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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