Investigation of Baryon Interactions with Strangeness
( Group‐B01 )2020/1/23
T.Takahashi (KEK‐IPNS)
Contents
• Overview of Group‐B01 researches• Subjects and status of experiments at J‐PARC
• E40: p scattering• E42: Search for H‐dibaryon• E03: X‐ray spectroscopy of ‐atom
• Summary
Cluseters of strange hadrons for investigating hierarchical structure of matter (Group‐B01)
PI: H.Tamura (Tohoku U.), CI: T.Nagae (Kyoto U.), T.Takahashi (KEK), K.Miwa(Tohoku U.)
1. Origin of nuclear force NN → YN and YY
su
u udu p
p, p scattering exp.
d
u u
dss
Search for H‐dibaryon
6q d
s udd
ns
Search for n bound nucleiN int. & ‐nuclei
2. Meson‐Baryon molecule
s
uu d
u
p
K‐
(1405)=“Kp”Strucure of “Kppp” nucleus
KpKp nucleus
3. In‐medium baryon properties
Modification of g in medium
Slide by Koji Miwa
Baryon Baryon interaction by Lattice QCD
(27)
(10*)
(8s)
(10)
(8a)(1)
Lattice QCD calc.T. Inoue et al.Prog. Theor. Phys. 124 (2010) 4
Strong repulsive core
Weakly repulsive or attractive Core
+p (S=1, T=3/2) p (S=0, T=1/2)
p (T=0)
6 independent forces in flavor SU(3) symmetry8〇8 =x
color magnetic interaction
quark Pauli effect
J-PARC E40
Flavor singlet (H-Channel)J-PARC E42
J‐PARC E40: ±p Scattering Experiment (Miwa et al.)
production via ±p→K+±
p = 0.4 ~ 0.8 GeV/c
400 mm
K+
p
n
p
Ep Cylindrical
Fiber Tracker
BGO calorimeterCATCH detector
Very large repulsive core is predicted in N (T=3/2,S=3/2)
due to quark Pauli effect
Liq H2 target
Slide by K. Miwa
Measure d/d for p, p, p->n 20M /spill
History of E40: ‐proton scattering exp.• Feb. 2018
• Detector Commissioning • June 2018
• p 1st production run (2 days)• Feb. ー Apr. 2019
• p 2nd production run (20 days) done• p 1st production run (13 days)
terminated due to Acc. trouble• Feb. 2020 ー
• p 2nd production run (14 days) to be completed
p → p
p → n
Slide by K. MiwaKinematical matchingp (direction, E)
direction
p (direction, E)
direction
CMcos-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
(mb/
sr)
/d
d
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
p scattering at 0.55 < p(GeV/c) < 0.65)- (/ddSimulationCross section in simulation600MeV/c NSC97fESC08600 MeV/c fss2600 MeV/c chiral EFTE289 data (0.4<p(GeV/c)<0.7)
CMcos-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
(mb/
sr)
/d
d
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
n scattering (0.45 < p(GeV/c) < 0.55) p -
Simulation
Cross section in simulation
500MeV/c NSC97f
500 MeV/c fss2
ESC08
500 MeV/c chiral EFT
p → p (0.55 < p (GeV/c) < 0.65) p → n (0.55 < p (GeV/c) < 0.65)
Data (angular distribution)
out o
f acc
epta
nce
Data: Before acceptance and efficiency correction
Forward peak structure Rather flat structure
expected accuracy (simulation)
expected accuracy (simulation)
Slide by K. Miwa
H‐dibaryond
u u
dss• 6 quarks (uuddss) system with I=0, J=0+
• Deeply bound state was predicted by R.L.Jaffe in 1977→ Deeply bound state was rejected by NAGARA event (6He)
MH≧ 2M 7.25 MeV• lattice QCD simulation at almost physical point
• exist around near N threshold !?• No experimental evidence
ΞNΣΣΛΛHBB84
83
81)1(
Lattice QCD calculation for H dibaryon
10
Physical π massPhysical π mass
Calculation atalmost physics point
P.E. Shanahan, A.W. Thomas, and R.D. Young, PRL 107 (2011).
K. Sasaki for the HAL Collab., Reimei 2016, Inha (2016).
Exist aroundΞN threshold?
HAL QCD arXiv:1912.08630v1 18‐Dec‐2019
N
weakly attractive
attractive
N (quasi) bound states?
