Decay Pion Spectroscopy of double- hypernuclei at J-PARC H. - - PowerPoint PPT Presentation

Decay Pion Spectroscopy


• f double-Λ hypernuclei


at J-PARC

• H. Fujioka (Tokyo Tech),

• T. Fukuda, E. Hiyama, T. Motoba,

• T. Nagae, S. Nagao, T. Takahashi

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

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Production of double-Λ hypernuclei

10 µ 10 µ #6 #5 #7 #3 #2 #8 #1 C B A Ξ- #4

• H. Takahashi et al., Phys. Rev. Lett. 87, 212502 (2001); 


J.K. Ahn et al., Phys. Rev. C 88, 014003 (2013)

6 ΛΛHe

J-PARC E07 KEK-PS E373 A variety of double-Λ hypernuclei (5≦A≦17)
 may be produced by Ξｰ capture in light nuclei Ξ− + 16O →

11 ΛΛBe + 4He + d

(most probable) ➡ Yoshida-san’s talk

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

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Counter experiments in 2020’s

Heavy Ion Collision

5 ΛΛH → 5 ΛHe + π−

CBM at FAIR
 HIAF (Huizhou, China)


Kaon-induced Production

at J-PARC

HIAF in Huizhou/China

High Intensity Heavy Ion Accelerator Facility

@ 2024

Approved by Chinese government in December 2015 Under construction

New Hypernuclear Project Spokesperson: Take Saito

The HYP setup at PANDA

p

Hypernuclei program at the CBM experiment

1

STS RICH TRD TOF ECAL PSD

Outline

• CBM physics
• Motivation for HYP program
• CBM tracking and particles ID
• Multi-strange hyperons and

Hypernuclei simulation

• Conclusion
• J. Pochodzalla, HYP2015
• I. Vassiliev, HYP2015

T.R.Saito, HYP2018

Letter of Intent for J-PARC 50 GeV Synchrotron

Decay Pion Spectroscopy of

5 ΛΛH

produced by 7Li(K−, K+) reactions

Hiroyuki Fujioka1∗, Tomokazu Fukuda2,4†, Emiko Hiyama3,4, Toshio Motoba2,5, Tomofumi Nagae6, Sho Nagao7, Toshiyuki Takahashi8

June 15, 2018

Abstract Proposed is a novel method to produce a double-Λ hypernucleus without using nuclear emulsion. A Ξ− bound in 6He and a part of quasi-free Ξ−’s, produced in 7Li(K−,K+) reactions, are absorbed in the reaction point, and

weak decay of 5

The experimental setup will be based on the Ξ-hypernuclear spectroscopy experiment E70; a new cylindrical detector system will be installed between the K1.8 beamline spectrometer and the S-2S spectrometer for detection of the decay pion and the proton.

http://j-parc.jp/researcher/
 Hadron/en/Proposal_e.html

P̅ANDA at FAIR

p̅-induced
 Ξ− production + Ξ− capture Decay Pion Spectroscopy

7Li(K−, K+) 5 ΛΛH + 2n

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Decay pion spectroscopy

Pion momentum in SpekC (MeV/c)

105 110 115 120 125 130 135 140 145 150

Events / (250 keV/c)

5 10 15 20 25 30 35 peak maximum = 37 events background at peak = 7.3 events

et al. NP B52 (1973) c

• M. Juri
• G. Bohm et al. NP B4 (1968)
• W. Gajewski et al. NP B1 (1967)

2 4

H) (MeV)

4

( B

Events

20 40

H from nuclear emulsion

4 Λ

World data on

Λ Λ

4 ΛH → 4He + π−

• A. Esser et al.,


PRL 114, 232501 (2015) A1 Collaboration,
 NPA 954, 149 (2016) at MAMI ➡ Nagao-san’s talk on Wednesday

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ΛΛ-ΞN mixing in

N N S=-1 S=0 S=-2 ~300 MeV ~75 MeV ~75 MeV H? ~28 MeV ~28 MeV

mix.~a few % Large Mixing ? Large 3-body force ?

