[PPT] - experiment at J-PARC 2019/9/26 T. O. Yamamoto JAEA (Japan) for PowerPoint Presentation

SLIDE 1

Recent result and future plan of hypernuclear γ-ray spectroscopic experiment at J-PARC

2019/9/26

T. O. Yamamoto

JAEA (Japan) for the J-PARC E13/E63 collaboration

After the previous J-PARC symposium, J-PARC E13 was successfully performed. Thank you for great support !

SLIDE 2

Hypernuclear structure and spin-dependent N interaction

Z

A Λ

Z

1

A

Level scheme of hypernucleus

Core nucleus (ordinal nucleus)  hypernucleus

We can get Information of spin-dependent N interaction from level scheme

Spin  0

spin-doublet

spin-spin spin-orbit (s) spin-orbit (sN) Tensor

1 core nuclear state 2 hypernuclear states

Spin-dependent interaction ( spin of  =  1/2 ( in s state) )

Energy spacing : 10 keV ~ 1 MeV

central

High resolution -ray spectroscopy

SLIDE 4

Hypernuclear structure and spin-dependent N interaction

Z

A Λ

Z

1

A

Level scheme of hypernucleus

Core nucleus (ordinal nucleus)  hypernucleus

We can get Information of spin-dependent N interaction from level scheme

Spin  0

spin-doublet

spin-spin spin-orbit (s) spin-orbit (sN) Tensor

1 core nuclear state 2 hypernuclear states

Spin-dependent interaction ( spin of  =  1/2 ( in s state) )

Energy spacing : 10 keV ~ 1 MeV

central

High resolution -ray spectroscopy

Hypernuclear -ray spectroscopy at KEK and BNL (1998~) Strengths of spin-dependent terms were determined (for p-shell)

> Study of different (s-, sd-) shell hypernuclei at J-PARC

O N, C, B, Be, Li,

16 15 12 11 9       7

SLIDE 5

Study of radial dependence of N spin-spin interaction ( J-PARC E13 )

19 F 7 Li First measurement in sd-shell hypernuclei

 n p  n p

Wave functions of Nucleon and (s-state)



4 He

J-PARC E13

First precise measurement using Ge detector

J-PARC E13

Well studied in previous experiments

sd-shell p-shell s-shell Radial dependence can be studied from these difference

n

Effect of spin-dependent interaction

n hypernuclear level structure

(s-shell)  N(most outer shell) Charge symmetry breaking?

SLIDE 6

K－

Use high intensity K- beam delivered from J-PARC K1.8 beam line

−

  + → 

 − −

Z Z Z

A A A ＊

) , (K

Spectrometer for scat. particle

（SksMinus）

Detect t  ray from hypern rnuc uclei ei

・ Hyperball-J

Tag hypernu nucl clea ear productio tion

・ Beam line spectrometer ・ SksMinus spectrometer

reaction-γ coincidence experiment

Beam line spectrometer

Experimental setup (E13)

Ge detector array

Hyperball-J

4 He : liq.He terget (2.5 g/cm2)

pK = 1.5 GeV/c

19 F : lip. CF4 target (20 g/cm2)

pK = 1.8 GeV/c

SLIDE 7

Hyperball-J new Ge detector array

high count and energy deposit rate
radiation damage due to hadron beam

Lower half of Hyperball-J PWO counter Ge detector Pulse-tube cooler

Target

Features

Large photo-peak efficiency

→ ε ~6 % @1 MeV with 32 Ge detectors

Fast readout system Low temp. Ge detector → Mechanical cooling Fast background suppressor → PWO counter For high intensity hadron beam

SLIDE 8

Data taking (2015)

(Re-)started just after recovery from the accident at hadron facility Hyperball-J＠K1.8

Liq. Target system

Beam time for physics data taking

4 He : ~5 days 19 F : ~14 days

SLIDE 9

Recent results Gamma-ray spectroscopy on 4

ΛHe, 19 ΛF

(J-PARC E13)

SLIDE 10

Result of 4

ΛHe (s-shell)

Press release http://www.sci.tohoku.ac.jp/news/20151125-7613.html

SLIDE 11

Result of 4

ΛHe (s-shell)

Level schema of mirror hypernuclei

4 H / 4 He

Ex(4

ΛHe; 1+) = 1.406  0.004 MeV

T. O. Yamamoto et al., Phys. Rev. Lett.

115, 222501 (2015)