Weak N→ conversion
11S0 interaction
Lattice QCD vs ALICE data
12
Past experiment for H‐dibaryon
13
C.J. Yoon et al., PRC 75, 022201 (2007).
KEK E522:“pp”(K‐, K+)ΛΛ reaction
with SciFi active target (CH2)
Hint of H dibaryon?
B.H. Kim et al., PRL 110, 222002(2013).
Belle data: ΛΛ invariant mass
from Y(1s) and Y(2s) decayNo peak was observed
J‐PARC E42 experimentH‐dibaryon search by using “pp”(K‐, K+)H reaction with diamond target
HyperonSpectrometer
HypTPC
K⁻ beam K+
KEK E522 J‐PARC E42
14
σΔM~ 5 MeV90 ΛΛ evens
σΔM ~ 1 MeV1.5×104 ΛΛ events
Simulation
Sensitivity
From 29th J‐PARC PAC by J.K.Ahn
H→ p H→ H→ p
E42: Schedule at K1.8 of J‐PARC HEF
• Feb. ‐Mar. 2020 E40 physics run• Parasite test of TPC detector
• Apr. ‐ Oct. 2020 Setup KURAMA spectromter• Excitation test of H.S. magnet with KURAMA magnet
• Nov. 2020 E03 physics run• KURAMA detector (Water Cherenkov) & trigger study
• Dec.2020 ‐ Feb.2021 H.S. installation• Mar. ‐ Apr. 2021 E42 comm. + physics run
N interaction & ‐NucleiSeveral event‐samples on ‐ 14N system
Nuclearboundstates
Slide by J.Yoshida
Outline of the E03 experiment• World first measurement of X‐ray from Ξ− atom
→ Direct information on the Ξ‐nucleus(A) optical potential
• First step of systematic measurements to obtain 10% statistics of the original proposal.
→ Establishing experimental method in this experiment
Method: ‐ Produce Ξ− by the Fe(K−,K+) reaction
Magnetic spectrometers for K±
‐ Stop Ξ− in the target → Ξ− atomDense Fe target
‐Measure X raysGe detectors
Ξ− atom
X rayabsorption
Ξ−
Fed ss
X ray
Ξ−K−
K+
Fe target
Level scheme of Fe Ξ− atomEn
ergy [a
rbitrary scale]
I (orbital angular momentum)
Ξ−
Fe
n=5
n=7→6 : X‐ray energy = 172 keV ← small shift/widthn=6→5 : X‐ray energy = ~286 keV ← finite shift/width due to ΞN interaction
expected shift ~ 4keV, width(Γ) ~ 4keV(theoretical case study with W.S. pot. of ‐24‐3i MeV)
Ξ−
Fe
n=6
n=7
Nuclear absorption
Nuclear absorption
w/o st. int.Energy shift
Level scheme of Fe Ξ− atomEn
ergy [a
rbitrary scale]
I (orbital angular momentum)
Ξ−
Fe
n=5
n=7→6 : X‐ray energy = 172 keV ← small shift/widthn=6→5 : X‐ray energy = ~286 keV ← finite shift/width due to ΞN interaction
expected shift ~ 4keV, width(Γ) ~ 4keV(theoretical case study with W.S. pot. of ‐24‐3i MeV)
Ξ−
Fe
n=6
n=7
Nuclear absorption
Nuclear absorption
w/o st. int.Energy shift
Observable
Ge detector
Level scheme of Fe Ξ− atomEn
ergy [a
rbitrary scale]
I (orbital angular momentum)
Ξ−
Fe
n=5
n=7→6 : X‐ray energy = 172 keV ← small shift/widthn=6→5 : X‐ray energy = ~286 keV ← finite shift/width due to ΞN interaction
expected shift ~ 4keV, width(Γ) ~ 4keV(theoretical case study with W.S. pot. of ‐24‐3i MeV)
Ξ−
Fe
n=6
n=7
Nuclear absorption
Nuclear absorption
w/o st. int.Energy shift
Observable
Sensitive to potential shape
Ξ- wave function
ΞA optical potential
tρ potential
Nijimegen D→ G‐matrix
Ge detector
Phase‐1 Physics run in Nov. 2020
Summary• Group‐B01 researches aim to investigate the origin of nuclear force, meson‐baryon molecule, and hadron properties in medium, by adding strangeness (s‐quark) .
• Three experiments to investigate baryon‐baryon interactions; YN scattering, H‐dibaryon, and ‐atom, are in progress or carried out soon at J‐PARC.
Top Related