5049.1MeV

4He+Ξ−

5040.3MeV

3H+ΛΛ

5037MeV? 5048MeV?

~11MeV?

3H+Ξ−+p

29MeV 21MeV

5 ΛΛH 5 Ξ−H

• ○
• 0s1/2
• ΛΛ→Ξ−p

p n Λ

5ΛΛH 6ΛΛHe

• 0s1/2
• p

n Λ

5 ΛΛH

B.F. Gibson et al., 


• Prog. Theor. Phys. Suppl. 117, 339 (1994)

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

Production via Ξ-hypernuclear decay

◆ Only 4 decay channels are allowed energetically ◆ Among them, the channel with the fewest bodies and the largest Q-value is most predominant (B.R. ~ 90% !!)

• 6

Double-L hypernuclear formation via a neutron-rich J state

Izumi Kumagai-Fuse and Yoshinori Akaishi

Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, Japan ~Received 21 March 1996! Conversion processes for J

7 H are discussed as a typical example of the double-L hypernuclear formation via

a neutron-rich J state. LL

5 H is formed with a surprisingly large branching ratio of about 90% from J 7 H that is

produced by the (K2,K1) reaction on the 7Li target. The J

7 H state has a narrow width, 0.75 MeV, and its

population can be confirmed by tagging K1 momentum. @S0556-2813~96!50507-8# PACS number~s!: 21.80.1a. 21.45.1v. 25.80.Nv, 25.80.Pw PHYSICAL REVIEW C JULY 1996 VOLUME 54, NUMBER 1

J 7 H→LL 5 H1n1n ;11 MeV,

→L

4 H1L1n1n ;7 MeV,

→L

4 H*1L1n1n ;6 MeV,

→3H1L1L1n1n ;5 MeV.

• I. Kumagai-Fuse, Y. Akaishi, Phys. Rev. C 54, R24 (1996)

“Selective” production!

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

A new experiment at J-PARC

• 1. Production of by the reaction

• 2. ΞN→ΛΛ conversion in , yielding

• 3. Two-body weak decay of 

• 4. Weak decay of
• 7

7 Ξ−H 7Li(K−, K+) 5 ΛΛH + 2n 7 Ξ−H 5 ΛΛH → 5 ΛHe + π− 5 ΛHe

Tagging of by means of missing-mass spectroscopy

7 Ξ−H

may be produced as well

4 ΛH

Identifjcation of and by detecting π− (>130MeV/c)

4 ΛH 5 ΛΛH

Tagging a fast proton from NMWD of 5

ΛHe

Decay pion spectroscopy for 5

ΛΛH

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

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reaction

α+n+n+Ξ –

0 MeV –0.96

6He+Ξ –

αΞ –

( +n+n –1.71 –3.06

1/2+

–0.57 –1.83 –0.19 –1.29

(i) kF (ii) kF (iii) kF

(a) H (ESC)

5 H Ξ

=0.9 =1.055 =1.3

)cal

7 Ξ−

α+n+n+Ξ –

0 MeV –0.96

6He+Ξ –

α Ξ –

( +n+n –0.57 –2.52

1/2+

–0.32 –2.02 –0.15 –1.50

(b) H (ND)

5H

Ξ

)cal

7

Ξ−

• E. Hiyama et al., Phys. Rev. C 78, 054316 (2008)
• Fig. 1 Calculated 7Li(K −, K +) inclusive spectra for pK − = 1.65 GeV/c and θK + = 0◦. The left and right panel show the results

corresponding to the case using potential ND and ESC with three k f parameters listed in Table 1, respectively. These spectra are smeared assuming 2 MeV detector resolution

Koike and Hiyama, Few-Body Syst. 54, 1275 (2013)

7Li(K−, K+) 7 Ξ−H

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Momentum of two-body-decay pions

• Y. Yamamoto, M. Wakai, T. Motoba and T. Fukuda, Nucl. Phys. A 625, 107 (1997)

Region of Interest

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Past counter experiment in BNL-AGS

J.K. Ahn et al., Phys. Rev. Lett. 87, 132504 (2001)

9Be(K−, K+){Ξ− + 8Li*} ⟶ [ 8 ΛΛHe*] + n

⟶ [

8 ΛΛH*] + p

“double-Λ compound nucleus” → fragmented into double-Λ hypernuclei,
 single-Λ hypernuclei etc.

