Studies for charge symmetry breaking effect in hypernuclei with nuclear emulsion

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1 Studies for charge symmetry breaking effect in hypernuclei with nuclear emulsion 〇 M. Yoshimoto 1, J. Yoshida 2, K. Nakazawa 1 and J-PARC E07 Collaboration 1. Gifu University 2. Advanced Science Research Center, JAEA Revised in slide no. 5, 23 and June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 1

2 Outlines 1. Nuclear emulsion history detector specification 2. Past experiments 3. J-PARC E07 experiment A hypernucleus 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 2

3 Very Brief History of nuclear emulsion 1910 : S. Kinoshita Observation of alpha particle with photographic emulsion 1947: C. F. Pawell et al. Discovery of π-meson in cosmic ray. 1949: G. Rochester et al. Discovery of K + π + π + π - with nuclear emulsion 1955: E. Segre & O. Chamberlain Detection of antiprotons. 1971: K. Niu et al. Discovery of open charm meson with cosmic ray. 1977: E531 experiment First Neutrino oscillation experiment. 1985: WA75 Detection of open bottom meson with accelerator 1988: KEK-PS E176 exp. Search for double hypernuclei and H dibaryon with counter-emulsion hybrid method 1999-: KEK-PS E373 exp. Search for double hypernuclei with the hybrid method 2000 : DONUT experiment Direct observation of τ neutrino : OPERA experiment Discovery of τ neutrino appearance 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 3

Discovery of π-meson in cosmic ray (1947) C. F. Pawell et al. Nature 159 186 (1947) H.

4 Discovery of π-meson in cosmic ray (1947) C. F. Pawell et al. Nature (1947) H. Yukawa, Nobel prize in 1949 C. F. Pawell, Nobel prize in 1950 π μ 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 4

5 Detection of antiprotons in nuclear emulsion Antiproton E. Segre & O. Chamberlain Phys. Rev (1955) 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 5

Structure of nuclear emulsion plate Charged particles Detector elements = Silver halide crystals 10 14 /cm 3 200 nm The highest spatial resolution as tracking detector Performance of the crystals

6 Structure of nuclear emulsion plate Charged particles Detector elements = Silver halide crystals /cm nm The highest spatial resolution as tracking detector Performance of the crystals Average size Size variance Crystal density Quantum efficiency Gelatin binder Diameter: 200±16 nm Density: /cm 3 Efficiency: 5 10 % for MIP Image with electronic microscope. developed by Fujifilm. 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 6

7 Charged particles h e- h e- h h e- Ag n Ag n e- he- e- h e- h e- h The ionization following the passage of the charged particles generates electron-hole pairs in the silver bromide crystal. The electron reduces silver ions and makes a latent image (silver atoms). Ag + + e - Ag Ag + Ag + + e - Ag 2 Ag n-1 + Ag + + e - Ag n Energy level of AgBr 3.5 ev 2.6 ev e - h Valence band trap 0eV line Conduction band Ag + + e - Ag 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. C. W. Peterson Phys. Rev (1966) 7

Ag Development Chemical development: Supply silver

to an observable size Ag Fixing: Remove unwanted AgBr

Fixing AgBr silver cluster = grain 25 June 2018

8 Ag Development Chemical development: Supply silver with reducing agent Ag + + e - Ag Grow latent images to an observable size Ag Fixing: Remove unwanted AgBr 2 Na 2 S 2 O 3 + AgBr Na 3 [Ag(S 2 O 3 ) 2 ] + NaBr Fixing AgBr silver cluster = grain 25 June 2018 HYP2018 in Portsmouth Image Virginia, U.S.A. with optical microscope. 8

9 Very Brief History of nuclear emulsion 1910 : S. Kinoshita Observation of alpha particle with photographic emulsion 1947: C. F. Pawell et al. Discovery of π-meson in cosmic ray. 1949: G. Rochester et al. Discovery of K + π + π + π - with nuclear emulsion 1955: E. Segre & O. Chamberlain Detection of antiprotons. 1971: K. Niu et al. Discovery of open charm meson with cosmic ray. 1977: E531 experiment First Neutrino oscillation experiment. 1985: WA75 Detection of open bottom meson with accelerator 1988: KEK-PS E176 exp. Search for double hypernuclei and H dibaryon with counter-emulsion hybrid method 1999-: KEK-PS E373 exp. Search for double hypernuclei with the hybrid method 2000 : DONUT experiment Direct observation of τ neutrino : OPERA experiment Discovery of τ neutrino appearance Hybrid method with counter Semi-automated stage Fully automated read-out system with a speed beyond human 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 9

