1 / 20

Pentaquark at KEK

K.Imai: Exotics 04/2/18 (Kyoto). Pentaquark at KEK. K.Imai (Kyoto) Introduction Width and spin-parity of Q + Proposed experiment at KEK-PS Summary. Discovery of Pentaquark Q +. M = 1540 10 MeV G < 25 MeV Gaussian significance 4.6 s. Renaissance of hadron spectroscopy !.

lore
Download Presentation

Pentaquark at KEK

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. K.Imai: Exotics 04/2/18 (Kyoto) Pentaquark at KEK K.Imai (Kyoto) • Introduction • Width and spin-parity of Q+ • Proposed experiment at KEK-PS • Summary

  2. Discovery of PentaquarkQ+ M = 154010 MeV G < 25 MeV Gaussian significance 4.6s Renaissance of hadron spectroscopy ! background T. Nakano et al., Phys.Rev.Lett. 91 (2003) 012002

  3. Questions about Q+ Spin-parity: Jp= ½+ or ½- or 3/2 -> selection of models s-wave or p-wave ? K+n -> K+n phase shift analysis pol.g N -> K- Q+ decay distribution of Q+ angular dependence -> SPring-8 TPC project

  4. Only upper limit for width CLAS/JLAB DIANA/ITEP g d → p K+ K-n K+Xe → K0p X (K+n→ K0p) M = 15392 MeV G < 9 MeV M = 15425 MeV G < 21 MeV hep-ex/0304040 hep-ex/0307018

  5. CLAS/Jlab hep-ex/0307088 SAPHIR/ELSA hep-ex/0307083 M = 153710 MeV G < 32 MeV M = 153710 MeV G < 32 MeV M = 154042 MeV G < 25 MeV

  6. Question about width • upper limit from direct measurement: 9 (20) MeV • S.Nussinov (hep-ph/0307357) based on K+d scattering data G(Q+)<6MeV • Arndt,Strakovski & Workman (nucl-th/0308012) based on existing K+N elastic scattering data G(Q+) as small as 1 MeV

  7. High resolution spectroscopy of pentaquark Q+ (proposal to KEK-PS) • K.Imai, K.Miwa, M.Hayata, M.Miyabe, N.Muramatsu, M.Niiyama, N.Saito, M.Wagner, M.Yosoi (Kyoto U.) • T.Nagae, M.Ieiri, N.Noumi, Y.Sato, S.Sawada, M.Sekimoto, H.Takahashi, A.Toyoda (KEK) • H.Fujioka, T.Maruta (U. Tokyo) • T.Fukuda, P.K.Saha (Osaka ECU) • T.Nakano (RCNP) • K.Hicks (Ohio) • K+ p ->p+ Q+ reaction with SKS spectrometer at KEK K6 beam line • excellent mass resolution DE=1.0 MeV • Decay angular distribution for spin determination

  8. SKS spectrometer

  9. L12C hypernucleus with SKS Best energy resolution ∆E(FWHM)=1.45 MeV 2.0 MeV

  10. Missing mass resolution for K+p ->p+Q+

  11. Yield and background • Cross section: 80mb at P(K+)=1.2GeV/c ? (Y.Oh et al., hep-ph/0311054) • Yield: 3500/60shift • Background reactions (K+,p+) ( R.Bland et al., Nucl. Phys. B13 (1969) 595) • K+p -> K0D+(p+p) 3.4 +- 0.3 mb • K+p -> K+D+(p+n) 0.3 +- 0.1 mb • K+p -> K*(K0p+) p 1.1 +- 0.2 mb • K+p -> K0p+ p (3-body) 0.25 +- 0.30 mb • K+p -> K+p+ n (3-body) 0.24 +- 0.06 mb

  12. Simulation (width=0)

  13. Simulation (width=1MeV)

  14. Simulation (width=8MeV)

  15. Expected Statistical Significance (width vs cross section)

  16. Dalitz Plot

  17. E522 (KEK-PS) • Search for H-dibaryon resonance via 12C(K-,K+LL) and study of XN interactions C.J.Yoon tomorrow by-product ? Q+ search by p(p-,K-) Q+ at p(p-)=1.9 GeV/c (under analysis) No peak was observed in old BC data (poor statistics)

  18. Summary Penta-quark (Q+) needs further confirmation by hadron induced reactions. p- p ->K- Q+, K+ p ->p+ Q+, , , • Width and spin-parity must be determined • High resolution spectroscopy of Q+ is proposed with SKS spectrometer at KEK DE=1MeV ! • Decay angular distribution for spin assignment

  19. To establish anti-decuplet • X- - n K- -> K+X- - , p K- -> K+p+X- - • X+ p K- -> K0p- X+ S=-2 S=0 Diakonov 2070 1710 MeV Jaffe, Wilczek 1750 1440 MeV • If M(X--) ~ 1750 MeV (Jaffe & Wilczek, hep-ph/0307341) >2GeV/c K- beam (BNL or KEK or (J-PARC)) !

  20. S=-2 Penta-quark X-- NA49 collaborationM=1862 MeV G<18 MeVhep-ex/0310014 5.6s

More Related