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Missing mass spectroscopy of hypernuclei at J-PARC (J-PARC E70)

Reimei workshop @J-PARC. Missing mass spectroscopy of hypernuclei at J-PARC (J-PARC E70). Kyoto University Toshiyuki Gogami January 10, 2019. J-PARC E05 (2015). Contents. Motivation Ξ hypernuclei in the past E05 with SKS E70 with S-2S. J-PARC E70 collaboration.

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Missing mass spectroscopy of hypernuclei at J-PARC (J-PARC E70)

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  1. Reimei workshop @J-PARC Missing mass spectroscopy of hypernuclei at J-PARC (J-PARC E70) Kyoto University Toshiyuki Gogami January 10, 2019 J-PARC E05 (2015)

  2. Contents • Motivation • Ξ hypernuclei in the past • E05 with SKS • E70 with S-2S

  3. J-PARC E70 collaboration • T. Nagae (Spokesperson), T. Gogami, S. Kanatsuki, H. Ekawa, T. Nanamura, M. Naruki (Kyoto Univ.) • H. Fujioka (Tokyo Institute of Technology) • S. Hasegawa, K. Hosomi, Y. Ichikawa, K. Imai, H. Sako, S. Sato, K. Tanida, J. Yoshida, (JAEA) • S.H. Hayakawa, M. Nakagawa, Y. Nakada, T. Akaishi, A. Sakaguchi (Osaka Univ.) • Y. Akazawa, M. Fujita, R. Honda, K. Miwa, H. Kanauchi, A. Koshikawa, H. Tamura, S.N. Nakamura, M. Kaneta, S. Nagao, Y. Toyama, K. Itabashi, (Tohoku Univ.) • K. Aoki, E. Hirose, H. Takahashi, T. Takahashi, M. Ukai, T.O. Yamamoto, (KEK) • J.K, Ahn, S.H. Kim, H.M. Yang, K.Y. Roh, (Korea Univ.) • E. Botta, A. Feliciello, (INFN Torino) • M. Agnello (Politecnicodi Torino) • P. Evtoukhovitch, Z. Tsamalaidze, (JINR) • J.Y Lee, T. Moon (Seoul National University) • T. Hasegawa (Kitasato University) • K. Shirotori, M. Yosoi, ( RCNP) • D. Shoukavy, ( B.I. Stepanov Institute of Physics) • L. Tang (Hampton) 54 from 15 affiliations

  4. E70: Physics Motivations • ΞN Interaction : Last key information in Baryon(8)-Baryon(8) interactions in SU(3)F. • Almost no experimental information • Weakly attractive (?) In FSS2 • Two body Ξ-n bound state (?) in ESC models • Recent HAL QCD potentials suggest weak attractions and small coupling between Ξ-p-ΛΛ.

  5. YN Interactions YN/YY NN • Very limited scat. exp. data • Hypernucler structure • 30 MeV • Λ-N: SS, SO, tensor • : Repulsive + Large isospin dependence Rich data of scat. exp.  Realistic nucl. force model Strong constraints on the BB Int. Models

  6. Role of strangeness in high-density hadronic matters H. Togashiet al., Phys. Rev. C 93, 035808 (2016) • Hyperon appearance → Softening of EOS • The EOS cannot hold 2M⦿ (Hyperon puzzle) • YNN three-body force would be a key • Not only Λ but other strangeness baryons • Terrestrial experiments • BB interaction with strangeness degree of freedom • Astronomical observation • Binary NS mergers observed B. P. Abbott et al., Phys. Rev. Lett. 119, 161101 (2017).

  7. Experimental Information on Ξ-hypernuclei KISO event: • 1.03 or 3.87 MeV ±Γ/2 • Well beyond the atomic binding of 0.17 MeV K. Nakazawa et al., PTEP (2015) 033D02

  8. BNL E885: HY spectroscopy with the (K-,K+) reaction P.Khaustovet al., PRC61 (2000) 054603 Diamond Target 12C(K-,K+)12ΞBe FWHM 14 MeV BNL E885 K+ 0.8 – 1.40 GeV/c K- 1.8 GeV/c () () (-20 < < 0 MeV) MeV