• Y. Yamamoto, M. Wakai, T. Motoba, T. Fukuda,

• Nucl. Phys. A 625, 107 (1997)

ΞN rescattering
 & ΞN-ΛΛ conversion

BNL-AGS E906

80 90 100 110 120 130 140 150 160 80 90 100 110 120 130 140 150 160

II I III IV

PL (MeV/c) PH (MeV/c)

10 15 20 25 10 15 20 25 10 15 20 25 10 15 20 25

4 ΛH 3 ΛH

4 ΛΛH?

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Two-pion coincidence measurement

October 17, 2003 14

HYP2003

Suggested decay mode of 4

ΛΛH and limits on ∆BΛΛ

4 ΛΛH (single Λ binds to 2H by 0.13 MeV) 3 ΛH + p

}? MeV

3 ΛH (7.75 MeV) 4 ΛHe 3He

π− (104 MeV/c) p π− (114.3 MeV/c)

4 ΛHe excitation(MeV) ∆BΛΛ(MeV)

7.75 1.8 8.75 0.8 9.84 -0.26

4 ΛHe*

• P. Pile, HYP2003

80 90 100 110 120 130 140 150 160 80 90 100 110 120 130 140 150 160

II I III IV

PL (MeV/c) PH (MeV/c)

10 15 20 25 10 15 20 25 10 15 20 25 10 15 20 25

4 ΛΛH?

Decay pion spectroscopy Identifjcation of 3

ΛH

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

How to identify ?

◆ BNL-AGS E906 (P961R)
 two pions from sequential MWD
 → clue to identify
 parent double-Λ hypernuclei and
 daughter single-Λ hypernuclei ◆ This method is difficult to apply
 in case of 5ΛΛH decay

• 12

5 ΛΛH

80 90 100 110 120 130 140 150 160 80 90 100 110 120 130 140 150 160

II I III IV

PL (MeV/c) PH (MeV/c)

10 15 20 25 10 15 20 25 10 15 20 25 10 15 20 25

4 ΛΛH?

80 90 100 110 120 130 140 150 160 80 100 120 140 160

PπL (MeV/c) PπH (MeV/c)

25 50 75 100 125 150 175 200 225 10 20 30 40 50 60

simulation (P961R proposal)

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80 90 100 110 120 130 140 150 160 80 100 120 140 160

PπL (MeV/c) PπH (MeV/c)

5H → 4H + p +π-(99) ΛΛ Λ 4H → 4He +π-(133) Λ 5H → 5He +π-(135?) ΛΛ Λ 5He → 4He + p +π-(99) Λ 4H → 4He + π-( 116? ) ΛΛ Λ 4He → 3He + p +π-(97) Λ 4H → 4He* + π-(104) ΛΛ Λ 4He* → 3H + p Λ Λ 3H → 3He + π-(114.3) Λ 5H → 4H + p +π-(99) ΛΛ Λ 4H → 3H + p +π-(101) Λ

25 50 75 100 125 150 175 200 225 10 20 30 40 50 60

5 ΛΛH → 4 ΛH + p + π− 4 ΛH → 4He + π− 5 ΛΛH → 5 ΛHe + π− 5 ΛHe → 4He + p + π−

≈ 99MeV/c ≈ 133MeV/c

From a point of view of
 decay pion spectroscopy,
 the decay mode on the left side
 is regarded as a background process.

The distinction between the two decay modes
 are experimentally difficult.

