parameter set. (D.J. Millener)

• Feedback to BB interaction models. Nijmegen ESC08 model is

almost OK. (But LN-SN force is not well studied yet.)

=> go to s-shell and sd-shell

1,.09

Old NaI data

K－

＊Z),(Z AA

L

-- pK

Detect g-rays from hypernuclei

Tag production of hypernuclei

K1.8 Beamline

Spectrormeter

g spectroscopy setup

g LZA p-

Various

PID counters

(2.5 T)

SksMinus: wide and large

acceptance

1.2 ~ 2.0 GeV/c, 0 ~ 20 deg.,

> 80msr

Pion

spectrometer

“SksMinus”

4LHe : liq.He target

(2.5 g/cm2)

pK = 1.5 GeV/c 19

LF : liq. CF4 target (20

g/cm2)

pK = 1.8 GeV/c

Ge array “Hyperball-J”

J-PARC E13

H. Tamura et al.

K－

＊Z),(Z AA

L

-- pK

Detect g-rays from hypernuclei

Tag production of hypernuclei

K1.8 Beamline

Spectrormeter

g spectroscopy setup

g LZA p-

Various

PID counters

(2.5 T)

SksMinus: wide and large

acceptance

1.2 ~ 2.0 GeV/c, 0 ~ 20 deg.,

> 80msr

Pion

spectrometer

“SksMinus”

4LHe : liq.He target

(2.5 g/cm2)

pK = 1.5 GeV/c 19

LF : liq. CF4 target (20

g/cm2)

pK = 1.8 GeV/c

Ge array “Hyperball-J”

J-PARC E13

H. Tamura et al.

Ge cooled down to ~70K

(c.f. 92K w/LN2) to reduce

radiation damage

+ fast PWO counters

Eff. = 5.4% @1 MeV

with 28 Ge(re=60%)

Hyperball-J

DE= 3.1(1) keV at 1.33 MeV

Pulse-tube

refrigerator

T. Koike et al., Nucl. Instr. Meth. A 770 (2015) 1

4L He g-ray spectrum

Present data

Doppler shift correction

95±13 counts

K-

p-

4LHe

b

A peak observed at 1406±2±2 keV

Missing mass of 4He(K-,p-)

pK = 1.5 GeV/c

Fit with

simulated

Doppler-corrected

peak shape

4LHe

DBL(1+) : 0.03±0.05 MeV

DBL(0+) : 0.35±0.05 MeV (0.26±0.09 MeV)

T.O. Yamamoto et al.,

PRL 115 (2015) 222501

Existence of a large CSB effect confirmed only by g-ray data

BL [ 4

LH(0+) ] confirmed, suggesting the emulsion 4LHe(0+) data also reliable

Large spin dependence in CSB found by combining all the data

4LH g-ray will be precisely measured in E63

Results A. Esser et al.,

PRL 114 (2015) 12501

＊Exact calc. including SS- mass difference as well as CSB in BB force

(Nijmegen SC97e) gives only DBL(0+) ~70 keV.

What is the origin of the large CSB effect?

＊p-shell hypernuclear levels are very well reproduced by L-S coupling

from “D2” interaction. Millener (2005)

D2: central only LS coupling

SC: tensor dominated LS coupling

＊Shell model calc. using D2 gives DBL(0+) ~200 keV.

A. Gal, PLB 744 (2015) 352

D2: Akaishi et al., PRL 84 (2000) 3539

Nogga et al., PRL 88 (2002) 172501

＊Ab initio calc. using Bonn-Juelich EFT force (LO) reproduces

D(BL(0+)- DBL(1+)) ~0.3 MeV.

D. Gazda and A. Gal, PRL 116 (2016) 122501

LN-SN coupling

force

= central dominated LS coupling

The observed CSB effect is sensitive to

the LN-SN coupling force.

L

L

S0

p

N

N

LS

coupling

CSB

u/d quark mass difference + EM effects => CSB in hadrons and h-h int.

2. Double strangeness

( X-nuclear systems)

“Kiso event” found by overall scanning method

>

>

8Li

p

e-

a

a

8Be

p

d

:

The first evidence for a deeply bound X state -> X--nucleus is attractive

K. Nakazawa et al.PTEP 2015, 033D02

- = -

KEK E373

K. Nakazawa et al.

Measure tracks

by counters

More S=-2 events with emulsion

p-

L→ Np, LN→NN

Fragmentation

X production

X absorption

Weak decays

p

10 times more samples of LL hypernuclei and X-nuclear bound states

Confirm LL interaction strength, LL – XN interaction

X-nuclear potential -> X-N interaction

Measure X- -atomic X-rays with Ge detectors

Shift and width of X-rays -> X-nuclear potential at the nuclear surface

Running in 2015 and 2016

J-PARC E07

K. Nakazawa et al.

Emulsion plate

X-atomic X-rays via “Hyperball-X” (Ge array)

beam

emulsion

12C target for X production

SSD

10

cm

Clover Ge (4 segments)

BGO counters for background suppression

Energy (keV)

0 100 200 300 400 500 600 700 800

Coun

ts/2 k

eV

0

10

20

30

40

50

60

simulation

316 keV

370 keV 511 keV (from π0)

Select X absorption events with emulsion

-> almost no background in X-ray spectrum

Expected shifts: 0.3– 3 keV

Hyperball-X

ephoto = 2.3% @ 350 keV

sys. error < 0.1 keV (rms)

stat. error ~ 0.1 keV (rms)

Discovery of Ξ-hypernuclei as a peak(s)

Measurement of Ξ-nucleus potential depth and width

Coupling between Ξ-nucleus and ΛΛ-nucleus

Spectroscopic Study of Ξ-Hypernucleus, 12ΞBe,

via the 12C(K-,K+) Reaction

D1, 86t, 1.5 T

Q1, 37t, 8.7 T/m

Q2, 12t, 5 T/m

S-2S Spectrometer

∆E=1.5 MeV(FWHM)

J-PARC E05 Nagae et al.

