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Spectroscopic study of Lambda(1405) via the (K-,n)reaction on deuteron.

Spectroscopic study of Lambda(1405) via the (K-,n)reaction on deuteron. Baryons’10@Osaka.Univ 2010/12/10 Shun Enomoto RCNP,Osaka.University For the J-PARC E31 collaboration. Contents. Introduction - Λ (1405) -(K - ,n) reaction on deuteron. J-PARC E31 experiments -Experimental method

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Spectroscopic study of Lambda(1405) via the (K-,n)reaction on deuteron.

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  1. Spectroscopic study of Lambda(1405) via the (K-,n)reaction on deuteron. Baryons’10@Osaka.Univ 2010/12/10 Shun Enomoto RCNP,Osaka.University For the J-PARC E31 collaboration

  2. Contents • Introduction -Λ(1405) -(K-,n) reaction on deuteron. • J-PARC E31 experiments -Experimental method (identify I=0 state in KbarN->πΣprocess) • Preparation status -Development detector • Summary

  3. Introduction

  4. Λ(1405) I=1 I=0 Λ(1520),3/2- KN(1432) • 3quark?5quark? • KbarN 1406.5MeV/c2[one pole?] Deeply bound KbarN state. Y.Akaishi & T.Yamazaki, Phys. Rev. C65(2002) 04405. Y.Akaishi & T.Yamazaki, Phys. Lett. B535 (2002) 70 1420MeV/c2[two pole?] Chiral Unitary Model predicted. T. Hyodo, D. Jido, and A. Hosaka, Phys. Rev. Lett. 97, 192002(2006); T. Hyodo, D. Jido and A. Hosaka, Phys. Rev. D75, 034002(2007). T. Hyodo and A. Weise, Phys. Rev. C77, 035204(2008) Λ(1405),1/2- -27MeV ∑*(1385),3/2+ ∑(1192),1/2+ Λ(1116),1/2+ A spectroscopic study of Λ(1405) directly coupled to KbarN is desired. KbarN scattering below KbarNthrethold. →d(K-,n) reaction

  5. the(K-,n) reaction on Deuteron. K Motivation ・To clarify whether Λ(1405) is KbarN resonant state. π 2H Y* ∑ KN :1432MeV pn 1405MeV/c2? n t 1420MeV/c2? K- J.Yamagata-Sekihara, T.Sekihara,andD.Jido, paper in preparation ? S-wave Σ*(1385) P-wave I=1 I=0,1 Purely I=0 Λ*(1405) • Λ(1405) and BG(NR/∑*) • S-wave,I=0 　→Λ*(1405)→π0∑0,π-∑+ ,π+∑- • S-wave,I=1　 →non-resonant(NR) • P-wave,I=1 →∑*(1385) → π0Λ,π-∑+ ,π+∑- Non-resonant I=1 Possible ID of I=0 in KbarN->π∑ Possible decomposition of I=0 amplitude. Y*(mass)

  6. J-PARC E31 experiments

  7. J-PARC E31 Collaboration • S. Ajimura1, G. Beer2, H. Bhang3, M.Bragadireanu8,P. Buehler4, L. Busso5,6, M. Cargnelli4, S. Choi3, C. Curceanu8, S. Enomoto1, D. Faso5, H. Fujioka13, Y. Fujiwara12, T. Fukuda11, C. Guaraldo8, T. Hashimoto12,R. Hayano12, T. Hiraiwa 13, M. Iio9,K. Inoue1, N. Ishibashi17, T. Ishikawa12, S. Ishimoto14, T. Ishiwatari4, K. Itahashi9, M. Iwai14, M. Iwasaki9,10,S. Kawasaki1, P. Kienle15, H. Kou10,J. Marton4, Y. Matsuda12, Y. Mizoi10, O. Morra5, T. Nagae13, H. Noumi 1, H. Ohnishi9, S. Okada8, H. Outa9,Y. Sada13, A. Sakaguchi17, F. Sakuma9, M. Sato12, M. Sekimoto14,H. Shi12, D. Sirghi8, F. Sirghi8, S. Suzuki14, T. Suzuki12, H. Tatsuno12, M. Tokuda10, D. Tomono9, A. Toyoda14, K. Tsukada9, E. Widmann4, T. Yamazaki9,12, K. Yoshida17, H. Yim3, B. Wünschek4, J. Zmeskal4 • 1. Research Center for Nuclear Physics, Osaka University, Japan • 2. University of Victoria, Canada, 3. Seoul National University, South Korea • 4. Stefan Meyer Institut fur subatomarePhysik, Austria, • 5. INFN Sezionedi Torino, Italy , 6.Universita’ di Torino, Italy • 8. LaboratoriNazionalidiFrascatidell’INFN, Italy • 9. RIKEN, Japan, 10. Tokyo Institute of Technology, Japan • 11. Osaka Electro-Communication University, Japan, 12. University of Tokyo, Japan • 13. Kyoto University, Japan, 14. High Energy Accelerator Research Organization (KEK), Japan • 15. TechnischeUniversitatMunchen, Germany, 16. INAF-IFSI, Sezionedi Torino, Italy • 17. Osaka University, Japan