10 How to determine the energy and identify the particles 1. Energy-loss: Bethe-Bloch equation Range-Energy relation Grain linear density measurement 2. Multiple coulomb scattering PDG June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 10

11 Mirror hypernuclei Normal nuclei 4 He Λ 4 H Hypernuclei Λ 4 He n n p p n n Λ p n p Λ p Λ 4 H π + 4 He π + 1 H + 3 H π + 2 H + 2 H Λ 4 He π + 1 H + 3 He π + 1 H + 1 H + 2 H Mesonic decays w/o neutron Mirror hypernuclei B Λ = B Λ Λ 4 He B Λ Λ 4 H 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 11

12 Measurement of B Λ B Λ = Q 0 Q Q 0 = M Λ + M Z A 1 mi core decay products Total visible energy in emulsion 1. Range measurement error 2. Emulsion density and shrinkage factor measurement error 3. Range straggling Emulsion can measure B Λ of various nuclides in the same detector. Thus, the other systematic errors will be canceled. 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 12

13 B Λ past results in nuclear emulsion [3] [3] [2] [4] [2] [2] Table: D.H. Davis Nucl. Phys. A754 3 (2005) M. Juric, et al., NuclPhysB52_1 (1973) [2] T. Cantwell, et al. NuclPhysA236_445 (1974) [3] J. Pniewski, et al., NuclPhysA443_685 (1985) [4] D. Dłuzewski, et al., NuclPhysA484_520 (1988) 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 13

14 B Λ past results in nuclear emulsion 279 events 1 VS 155 events 1 68 events 1 VS 787 events 1 4 events 3 VS 13 events 3 10 events 1 VS 3 events 2 6 events 4 VS 87 events 1 The systematics error is dominant. The statistical error is dominant. Table: D.H. Davis Nucl. Phys. A754 3 (2005) M. Juric, et al., NuclPhysB52_1 (1973) [2] T. Cantwell, et al. NuclPhysA236_445 (1974) [3] J. Pniewski, et al., NuclPhysA443_685 (1985) [4] D. Dłuzewski, et al., NuclPhysA484_520 (1988) If we get an order of magnitude higher events and apply the latest range and emulsion calibration method, we will discuss B Λ of the multiplet pairs up to 12 C with high accuracy. 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 14

15 Beam exposure J-PARC E07 in 2016 and 2017 Cover with SSD and Ge detector Emulsion mover K - Diamond target ( 12 C) K + K GeV/c Ξ - SSD Thin Thick Thick Thin 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 15

Chemical development for E07 in Gifu Univ.

Main talks on the E07 experiment will be

16 Chemical development for E07 in Gifu Univ. 350mm 345mm Thickness ~1mm Presoak 5 deg. Dev. 5 deg. Presoak 5 deg. Fix 5deg. Stop 5deg. Main talks on the E07 experiment will be given by J. Yoshida tomorrow. Dev. 5 deg. Dev. 20deg. 60 plates/cycle (total 1298 plates) ~5 days/cycle from presoak to fix 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 16

J-PARC E07 Nuclear Emulsion Elemental composition Element Atomic % H 39.6 C 20.6 N 5.9 O 11.3 Ag 11.2 Br 11.1 Thick emulsion plate after chemical development 34.5 cm x 35.

