Status of J-PARC E07 Junya Yoshida J-PARC - - PowerPoint PPT Presentation

Status of J-PARC E07：

ダブルΛハイパー核検出実験の現状

Junya Yoshida

J-PARC E07 Collaboration

Physics department, Gifu University, Japan 15001001, 24105002z

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range

NN interaction

N N

~1fm

Λ Λ

?

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ｎ ｎ ｐ ｐ ΛΛ

6ΛΛHe (4He + Λ + Λ)

d-quark s-quark s-quark

15ΞC (14N + Ξ-)

ｎ ｎ ｐ ｐ ｎ Ξ-

LL hypernuclei X hypernuclei

u-quark d-quark s-quark

Double strangeness nuclei:

*Exotic nuclei made up of two s-quarks (lifetime =~10-10 sec) *Tiny neutron-star on the ground

N Ξ

?

*Essential subject to understand baryon-baryon interactions and EOS of NS

25.0cm*24.5cm Optical microscope stage CCD camera Objective lens （x10,x50,x100）

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*Photographic film having sub-micron of special resolution *Thick sheets: T=~1mm -> ~0.5mm (after development) *7stages in Gifu-University and JAEA

Photographic emulsion sheet for double strangeness nuclei

Sheet after photographic development

Focal depth: 6 mm, equal to 18 mm before dev. … micrograph Emulsion sheet 345mm 350mm

Thickness :1.0mm→ 0.6mm after dev.

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100mm Under 20x objective lens

100mm Focal depth: 6 mm, equal to 18 mm before dev. … micrograph Emulsion sheet 345mm 350mm

Thickness :1.0mm→ 0.6mm after dev.

Under 20x objective lens

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100mm Focal depth: 6 mm, equal to 18 mm before dev. … micrograph Emulsion sheet 345mm 350mm

Thickness :1.0mm→ 0.6mm after dev.

Under 20x objective lens

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100mm Focal depth: 6 mm, equal to 18 mm before dev. … micrograph Emulsion sheet 345mm 350mm

Thickness :1.0mm→ 0.6mm after dev.

Under 20x objective lens

X-

K+

K- beam 1.8GeV/c Emulsion stack 35cm*34.5cm*13layers SSD SSD

?

Hybrid method for J-PARC E07, double strangeness nuclei search Cross section ~0.16 mb

K- beam

Silicon Strip Detector(SSD)

Diamond target

Emulsion stack (13layers)

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Hypernuclei as nuclear fragment

ｎ ｐ ｎ ｐ ｎ ｐ ｐ ｎΛ Λ ｎ ｐ ｐ ｎΛ Λ Λ Λ ｐ ｎ ｎ ｐ ｐ ｎ Ξ- ｎ ｐ ｎ ｐ ｎ ｎ ｐ ｎ ｐ ｐ ｎΛ Λ ｎ ｐ ｐ ｎ ｎ ｎ ｐ ｐ ｎ Λ ｐ π- ｎｐ ｎ ｐ π- ｎ ｐ ｐ ｎ ｎ ｐ Twin L hypernuclei LL hypernucleus X capture p + Ξ- → Λ + Λ + 28MeV

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Kiso Event

r Λ

BX

ｎ ｎ ｐ ｐ ｎ

Ξ-

ｎ ｐ ｎ ｐ ｎ ｐ ｎ ｐ ｐ ｎΛ

Λ d-quark s-quark s-quark

Bound state Ξ- and 14N with strong interaction

BΞ- = 1.11~4.38 +- 0.25 MeV

• PTEP. (2015) 033D02.

M(LX) + M(LX’) + Qvalue M(AZ) + MX- BX Kiso event：X- +14N ⇒1

L 0Be + 5 LHe

2015年1月19日 中日新聞 朝刊

X -

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Nagara event

６ ΛΛHe

LL interaction is weekly attractive

ΔBΛΛ = 0.67 +- 0.17 MeV Where, BΞ- = 0.13MeV ｎ ｎ ｐ ｐ ｎ

Ξ-

ｎ ｐ ｎ ｐ ｎ ｎ ｐ ｎ ｐ ｐ ｎ ｎ ｎ ｐ ｐ ｎΛ ｐ π- ｎ ｐ ｐ ｎ

Λ Λ d-quark s-quark s-quark

12C

6 ΛΛHe

p + Ξ- → Λ + Λ + 28MeV

Λ 5He

Λ r r ΛΛ

ΛΛ 6He

BΛ BΛΛ

M(Λ

M(ΛΛ

ΔBΛΛ = BΛΛ - 2BΛ

X - X - X - X

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2000年代までに 検出された事象数： 9 核種決定、質量再構成に成功した事象数：１

J-PARC E07 ： 過去10倍の統計量でダブルストレンジネス核を生成する実験

* Photographic emulsion gel 800kg→2.1t * Purity of K- beam 25%→85% * Automated Tracking in emulsion sheets *A = 6~17 LL hypernuclei : LL interaction, nuclear structure, LL-XN coupling. *X hypernuclei (X--16O, X--14N, X--12C ): XN interaction, LL- XN coupling.

First measurement of X-ray from X-atoms

Energy (keV) 100 200 300 400 500 600 700 800 Counts/2 keV 10 20 30 40 50 60

• Simulated for X--stopping for 104 events in the Emulsion
• Energy resolution for Ge : 2keV FWHM

Statistical accuracy of shift energies : Br(316 keV): 400 eV, Ag(370 keV): 200 eV

Ag(8,7)→(7,6) Case 1 370.45 0.28 0.15 Case 2 3.3 0.79 Br(7,6)→(6,5) Case 1 315.5 0.73 0.44 Case 2 5.5 1.74 Case 1: assuming potential shape to be the same as the nuclear density (tr potential ) Case 2: Nijmegen D model correcting to produce the potential depth of ~ 14 MeV.