  8. J-PARC E31 Experiments 3He(K-,n)”Kpp” reaction J-PARC E15@J-PARC K1.8BR • Spectroscopic study of Hyperon Resonances below KbarNthrethold via the (K－,n) reaction on Deuteron. Decay Particle Detector (CDS) n ~1.3GeV/c Neutron counter (TOF) ΔT~150ps Target(D) K－ 1.0GeV/c 15m Λ(1405) ・To measure Λ* mass spectra by Missing Mass . Σ-π+,Σ+π-→I=0 Λ* I=1 NR I=1 Σ* Σ0π0 →I=0 Λ* Λπ0 →NR or Σ* ・σMM~9MeV/c2 at PK- = 1.0GeV/c ・To Identify Λ* decay mode by CDS

  9. J-PARC K1.8BR K-beam beam spectrometer 15m Liq.D target neutron counter Rearrange 2010/10/25 Decay particle detector(CDS)

  10. Identification of Λ* decay mode. case1: π+∑-and π-∑+ Λ(1405)→　 ∑+π-→ (nπ+)π- 　　 　　　 ∑-π+→ (nπ-)π+ case2: π0∑0 and Λπ0(NR/∑*) Λ(1405)　　 →∑0π0→Λγπ0→(pπ-)γπ0 NR/Σ(1385) →Λπ0 →pπ-π0

  11. Detection of the Λ* ->∑-π+ and ∑+π-modes Λ(1405)→　∑+π-→ (nπ+ )π-or ∑-π+→ (nπ-)π+ Solenoid magnet CDH CDC(Drift chamber) 0.1~0.3GeV/c π+ 0.1~0.2GeV/c π- 0.5T ZVC K-=1.0GeV/c ∑+ target Λ(1405) n(~1.3GeV/c) n The J-PARC E15 setup is quite suitable to detect π.

  12. Identification of the decay modes:Λ* ->∑-π+ or ∑+π- KbarN Σ+π- Σ-π+ ② ① ① Γ(Λ*→∑+π-)/Γ(Λ*→∑-π+)～1 (Σ-π+): MM(Σ-mass) (∑+π-) MM(mass) MissingMass2(MeV/c2)2 Σ+π- ×103 Σ-π+ missID(Σ+π-)=(∑-π+[①])/(Σ+π-[②])

  13. Λ(1405)→∑0 π0→Λγπ0→ (p π-)γπ0 NR/∑(1385)→Λπ0→(pπ-)π0 Λ*→∑0π0 ,(∑*→Λπ0) Solenoid magnet CDH π-:~200MeV/c CDC(Drift chamber) Backward Proton detector(BPD) & chamber(BPC) P:~500MeV/c ZVC ∑0 n(~1.3GeV/c) target K-=1.0Gev/c π0 BPD measures to momentum of proton by TOF methods.

  14. ID & Efficiency for Λ*->π0Σ0 Λ(1405)→∑0 π0→Λγπ0→(p π-)γπ0 NR/∑(1385)→Λπ0→pπ-π0 Γ(Λ*)/Γ(Σ*)～1 Λ*->∑0π0 P:fourth momentum Proton Detector Resolution(σ) Σ*->Λπ0(π0mass) efficiency Λ*->π0Σ0 ([π0+γ]mass) ① ② MM2(MeV/c2)2 Σ*->Λπ0contamination ×103 Hyperon X mass[MeV/c2] Λπ0(contamination)=(Λπ[②])/(Λπ)

  15. Preparation status

  16. Backward Proton Detector(BPD) • TOF for proton ->Scintillation Hodoscopes with MPPC. Beam test: Time Resolution(BPD-T0) σ~250ps (T0-PD) MPPC-50μm σ=246.4ps Prototype(BPD): 5mm2×400mm Scintillator with MPPC-50μm Meantime[ns]

  17. Backward Proton Chamber(BPC) • Vertex Detector for Λ->pπ- • -> determine the reactionpoint(z vertex) • for better Pn measurement in Λ*-> π0Σ0 ASD base 168mm 117mm • Wire gap 3.6mm(xx’yy’xx’yy’:8layers) • Active area φ111.6mm(readout:15ch(1layer)) • Outside diameter φ=168mm(z-TPC inside diameter φ=170mm)