17 J-PARC E07 Nuclear Emulsion Elemental composition Element Atomic % H 39.6 C 20.6 N 5.9 O 11.3 Ag 11.2 Br 11.1 Thick emulsion plate after chemical development 34.5 cm x 35.0 cm Density: g/cm 3 Shrinkage factor: Requires calibration using alpha decay (Z=2) and muon (Z=1) from π + decay 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 17

18 Estimation of single hypernuclei All events = Overall method Direct process K - beam: ~10 10 in total 3 : 1 preliminary via Ξ - atom 2 : 1 n(k -, K 0 ) Ξ - p(k -, K + ) Ξ - 2 : 1 un-triggered triggered Ξ - Hybrid method Hybrid Overall # of events 1 ~30 Area to analyze 1 ~1000 via Ξ - atom 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 18

Vertex Picker Fully automated microscopic stage High resolution CMOS 2048*1088 pixels High frame rate 300fps Wide FOV x20 dry lens (NA0.35) 565 300 μm 2 Piezoelectric drive Stroke 200 micron Period 1.

19 Vertex Picker Fully automated microscopic stage High resolution CMOS 2048*1088 pixels High frame rate 300fps Wide FOV x20 dry lens (NA0.35) μm 2 Piezoelectric drive Stroke 200 micron Period 1.3 Hz (current) Picture 32picts /cycle Camera/processor For hybrid method For vertex picker Frame rate 60 fps x5 300 fps resolution Field of view(μm 2 ) x Image processing CPU CPU & GPU 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 19

20 Vertex Picker Search all region for vertex like event. developed by J. Yoshida NIM A (2017) multi vertexes = candidates Spatial resolution δx = 0.9 um, δz = 8 um High resolution microscopy Analyze in detail. Spatial resolution δx = 0.36 um, δz = 1.4 um Accumulated image 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 20

21 Result of vertex picker Total 1,718,515 vertex candidates # of candidates / (2mm) 2 An E07 emulsion plate 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 21

22 Detail analysis Vertex picker system vertex candidates 150,334 events 2-vertexes cand. 282 events others Analyzed region 100 mm 100 mm 2-vertexes 248 events others 34 events w/ thin track* 107 events w/o thin track 141 events High resolution microscopy * The thin tracks are not identified as π-meson. 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 22 8

23 Estimation with all the E07 emulsion plates ~1.7G vertex candidates ~3M two vertexes ~1M two vertexes w/ thin track Almost all events are single vertex or fake events Two third will be w/o thin track It would be to obtain an order of magnitude more events approximately. cf. 27K mesonic decay Nuclear Physics B52 (1973) June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 23

Mesonic decay of single hypernuclear event #2 p - Λ 4 H #1 #3 Track Range (μm) Theta θ (deg.) Phi φ (deg) #1 5.3 ± 0.5 18.9 ± 2.1 58.2 ± 1.3 #2 29.0 ± 1.7 132.3 ± 1.8 237.3 ± 1.9 #3 12520 ± 20 125.

24 Mesonic decay of single hypernuclear event #2 p - Λ 4 H #1 #3 Track Range (μm) Theta θ (deg.) Phi φ (deg) #1 5.3 ± ± ± 1.3 # ± ± ± 1.9 # ± ± ± 3.3 This decay is only allowed by kinematic analysis. Λ 4 H π + d + d Invariant mass [MeV/c 2 ] Measured ±0.3* Nuclear DB ±0.04 *Calibration was not finished. Not confirmed. Analyzed by May Sweet 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 24

25 Summary and prospects There are many uncertainties in the past results of the emulsion experiments, and some issues can be solved by increasing events. Emulsions can discuss various single hypernuclei in the same detector with sub-mev accuracy. Development and analysis of reading the E07 emulsion plates is ongoing. According to the estimate, 1,000K two vertexes w/ thin track will be acquired Hybrid method Development Overall method We plan to start full-scale analysis using the overall method with vertex picker from The new results of B Λ will be released in a few years. 25 June 2018 HYP2018 in Portsmouth Virginia, U.S.A. 25

J-PARC E07 Ξ - Junya Yoshida (Advanced Science Research Center, JAEA) On behalf of J-PARC E07 Collaboration K + K - X -

J-PARC E07 Ξ - Junya Yoshida (Advanced Science Research Center, JAEA) On behalf of J-PARC E07 Collaboration K + K - X - J-PARC E07 Systematic study of double strangeness nuclei with Hybrid emulsion method LL hypernucleus K - 1.8GeV/c Target SSD X - K + nλ p p Λ n X hypernucleus n p p Ξ - n Ge detector X-ray X-ray from X