Obtained energy spectrum

Existence of CSB effect was confirmed ( BΛ(g.s) and γ-ray )
Strongly spin-dependent : B(1+) = 0.03  0.05 MeV

B(0+) = 0.35  0.05 MeV

SLIDE 12

Result of 4

ΛHe (s-shell)

Level schema of mirror hypernuclei

4 H / 4 He

Y. Akaishi, et. al.,
Phys. Rev. Lett. 84, 3539 (2000).

3 body ΛΣ coupling has important roll + same spin tendency Key of CSB effect? No large effect with NSC model? Many theoretical work based on ab-initio calc. (accuracy: ~10 keV)

Need high accurate data (<10 keV)

Precise γ-ray spectroscopy is powerful tool to study CSB

We will continue with our technique in future measurement

A. Gal, Phys. Lett. B 744,

352 (2015).

A. Nogga et al.,
Phys. Rev. Lett. 88,

172501 (2002).

D. Gazda, A. Gal,

NPA 954 (2016) 161

SLIDE 13

Result of 19

ΛF (sd-shell)

Press release https://www2.kek.jp/ipns/ja/release/hyper/

SLIDE 14

Result of 19

ΛF (sd-shell)

Energy of g.s. spin-doublet was determined (First data on sd-shell)

19 ΛF 19 ΛF 19 ΛF 19 ΛF

Obtained energy spectrum Ex(19

ΛF; 3/2+)

= 315.5 ±0.4 −𝟏.𝟔

+0.6

keV

S.B. Yang et al., Phys. Rev. Lett. 120, 132505 (2018)

SLIDE 15

Radial dependence

Now, we have s-, p-, sd-shell data. Shell model calc. (Umeya & Motoba) reproduce experimental data.

3 s-shell p-shell sd-shell with NSC(e,f) model * adjusted to p-shell data

Our knowledge and theoretical flamework is also good in s- and sd-shell

Ecal = 692 keV (adjusted) Ecal = 346 keV Ave(Eexp) = 1248 keV Ecal = 1232 keV Spin-dependent ~50% ΛΣ coupling ~50%

T. Koike, HYP2018

J-PARC E13 J-PARC E13

SLIDE 16

Future measurement Gamma-ray spectroscopy on 4

ΛH, 7 ΛLi

(J-PARC E63)

SLIDE 17

J-PARC E63 (E13-2) Submitted in 2015 stage-2 approval

31 participants from 12 institutes

4

H excitation energy

(Strength of CSB effect)

7

Li lifetime

(Λ magnetic moment in nuclear medium)

SLIDE 18

CSB effect in A=4 system

Level schema of mirror hypernuclei 4

H / 4 He

We obtained high precision data （ J-PARC E13） rather large deviation Three old data are available [1] [2] [3] [1] [2] [3] Expected

Excitation energy [MeV]

Need to update!

SLIDE 19

γ-ray spectroscopy of 4

H

4 H generates as hyperfragment

via the in-flight 7Li(K-,-)7

ΛLi reaction

7Li target

SKS spectrometer beam line spectrometer Range counter (inside Hyperball-J) Ge detector array (Hyperball-J)

γ-ray

Almost common with J-PARC E13

Tagging monochromatic π− (Support hypernuclear identification) stop

SLIDE 20

γ-ray spectroscopy of 7

ΛLi

 magnetic moment in nuclear density

 in free space  in nuclear medium Different?

𝝂𝜧 = 𝒇ℏ 𝟑𝒏𝒕𝒅

(𝒏𝒕: 𝒅𝒑𝒐𝒕𝒖𝒋𝒖𝒗𝒇𝒐𝒖 𝒓𝒗𝒃𝒔𝒍 𝒏𝒃𝒕𝒕)

Life time of M1 transition [7

ΛLi; 3/2+→1/2+] (~0.5 ps)

→  magnetic moment 𝟐 𝝊 = 𝟐𝟕𝝆 𝟘 𝑭𝜹

𝟒

𝟒 𝟗𝝆 𝟑𝑲𝒎𝒑𝒙 + 𝟐 𝟑𝑲𝒅 + 𝟐 (𝒉𝒅 − 𝒉𝚳)𝟑

Assuming weak coupling between core and 

Mass change ? shape analysis on Doppler broaden peak

Key point: High stopping power → Dense target Li2O crystal (ρ=2.013 g/cm3)