  18. Summary • We propose to study Λ(1405) hyperon resonance via the d(K-,n) reaction. →To investigate Λ(1405) in the coupled channel KbarN->πΣ system. • We found that the J-PARC E15 setup has sufficient detection efficiency to identify Λ*->π+Σ- and Λ*->π-Σ+ clearly. • We introduce BPD & BPC to identify Λ*->π0Σ0 clearly. • Thank you

  19. Back up

  20. Future plan ~2011:Summer;BPC & BPC will be ready 2011:Autumn~;Engineering run start? 201? ;E31 experiment start?

  21. Yield estimation (E31 experiment) R:reconstruction(0.24)A:analysis(0.9)

  22. Simple the reaction mechanism. ->d(K-,n)π+Σ- at PK-=800MeV/c 4deg 10deg KN n K- D D(K-,n)X(1400) P_KN 0deg S-wave KbarN scattering is dominant at θn =0 degree.

  23. Contamination(Mis-identification) ~a few%

  24. Λ(1405)/Σ(1385)_1 • Clebsch-Gordancoeficients • Σ(1385)[I=1] can not decay π0Σ0 .

  25. Detection of the Λ* ->∑-π+ and ∑+π-modes Λ(1405)→　∑+π-→ (nπ+ )π-or ∑-π+→ (nπ-)π+ Solenoid magnet CDH π- Σ+π- Σ-π+ CDC(Drift chamber) 0.1~0.3GeV/c π+ 0.1~0.2GeV/c π- 0.5T momentum ZVC angle K-=1.0GeV/c ∑+ target Λ(1405) n(~1.3GeV/c) n The J-PARC E15 setup is quite suitable to detect π.

  26. Λ(1405)→∑0 π0→Λγπ0→ (p π-)γπ0 NR/∑(1385)→Λπ0→(pπ-)π0 Λ*→∑0π0 ,(∑*→Λπ0) Solenoid magnet Σ0π0 proton Λπ0 CDH π-:~200MeV/c CDC(Drift chamber) Backward Proton detector(BPD) & chamber(BPC) momentum angle P:~500MeV/c ZVC ∑0 n(~1.3GeV/c) target K-=1.0Gev/c π0 BPD measure s to momentum of proton TOF methods.

  27. Decay mode[Λ(1405)/Σ(1385)] • Λ(1405)→π-Σ+→π- (pπ0) [51.57%] or π-(nπ+) [48.31%] π+Σ-→π+(nπ-)[99.84%] π0Σ0→π0Λγ→π0(nπ0)[35.8%] or π0(pπ-)γ[63.9%] • Σ(1385)→πΛ[87.0%] →πΣ[11.7%]

  28. Cylindrical Detector System • A newly developed system for invariant mass study • Expected mass resolution: • - s ~ 3.0 MeV/c2 for L • - s ~ 13 MeV/c2 for K-pp • ( scdc = 200 mm / Field : 0.5 T)

  29. Neutron counter E549 neutron counter 3.2 m rearrange 1.5 m support frame for E15 • 20 x 5 x 150 cm3 Plastic Scintillator • Configuration : 16 (wide) x 7 (depth) • Surface area : 3.2m x 1.5m • missing mass resolution for K-pps = 9.2 MeV/c2 (Pn=1.3 GeV/c, sTOF=150 ps)

  30. D(K-,n)π+∑-(PK=800MeV/c) Λ* J.Yamagata-Sekihara, T.Sekihara,andD.Jido, paper in preparation

  31. 中性子の運動量 4deg 10deg 0deg D(K-,n)X(1400) KNの運動量 L=0,s-waveの反応断面積が大きい

  32. the(K-,n) reaction on Deuteron. K Motivation ・To clarify whether Λ(1405) is KbarN resonant state. KbarN scattering below KbarNthrethold. →d(K-,n)Λ* reaction is KbarN direct reacion. π 2H Y* ∑ KN :1432MeV pn n 1420MeV/c2? t 1405MeV/c2? K- S-wave Σ*(1385) P-wave I=0 I=0,1 ? Λ*(1405) Non-resonant I=1 Y*(mass)

  33. the(K-,n) reaction on Deuteron. S-wave KbarN scattering is dominant at θn = 0 degree Possible ID of I=0 in KbarN->πΣ • S-wave,I=0 　→Λ*(1405)→π0∑0,π∑+ ,π+∑- • S-wave,I=1　 →non-resonant(NR) • P-wave,I=1 →∑*(1385) → π0Λ,π-∑+ ,π+∑- Λ* Σ* D(K-,n)π+∑- at PK=800MeV/c Enhancement of Λ* production at θn=0 BackGround from Σ* will be reduced J.Yamagata-Sekihara, T.Sekihara,andD.Jido, paper in preparation Purely I=0 Possible decomposition of I=0 amplitude.

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