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

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→L

4 H1L1n1n ;7 MeV,

→L

4 H*1L1n1n ;6 MeV,

[

6 ΛΛH*] → 4 ΛH + Λ + n

(a) (b) (c)

5 ΛΛH → 4 ΛH + p + π− 4 ΛH → 4He + π−

J 7 H→

via Ξ hypernuclei via double-Λ compound nuclei via 5ΛΛH 3-body decay

Novel method for identifjcation

5 ΛΛH

5 ΛΛH → 5 ΛHe + π− 5 ΛHe → 3H + p + n

via 5ΛΛH 2-body decay signal background fast proton w/o pion (Non-Mesonic Weak Decay) slow proton w/ pion (Mesonic Weak Decay) Λ → p+π− Λ → p+π−

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

A new experiment at J-PARC

• 1. Production of by the reaction

• 2. ΞN→ΛΛ conversion in , yielding

• 3. Two-body weak decay of 

• 4. Weak decay of
• 15

7 Ξ−H 7Li(K−, K+) 5 ΛΛH + 2n 7 Ξ−H 5 ΛΛH → 5 ΛHe + π− 5 ΛHe

Tagging of by means of missing-mass spectroscopy

7 Ξ−H

may be produced as well

4 ΛH

Identifjcation of and by detecting π− (>130MeV/c)

4 ΛH 5 ΛΛH

Tagging a fast proton from NMWD of 5

ΛHe

Decay pion spectroscopy for 5

ΛΛH

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

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Experimental setup

3 m Q13 Q12 D4 BH2 BC4 BC3 Q11 Q10 Q9 BH1 S-2S SDC1 SDC2 SDC3 SDC4 TOF AC WC Target

requirements

• 1. High resolution for (K-,K+) spectroscopy


in order to distinguish from QF events
 → Sｰ2S will be the best option

• 2. Decay π− and proton measurement


→ a large-acceptance and compact
 CDS (cylindrical detector system) @J-PARC K1.8 beamline

7 Ξ−H

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Hiroyuki Fujioka (Tokyo Tech.) / QNP2018

Summary and outlook

◆ production (via decay) and decay (into ) will be investigated at J-PARC,
 aiming at ΔBΛΛ determination with tens of identifjed ◆ Detailed study of identifjcation by fast-proton tagging is in progress. ◆ Submitted a Letter of Intent in June 2018. ◆ A proposal for the phase-1 exp. is in preparation.

• Decay pion spectroscopy for single-Λ hypernuclei
• Missing-mass spectroscopy for reaction
• Measurement of secondary particles from 7Li target



Hypertriton mass puzzle? 


• 17

5 ΛΛH 7 Ξ−H 5 ΛHe + π− 5 ΛΛH 7Li(K−, K+) 5 ΛΛH

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!16

200 − 200 400 600

(keV)

Λ

H B

Λ

0.05 (stat. only) MeV ± 0.13 Mean + stat. uncertainty only (NPB 52,1 (1973)) 0.15(syst.) MeV ± 0.10(stat.) ± STAR (2018): 0.44

STAR Preliminary

NPB1,105 (1967) 2-body NPB1,105 (1967) 3-body NPB4,511 (1968) 2-body NPB4,511 (1968) 3-body TIFR Report,

• No. NE-68-8 (1968)

PRD1,66 (1970) 2-body NPB52,1 (1973) 2-body NPB52,1 (1973) 3-body STAR (2018) H

3 Λ

2-body STAR (2018) H

3 Λ

3-body STAR (2018) H

3 Λ

(2+3)-body STAR (2018) H

3 Λ

H +

3 Λ

(2+3)-body

" *+

Figure 8. A summary of worldwide binding energy of "

*+ experimental measurements. The vertical lines are the

− 600

(keV)

Λ

H B

3 Λ

Λ Λ Λ Λ Λ

The BΛ data

−

Λ Λ

Λ Λ Λ Λ Λ

!" #" + #% − #

"

'( !"

The difference between STAR measurement and the previous measurement is 0.31 0.11 (stat. only) MeV

±

Jinhui Chen, HYP2018