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J-PARC E27 実験の概要

J-PARC E27 実験の概要. 岡村　敦史 ( Kyoto. Univ. ). for E27 Collaborations. Index. Introduction K - pp bound state E27 experiment Setup Preparation status Summary. K-pp bound state. Kbar N Isospin = 0 is strong attrective !  scattering experiment Xrays from Kaonic atom

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J-PARC E27 実験の概要

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  1. J-PARC E27実験の概要 岡村　敦史(Kyoto. Univ.) for E27 Collaborations ストレンジネス核物理 2010

  2. Index • Introduction • K-pp bound state • E27 experiment • Setup • Preparation status • Summary ストレンジネス核物理 2010

  3. K-pp bound state • Kbar N Isospin = 0 is strong attrective!  scattering experiment Xrays from Kaonic atom • Lambda(1405) = Kbar N system? • K-pp is the simplest Kaonic Nuclei. • Binding energy, Width theoritical prediction : 20-100,40-100 experimental result : exist? unconsistent B.E., Width • More measurements via various reaction are necessary!! J-PARC E15, E27 experiment Λ(1405) from PDG Mass : 1406.5 ± 4.0 MeV 　Width: 50 ± 2 MeV 　JP : ½- Unable to explain with 3 quark model 　Lighter than N*(1530) Meson baryon molecule state? 　(Chiral Unitary model) ストレンジネス核物理 2010

  4. E15 and E27 previous talk by Mr. T.Hiraiwa ストレンジネス核物理 2010

  5. J-PARC E27 Collaboration ,Y.Ichikawa ストレンジネス核物理 2010

  6. D(π+ K+)X reaction • ΛHypernuclei via (π+,K+) reaction at 1.06 GeV/c • Λ* production (th ~1.4 GeV/c ) • The possibility the production of K-pp bound state with deuteron target. (Λ* doorway) preriminaly Yamazaki & Akaishi, Phys. Rev. C76 (2007) 045201. π+ +“n” →　“Λ*”+ K+ “Λ*” + “p” → 　bound K-pp minor（~ 1.0%） → quasi free Λ* dominant Dr. Harada’s calculation sticking prababilityΛ with C12 target ~3%(mom transfer 500MeV/c) ストレンジネス核物理 2010

  7. D(π+ K+)X reaction SKS: Superconducting Kaon Spectrometer Δp=2MeV/c Missing mass π+ K+ n Λ* K-pp d p Δp/p=10^-4 Missing mass spectroscopy ΔM = 2.5MeV ストレンジネス核物理 2010

  8. Scattered K+ momentum with π beam@1.69GeV/c SKS Acceptance Bound Region D ( π+, K+ ) X Σ Λ • Λ,　Σ　＋ Ns X • Λ*,　Σ*　＋ Ns • Λπ,　Σπ　＋ Ns Σ*+ QF process is a large background. exclusive Measurement Λ* Σπ Σ*0 Λπ ストレンジネス核物理 2010

  9. Back ground suppression K-pp → Λ + p1, K-pp → Σ0 + p1, → p2 + π-（64%）→ Λ + γ, （100%） → p2 + π- Quasifree process π+ +d → Λ* + K+ + p1s, Λ*→ Σ + π, Σ+→ p2+π0 P1s< 250MeV/c Confirm K-pp by tagging the two high-momentum protons ストレンジネス核物理 2010

  10. Range Counter (Y.Ichikawa’s talk) • Range counter = particle ID by beta vs range • Effective selection of fast (300 ~ 700 MeV/c) proton 10mm 50mm 20mm 20mm Red : proton Black : π- 10mm Pion Proton ストレンジネス核物理 2010

  11. angular distribution of 2proton （>300MeV/c) from K-pp 2 proton tagging at Forward (33 ~ 93 degree) K-pp → Λ + p, → p + π- K-pp → Σ0 + p → Λ + γ, proton1 theta_Lab → p + π- proton1 theta_Lab proton2 theta_Lab proton2 theta_Lab ストレンジネス核物理 2010

  12. Range counter for E27~ detect the fast 2 proton ~ ＳＫＳ • Detection coverage is 33°~93° • 14% acceptance • Yeild Estimation • π+ intensity = 5M/spil • dσ/dΩ=60μb/sr, ΔΩ=100 msr • Deuteron = 1.4 g/cm2 • ηdecay, ηtrack = 0.5, 0.5 Λ(1405) production rate = 6.0x104/day • Λ* trapping probability = 1% • K-pp non-mesonic decay branch = 20% • Λ+ Σ0decay modes = 2/3 • Λ to emit proton = 2/3 • Two-proton tagging efficiency = 14% K-pp event rate =~8.0/day K+ 500 33° p p Target 93° ~300events/40days π+ ストレンジネス核物理 2010 BH2

  13. The differential cross section for π-p→Λ(1405)K0 • Λ（1405）production cross section in the very forward direction is 5μb/sr （CM）. →　60μb/sr（Lab） D.W. Thomas et al., Nucl. Phys. B56 (1973) 15. ストレンジネス核物理 2010 13

  14. Range Counters Status (Y.Ichikawa’s talk) • Range counter • Test experiment performed (Dec 2009) • @K1.8 scattered particle • Configuration determined • test experiment (Oct 2010) • Analysis method optimization • construction 1/3 of all Range Counters were finished including Support structure. • The construction will be finished at Feb. 2011. ストレンジネス核物理 2010

  15. inclusive measurement with 1M Pion 1M pi /spill *(86400sec/6sec) *1.4g/cm2 /2 *NA *334.3e-30 cm2 *0.5(K decay) *0.5 (eff.) ~ 0.5M events!! uppper limit of Yield of K-pp • feasibility of 2 proton Tag MC spectrum FINUDA, DISTO K-pp 50 ev/ day ストレンジネス核物理 2010

  16. Future Plan • deuteron  He3 • K-pp  K-ppp • satellite state • 2proton tagging? ストレンジネス核物理 2010

  17. Summary • J-PARC E27 experiment • search for a K-pp bound state using D(π,K) reaction • measure the missing mass K-pp states • 2 proton tagging • The preparation is well under way. • RC construction by Feb. 2011 • Inclusive measurement • Upper limit • Thank you for your Attention! ストレンジネス核物理 2010

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