SATOSHI N. NAKAMURA

TOHOKU UNIVERSITY

Strangeness Nuclear Physics

with Electron/Photon Beams

25th November 2019

Current problems on

L hypernuclei

10−15 m 104 m

A=3 A~1057

Λ3𝑛 Puzzle

CSB of L Hypernuclei Hyperon PuzzleHypertriton Puzzle

pn

Λ

Λn

nΛ

np

LL

?p

n

p

n

Shallow boundShort lifetime

Bound?Resonance?Not Exist?

Why massive NS exists?

Current problems on

L hypernuclei

10−15 m 104 m

A=3 A~1057

Λ3𝑛 Puzzle

CSB of L Hypernuclei Hyperon PuzzleHypertriton Puzzle

pn

Λ

Λn

nΛ

np

LL

?p

n

p

n

Shallow boundShort lifetime

Bound?Resonance?Not Exist? Why massive

NS exists?JLab

MAMI

ELPH

JLab

Electron beam vs. meson beams (e,e’K+)

Excellent mass resolution ~ 0.5 MeV

Absolute energy calibrationp(e,e’K+) L, S0

(K-, p-)

(p+, K+)

1-2 MeV resolution

Normalized to 12LC mass

Thin target (isotopically enriched)

eg. 40,48Ca, 3H

(e,e’K+) reaction spectroscopy

0.5 MeV (FWHM)

1.45 MeV (FWHM)

12C(𝜋+,K+)12ΛC

KEK-PS

E369

Absolute MM calibration

12LCgs energy

from emulsion

0.7 MeV (FWHM)

12C(e,e’K+)12ΛB

1.45 MeV (FWHM)

12C(𝜋+,K+)12ΛC

KEK-PS

E369

Absolute MM calibration

12LCgs energy

from emulsion

0.7 MeV (FWHM)

12C(e,e’K+)12ΛB

0.5 MeV (FWHM)

Λ12C (emulsion):= 10.76 ± 0.19MeV

Nucl. Phys. A (1988) 520.

1.45 MeV (FWHM)

12C(𝜋+,K+)12ΛC

KEK-PS

E369

Absolute MM calibration

12LCgs energy

from emulsion

0.7 MeV (FWHM)

12C(e,e’K+)12ΛB

0.5 MeV (FWHM)

Λ12C (emulsion):= 10.76 ± 0.19MeV

Nucl. Phys. A (1988) 520.

0.5-0.6MeV shift

T.Gogami et al. PRC93(2016).

E.Botta et al. NPA969 (2017).

Hyperon Puzzle

Two solar mass neutron stars

nn

Λ

Λ3𝑛 Puzzle

Tang’s talk

JLab Hypernuclear

Collaboration

E12-15-008: 40,48 Ca targets

C12-19-002 Light targets

Gogami’s talk

P12-18-004 Heavy targets

Many talks in this WS

Hyperon PuzzleBased on our knowledge on Baryonic Force:

Hyperon naturally appear at high density (r=2~3r0)

２ 𝑀⨀ Neutron Stars

Too Soft EOS

Contradict

to

observation

Additional Force

to make EOS stiff

AFDMC by Lonardoni

AFDMC by Lonardoni et al. PRL114 (2015) 092301, updated (2016)

ESC08c + 3B/4B RF : G-Matrix Calc. by Yamamoto et al., PRC 90 (2014) 045805.Variational Meth. + AV18+UIX by Togashi et al., PRC 93 (2016) 035808

J0740+6620 (2019/9/18 2.14 𝑀⨀sol, Green Bank Obs.)

From Hypernuclei to NS

E12-15-008

C12-19-002

P12-18-004

Phenomenological 3 BRF+AFDMC

E12-15-008

accepted with GRADE A.

40Ca(e ,e′K+)40LK and , 48Ca(e, e′K+)48

LK

CT :Parameter to gauge

Lnn contribution

in LNN potential

D.Lonardoni

Other calculations are important

to analyze new data.

JLab E12-15-008

New Pair Charge Sep. Mag. 40,48Ca targets

under construction

New setup for E12-15-008

PCSM

To be done before

E12-15-008 beamtimeItem Status Schedule

Pair of Charge Sep. Magnets Contracted

Under const.