SLIDE 21

Preparation status

0.9-1.1 GeV/c K- beam to adjust Doppler broadening → move to J-PARC K1.1 beam line with SKS magnet K1.8 K1.1 K1.8BR KL High-p

J-PARC hadron experimental facility 30 GeV proton Production target (Au)

SKS: moved to K1.1 Hyperball-J: Established Range counter: Designing (will be constructed in next year) Li2O target: making crystal @JAEA

SLIDE 22

Summary

➢ Gamma-ray spectroscopy is powerful tool for study of spin-dependent term and CSB in ΛN interaction ➢ Measurement for s- and sd-shell hypernuclei (E13) was successfully done.

4

ΛHe

CSB in excitation energy + spin-dependence

19

ΛF

Test theoretical framework

➢ Future measurement (J-PARC E63) [stage-2 approval]

4

ΛH

Precise data for CSB study

7

ΛLi

Recent result and future plan of hypernuclear γ-ray spectroscopic experiment at J-PARC

2019/9/26

JAEA (Japan) for the J-PARC E13/E63 collaboration

After the previous J-PARC symposium, J-PARC E13 was successfully performed. Thank you for great support !

Contents

➢ Introduction Hypernuclear γ-ray spectroscopy at J-PARC ➢ Recent results [J-PARC E13, 2015]

➢ Future measurement [J-PARC E63]

➢ Summary

Hypernuclear structure and spin-dependent N interaction

Z

Z

Level scheme of hypernucleus

Core nucleus (ordinal nucleus)  hypernucleus

We can get Information of spin-dependent N interaction from level scheme

spin-doublet

spin-spin spin-orbit (s) spin-orbit (sN) Tensor

1 core nuclear state 2 hypernuclear states

Spin-dependent interaction ( spin of  =  1/2 ( in s state) )

High resolution -ray spectroscopy

Hypernuclear structure and spin-dependent N interaction

Z

Z

Level scheme of hypernucleus

Core nucleus (ordinal nucleus)  hypernucleus

We can get Information of spin-dependent N interaction from level scheme

spin-doublet

spin-spin spin-orbit (s) spin-orbit (sN) Tensor

1 core nuclear state 2 hypernuclear states

Spin-dependent interaction ( spin of  =  1/2 ( in s state) )

High resolution -ray spectroscopy

Hypernuclear -ray spectroscopy at KEK and BNL (1998~) Strengths of spin-dependent terms were determined (for p-shell)

O N, C, B, Be, Li,

Study of radial dependence of N spin-spin interaction ( J-PARC E13 )

 n p  n p



J-PARC E13

J-PARC E13

sd-shell p-shell s-shell Radial dependence can be studied from these difference

n

Effect of spin-dependent interaction

(s-shell)  N(most outer shell) Charge symmetry breaking?

K－

−

  + → 

Z Z Z

) , (K

Detect t  ray from hypern rnuc uclei ei

・ Hyperball-J

Tag hypernu nucl clea ear productio tion

・ Beam line spectrometer ・ SksMinus spectrometer

reaction-γ coincidence experiment

Experimental setup (E13)

Hyperball-J

pK = 1.5 GeV/c

pK = 1.8 GeV/c

Hyperball-J new Ge detector array

Lower half of Hyperball-J PWO counter Ge detector Pulse-tube cooler

Features

Large photo-peak efficiency

→ ε ~6 % @1 MeV with 32 Ge detectors

Fast readout system Low temp. Ge detector → Mechanical cooling Fast background suppressor → PWO counter For high intensity hadron beam

Data taking (2015)

(Re-)started just after recovery from the accident at hadron facility Hyperball-J＠K1.8

Beam time for physics data taking

Recent results Gamma-ray spectroscopy on 4

ΛHe, 19 ΛF

(J-PARC E13)

Result of 4

ΛHe (s-shell)

Result of 4

ΛHe (s-shell)

Level schema of mirror hypernuclei

Ex(4

Obtained energy spectrum

B(0+) = 0.35  0.05 MeV

Result of 4

ΛHe (s-shell)

Level schema of mirror hypernuclei

3 body ΛΣ coupling has important roll + same spin tendency Key of CSB effect? No large effect with NSC model? Many theoretical work based on ab-initio calc. (accuracy: ~10 keV)

Need high accurate data (<10 keV)