  9. (missing mass spectroscopy at J-PARC

  10. J-PARC E05 at K1.8 (w/ SKS) in 2015

  11. J-PARC E05 experiment (1) p π+ K+ • 12C(K-,K+) at 1.8 GeV/c • 26-Oct-2015 ~ 19-Nov-2015 • K- intensity : 6x105 K- / spill (5.52 seconds cycle) @ 39 kW • 9.36 g/cm2natC; 10 days • 9.54 g/cm2 CH2; 2 days Mass squared m2 (GeV/c2)2 T. Nagae et al., PoS (INPC2016)038

  12. J-PARC E05 experiment (2) • The system worked as we expected (FWHM = 5.4 MeV Expectation of 5.1 MeV) • No experiments exist better than this so far • Elementary process cross section is maximum at GeV/c (new data!) 5.4 MeV FWHM

  13. J-PARC E05 experiment (3) Preliminary Preliminary • Significant events ~50 in the bound region over a flat background events of ~10 events (up to -40 MeV). • The spectrum shape near the threshold is consistent with the BNL E885 data. • The data is in cautious analysis and will be finalized soon. ~50 counts in bound region assuming flat b.g.

  14. E70 Experimental Setup 1.37 GeV/c

  15. S-2S magnet major parameters

  16. Field comparison between measurements and calculations distribution Meas. Residual between meas. and calc. • Near pole: 1.3 mT • Other area: 0.4 mT Calc. (FWHM) After corr. SIMULATION: 1.375 GeV/, m He bag installed in particle path Before corr.

  17. Tracking and mom. analysis 1. Q1 Q2 D TOSCA calc. for each magnet Magnetic field meas. for each magnet (Optimization for TOSCA model parameters) 2. TOSCA calculation of Q1 Q1+Q2+D TOSCA calc. for all magnets (Magnetic field map) 3. Ξ production will be used for calibration Q1+Q2+D • Monte Carlo simulation (Geant4) • Real data analysis • (tracking  mom. analysis w/ Runge-Kutta)

  18. Momentum acceptanceand momentum resolution • Central momentum at 1.37 GeV/c • K-p→pK- ; high-momentum proton : out of acceptance SIMULATION SIMULATION

  19. Active Target Direct measurement of the energy loss (including straggling)  Better energy resolution in resulting missing mass • 1 set = xx’yy’ = 100 fibers • 9 sets in total  900 fibers (both edge reading: 1800 ch) • Scintillating fiber (Saint-Gobain BFC-10; φ3, single clad) + MPPC (S13360-3075PE, Hamamatsu; 3 mm square, 75 μm pitch, opening 82%) + VME EASIROC 5 cm 10 cm 10 cm active volume = 84%

  20. AFT test at RCNP • June, December in 2016 • Grand RIDEN @RCNP • 1/37000 • 0.5—3.8 MeV using proton at 65 and 295 MeV 0.7 MeV @ 1.4 GeV/c  10%

  21. AFT simulation (Geant4) Elementary process Ξ hypernuclear production Energy loss information only for K- and K+ are needed  Track pattern analysis is necessary

  22. Beta distribution of particles in AFT Beta difference Energy loss difference  It helps for identification of kaon energy loss

  23. Simulated MM before and after AFT correction FWHM = 2 MeV

  24. Overall Energy Resolution (MeV)

  25. Overall Energy Resolution (MeV) Could be improved

  26. Yield Estimation from E05 run

  27. Expected spectra ESC08 T. Motoba and S. Sugimoto, NPA835 (2010) 223-230 E05 ESC08 E70 w/ AFT In the simulation, the natural width was not taken into account.

  28. preparation status • Spectrometer: 100% (ready to install) • Tracking devices: 70% • Commissioning • Cable preparation etc. • Scintillation detectors: 90% • Cherenkov detectors*): 90% • Fiber target: 20% • Sub system study (-2019 summer) • Construction (-2019 November) *) T.Gogami et al., NIMA 817 (2016) 70—84

  29. Summary • Ξ-N interaction information is crucial for understanding B-B interactions in SU(3)F. • BNL E885, Kiso event, and E05 pilot run suggest attraction of the Ξ-N interaction. • S-2S will reveal the spectroscopic information of Ξ hypernuclei with 2 MeV (FWHM) resolution. • Definite answer of Ξ biding energy will be obtained.

  30. Backup

  31. Expected spectra ESC08 E70 T. Motoba and S. Sugimoto, NPA835 (2010) 223-230 w/o AFT ESC08 E70 w/ AFT In the simulation, the natural width was not taken into account.

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