Will complete

16 Mar. 2020.

Vacuum Chamber For Solid targets Und. Design

For Cryo. targets Depends on PAC48

Targets 40,48Ca ready

HKS Water Cerenkov Prototype ready Spring 2020

Stand for HKS

Sieve slits, collimators

Analysis/Simulation codes Under develop. In 2020

Ready for Beam in 2021

ELPH NKS2 CollaborationExp# 2895, S.Nagao et al.

p

nΛ

Λ3H puzzle

JLab 3He(e,e’K+)Λ3H

(Gogami’s talk)

MAMI decay p(Herrmann’s talk)

Short t

Small BL

Proposed at J-PARC

Partially approved,

under preparation at ELPH

3He(K-, p0)Λ3H and 3He(p-, K0)Λ

3H

3,4He(𝛾,K+) Λ3,4H

Lifetime measurement of Λ3H, Λ

4H with 3,4He(𝛾,K+) Λ

3,4H reaction

p.16

1 m

K+

NKS2 MagnetTOF

Liq. He

γ beam

4π decay detectorTracking

Chamber

BLT

AC

Comparison 𝑒, 𝑒′𝐾+ , (𝛾, 𝐾+) reactions

2019/3/5 RCNP研究会

(e,e'K+) (g,K+)

Beam Intensity 1013～14 e-

→ 109 g*

107 g

Target Thickness 0.1 g/cm2 > g/cm2

Energy resolution 10-4 10-3～-2

Spectrometer

Solid angle

～ 10 msr >100 msr

Yield a few 100 / week a few 100 / week

Modest Resolution, but less BGSuitable for decay study of hypernuclei

1.1~1.5 GeV tagged photon beam

No need to

Measure

Neutral particles

cf) 3He(K-, p0)Λ3H

3He(p-, K0)Λ3H

Photon Beam Facility (ELPH, Tohoku Univ.)

p.18

BST Ring

Hypernuclear experiment at ELPH

p.19

http://hayabusa1.lns.tohoku.ac.jp/

BST Ring

NKS2

• Forward K+ Spectrometer

• Large Solid Angle

• Δp/p ~ 1%

4π Decay counter

• Detecting decay particle from hypernuclei

• Large Solid Angle

• Good time resolution & eーπーp separation

• Range counter for PID

Lifetime measurement of Λ3H (Λ

4H)

1 m

K+

NKS2 MagnetTOF

Liq. 3He

γ beam

4π decay counterTracking

Chamber

BLT

AC

Missing Mass (Λ3H ID)

Co

un

ts /

MeV

BΛ (MeV)

3HΛ

q.f. Λ

(650 / 50 days

Missing Mass spectrum

Lifetime measurement of Λ3H (Λ

4H)

p.21

1 m

K+

NKS2 MagnetTOF

Liq. 3He

γ beam

4π decay counter

BLT

AC

Decay Time= Tdecay - Tgen

1 m

TrackingChamber

Drift Chamber

Range Counter

TDL BLT

𝚲𝟑𝐇

π－

γ beam K+

Tdecay

Tgen

BLT

AC

Decay time (ns)-0.5 0.0 0.5 1.0 1.5 2.0

100

10

1

Co

un

ts /

20 p

s

Decay time spectrum

Δτ = 10 ps (τ=200ps)

Fast timing detector (TDL)

p.22

4π good time resolution detector

➢ Φ=9 cm, L=20 cm

➢ 48 x scintillator bar

• 5x5x20 mm3 each

➢ 48 x 2-series connection SiPM

• MPPC S13360-3050CS

4ch diff. Amp.

MPPC

Scintillator

Schedule

2019/3/5

RCNP

RCNP研究会 p.23

4He target for Λ4H lifetime measurement : Feasibility test

𝚲𝟒𝐇 lifetime

𝚲𝟑𝐇 lifetime

2017

2020

2021

Λ lifetime

Detector Construction

Λ lifetime

2019

2018-2019

SNP study with e,g beamsJLab E12-15-008(e,e’K+)

E12-17-003 (nnL)MAMI-Mainz

Challenge Hyperon, nnL, 3LH, CSB Puzzles!

ELPH-Tohoku

3LH lifetime

FSI LN int.

Light

Hypernuclei

Decay p Spectroscopy ofelectroproduced HY

Compare experimental results with

Theoretical Predictions of Binding Energies and Cross Sections

Deduce ΛN interaction including many-body forces

First Isospin dependence

of medium heavy HY

w/ best resolutionElementary

Strangeness

photo-production3

LH Binding E.Study of LN through nnL