Ξ- X-ray

107Ag

V Ag(n=8, l=7)→(n=7,l=6) r Ξ- 511 keV Ag(370 keV) 33 counts Br(316 keV) 18 counts Ge detector Hyperball-X

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KURAMA spectrometer for E07 KURAMA Magnet TOF wall Ge detector: Hyperball-X Diamond target SSD Emulsion stack

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“Emulsion mover” for J-PARC E07 SSD

K- beam 1.8GeV/c

Beam size： (sX, sY) = ~(10, 6)mm

Emulsion cassette

target

* Track density = 106/cm2 （Observable limit） * Sliding emulsion stack spill by spill * 6hours / stack

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SSD target

Emulsion cassette K- beam 1.8GeV/c

Beam size： (sX, sY) = ~(10, 6)mm

“Emulsion mover” for J-PARC E07

* Track density = 106/cm2 （Observable limit） * Sliding emulsion stack spill by spill * 6hours / stack

2017 2016 2015 2015 Oct. Commissioning run 1st physics run *Commissioning *18 modules 2nd physics run *Commissioning *100 modules 2015 May. Test experiment 2014 Emulsion sheet making -> in Kamioka mine Photographic Dev. Refreshing Photographic Dev. Refreshing Beam exposure Beam exposure

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• Jun. 30th, 2016

Analysis ~60%

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drying room

Tanks for photographic development The emulsion facility at Gifu University

pouring room

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Emulsion pouring Drying 28 degrees Celsius, 75% R.H., 2days Pouring melted nuclear emulsion 40 degrees Celsius, 3.1kg Flattened base-film by vacuum Pouring yard

!!Mock-up!!

Lead shield in Kamioka mine Cooling at 17 oC. 100µm

In a refrigerator in Gifu Univ. : ~400days In Kamioka mine. : ~400days

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Temp：25 ℃ R.H : 90 %

Refreshing

*Beam exposure *Photographic dev.

Refreshing: ・4days in Temp.:25 deg C, Humi.: 90 % ・humidification 2days + 4days + drying 2days ・ 4Ag + O2 + 2H2O -> 4Ag+ + 4OH-

Compton-elec. Tracks / (100mm)3 88.6 +- 3.4 48.1 +- 2.5

Refresh chamber capacity :100 sheets

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!!Mock-up!!

Emulsion sheet after photographic dev.

Photographic development

(Thin + 11Thick + Thin)*18stacks for the 1st physics run, 2016 Jun.- Aug.

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In washing

350*345mm2

1day preparation fix presoak, dev. washing drying next cycle -> preparation fix presoak, dev. timetable

*Momentum resolution : 1.4% *Missing mass resolution: ~14MeV/c2

reconstructed X- mass: 1319.5 +- 14.2 MeV/c2 with SSD X- tagging

*K+ yield : 1.03*105 events in 17.5 stacks in 1st physics run

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missing mass(CH2 target) X- mass peak in CH2 target run

p d p+ K+ p- K-

K+ tagging: momentum and missing mass measurement by KURAMA

X-candidates K+ dE (arb. unit) SSD dE

‘p’(K−,K+)X- event reconstruction

• data
• simulation

*Kinematics is consistent with simulation *Yield of X- stop event

1.6*103 events in 1st run 12.2*103 events in 2nd run

13.8*103 events (Total)

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X- K+

K- beam 1.8GeV/c

SSD

Target missing momentum

tanqx_missing_mom. – tanqx_Xtrack Stack

Alignment of SSD & Emulsion sheet

With pattern matching of p-bar beam tracks SSD 1st emulsion sheet （after development） Pattern matching 1st emulsion sheet （before development） SSD Emulsion p

• beam

SSD ~104/cm2

Y[mm] X[mm]

Pattern matching - dy:dx X-projection sx =21mm

Mod: 004-RightUpCorner

sy = 22mm

Y[mm] X[mm]

y-projection

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Beam direction

Track following : In Operation.

stop X-->Lp-Decay Found events

stop

10mm

X-->Lp-Decay Stop w/o fragment

• SSD-pl01 connection
• beam pattern matching for adjacent sheets
• image taking around stopping point

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Event reconstruction in emulsion sheet

* Track measurement: range, theta and phi * Initial state: bound system 12C or 14N or 16O and Ξ- * Selection possible decay modes. Conservation of charge, energy, momentum, Nbaryon, Nstrangeness etc. * PID with grain-density and “track boldness” * PID with Multiple Coulomb Scattering

P.R.L. 87, 212502 (2001)

2 3

Alpha decay event search by “Vertex-picker”

“Overall scanning” Finding vertex-like objects with image processing vertex-like objects

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Classification

*96% accuracy for 3 categories

Cross-tracks Beam Intl. Alpha decay

Density and Shrinkage measurement

212Po (8.785 MeV)

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E07実験はこれから収穫期に入る * Spectrometer system is well working * Successful establishment of Hybrid-Emulsion method for E07 *Emulsion analysis has just started. * Expected Xi stop event: 14*104

We will detect

NEW ONES

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pattern matching

pattern 1 pattern 2

…. …. * Put the both pattern on a temporary field. * Draw vectors for all the combination. peak detection in 2D histogram

X-

particles Physics process rstop sstop 2ry vertex Hadronic Int. Topology EnergyLoss->Stop InFlightDecay X-->Lp- (BR:99.9%) AtomicState->Capture InFlightDecay NoFragment sstop_Twin sstop_SingleHyper sstop_DoubleHyper WithFragment Through rstop+AugerElectron

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