Magnets are ready

Results of the pilot run (2015)

K-p→K+Ξ- 6000 Ξ-/day at J-PARC !!

(CH2)

12C(K-, K+)

QFΞ

Using the existing SKS spectrometer (110 msr)

p(K-,K+) and 12C(K-,K+)

p(K-,K+)X-

Slide by Nagae/Kanatsuki

ΔE～5.4 MeV fwhm

Slide by Kanatsuki

=> Suggesting

a rather deep

X-nuclear potential

4. Kbar –nuclear systems

(K-pp search at J-PARC)

=> Dote’s talk

K-pp search via d (p+,K+) L*p

reaction

J-PARC E27

T. Nagae et al.

Y. Ichikawa et al., PTEP (2014) 101D03

1.69 GeV/c

Mass shift

~30 MeV

ΣN-ΛN Cusp

@2.13 GeV

K-pp ?

Y. Ichikawa et al., PTEP (2015) 021D01

S0p mode

Two energetic protons in Seg2 or 5

The bump in the ratio spectrum is well explained The ratio of

One proton coincidence Inclusive

Proton coincidence spectrum

BE(K-pp) =

G =

KbarNN search via 3He(K-,n)

27

J-PARC E15

M. Iwasaki et al.

The latest result: 3He(K-,Lp)n

28

E152nd

M[K

+p+p

]

E151st

Y. Sada, et al,

Prog. Theor. Exp. Phys. (2016) 051D01

performed in 2013 performed in 2015 - with x30 more data

Slide by Yamaga

4. Future Plans

Charm/ S=-3 systems

“Hypernuclear Microscope”

Abundant S=-1 systems “Hyperon Factory”

2nd production target

3rd

production

target

Precise S=-1 systems

< 1.1 GeV/c

< 2.0 GeV/c

Dp/p ~ 10000

<10 GeV/c

Separated beam

muon for m-e

conversion

5 deg extraction

~5.2 GeV/c K0

J-PARC Hadron Hall

Extension Plan

30 GeV p

<31 GeV/c unseparated beam

S=-2 systems < 2.0 GeV/c

S=-1 systems < 1.1 GeV/c

Charm/ S=-3 systems

“Hypernuclear Microscope”

Abundant S=-1 systems “Hyperon Factory”

2nd production target

3rd

production

target

Precise S=-1 systems

< 1.1 GeV/c

< 2.0 GeV/c

Dp/p ~ 10000

<10 GeV/c

Separated beam

muon for m-e

conversion

5 deg extraction

~5.2 GeV/c K0

J-PARC Hadron Hall

Extension Plan

30 GeV p

<31 GeV/c unseparated beam

S=-2 systems < 2.0 GeV/c

S=-1 systems < 1.1 GeV/c

We have almost no information on BB forces in high density (r > r0) matter

Density dependence of LN interaction in matter

Ab-initio calc. of nuclear binding energies => NNN repulsion necessary

Similar YNN (YYN, YYY) repulsive forces?

Experimentally approach:

Precise BL data for wide A of L hypernuclei

0.1 MeV accuracy is necessary

MPa

sL

pL

dL fL gL

-BL

[

MeV

]

ESC08 only (no 3B force)

+ 3B/4B repulsion in NNN only

+ 3B/4B repulsion in NNN +YNN etc.

Yamamoto, Furumoto, Rijken et al. PRC88 (2013) 2, 022801 PRC90 (2014) 045805

(Mpa)

ECS08 only

Electrostatic Separator

Prod. T High Res. Spectrometer

Exp. Target

Mass Slit

Achromatic Focus

High-Intensity High-Resolution line (HIHR)

Intensity: ~ 1.8x108 pion/pulse

(1.2 GeV/c, 50 m, 1.4msr*%,

100kW, 6s spill, Pt 60mm)

Dp/p ~ 1/10000 (Dm~200 keV)

Designed by Noumi

BE accuracy < 0.1 MeV => Density dependence of LN interaction

Recent Highlights in Strangeness NP experiments at J-PARC

More accuracy in S=-1 Large CSB effect in A=4 found.

4

LHe g-ray measurement

More events in S=-2 X-nucleus bound systems observed.

X-14N bound system observed in emulsion (Kiso event). A pilot run spectrum for 12C(K-,K+) 12

XBe shows bound state events.

K-pp systems New positive data appeared.

A broad peak in (p-,K) reaction may be interpreted as a deep K-pp state. High statistic data in (K-,n) imply a shallower bound state.

New experiments at J-PARC + Hadron Hall extension plan => YN interaction in nuclear matter => hyperon puzzle

Summary