1 / 29

Decay and production of Q +

Decay and production of Q +. Atsushi Hosaka (RCNP, Osaka Univ). • hep-ph/0409102, PR D71: 074021 (2005) A. H., M. Oka and T. Shinozaki • hep-ph/0502093, PRD71: 054017 (2005) T. Hyodo and A. H. • hep-ph/0505134 , hep-ph/0503149 to appear PRD S.I. Nam, A.H. and H.-Ch. Kim.

harley
Download Presentation

Decay and production of Q +

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. Decay and production of Q+ Atsushi Hosaka (RCNP, Osaka Univ) • hep-ph/0409102, PRD71: 074021 (2005) A. H., M. Oka and T. Shinozaki • hep-ph/0502093, PRD71: 054017 (2005) T. Hyodo and A. H. • hep-ph/0505134, hep-ph/0503149 to appear PRD S.I. Nam, A.H. and H.-Ch. Kim Decay and production mechanism for Q+ (JP) with renewed interest in L(1520) 北京

  2. Facts ~ very narrow width ・In production experiments, G << 20 MeV ・In KN scattering 1 MeV or less G = 1, 5, 10, 20 MeV Sibirtsev et al, PLB599 (2004) 230-235 T. Nakano et al. PRL, 91, 012002 (2003) More data from Nakano in this conference 北京

  3. gn -> K-Q+ vs. gp -> K0Q+ [Q+ or L(1520)] Outline 1. Decay of Q+ General remark Fall-apart in the quark model 2. Possibility of spin 3/2- Phenomenological analysis 3. Photoproduction reconsidered pn asymmetry 北京

  4. 1. Decay ofQ+ 北京

  5. 1/2– S-wave coupling G = 5 GeV Effect of entrifugal barrier~ 50 ! Simple estimate 1/2+ P-wave coupling M* = 1540 MeV, gKNQ ~ 10 G = 100 MeV Empirical fact: gmNN* < 10 (pNN or sNN) 北京

  6. 4q 5q ~ 3q 2q 5q ~ 5q Fall apartdecay Expected to be a dominant process in a constituent QM Fall apart, or diossociate Ni = Nf Other mechanisms? Ni < Nf 北京

  7. K-like N-like K Q+ Rearranged V N S-factor Intereaction Amplitude We consider fall apart in the quark model T ~ <KN|Q+> • Vfi 北京

  8. Interaction ~ Vfi Useful as a reference for further studies Mqq of Yukawa type for 北京

  9. S-factor ~ <KN|Q+> (0s)5 Negative parity ground state (0s)5 p s Carlson et al, PLB 573, 101 (2003) AH et al, Unique ~ AS KN state S-factor gKNQ ~ 3 => G ~ 0.5 - 1 GeV 北京

  10. Positive parity (0s)40p More complicated than s-wave due to p-wave excitation p s We consider MinimizeSpin-Flavor interaction MinimizeSpin-Color (3) Diquark correlation of JW 北京

  11. Spectroscopic factors Carlson et al, PRD70, 037501 (2004), hep-ph/0312325, Jennings-Maltman, PRD 69, 094020 (2004), hep-ph/0308286 SF JW SC > > 北京

  12. Results G(1/2-) >> G(1/2+) 北京

  13. We have seen: ・Natural width of Pentaquarks 1/2− ~ GeV 1/2＋ < 100 MeV <= Centrifugal force ・Quark model values are consistent with them (0s)51/2– : as dominated by KN => can not be a narrow resonance 1/2＋with JW-diquark correlation -> 10 MeV (or could be less) Spatial correlation can reduce ~ 1 MeV? dynamical question 北京

  14. Other possibility Could it be(0s)5 3/2ー • Decay into KN is suppressed due to d-wave • K*(1ー)N dominant but no decay into this channel • No spin partner of 1/2– …. Too broad to see 北京

  15. 2. Phenomenology of 3/2- baryons Hyodo-Hosaka, hep-ph/0502093, PRD71:054017 (2005) 北京

  16. SU(3) description with 8-10 mixing Q+, N1, N2, S1, S2, L, X1, X2 N S 6 parameters 北京

  17. • Choose suitable baryons of JP = 1/2+ -, 3/2+ -, adding Q+-> 6 baryons are enough • Fitting into the SU(3) scheme with 8-10 mixing 1/2+ 3/2- We can fix the mixing angle q 北京

  18. Coupling constants g8 and g10 • qN can be fixed by masses • Two nucleon decay widths determine g8 and g10 • The resulting g10 determines GQ Decay widths GQ (MeV) 北京

  19. 3. Photoproductions 北京

  20. g K0 K+ Q+ p n New data from J-Lab g p -> n K+ K0 Teken from DeVita’s talk at spring APS meeting This is serious, but showing absence of Q+ ? 北京

  21. Theoretical study hep-ph/0505134 Nam-Hosaka-Kim Effective Lagrangian method appears only for n-target 北京

  22. gn -> K- L(1520) and gp -> K0 L(1520) Prior to this was studied and large pn asymmetry was found Nam-Hosaka-Kim, hep-ph/0503149 to appear PRD The role of the contact term (Kroll-Ruderman type) was emphasized 北京

  23. Theta production, JP = 3/2- Total s Log-scale Angular dist Log-scale 北京

  24. The role of the contact term is more important for JP = 3/2- than 1/2+ 北京

  25. Predictions • We see a large asymmetry between pn targets • Cross section for proton ~ few nb is consistent with the upper limit estimated by CLAS 北京

  26. Summary • Fall-apart decay in the quark model 1/2– ~ GeV 1/2+ Several tens MeV could be 10 MeV or less for JW 3/2– ~ zero or strongly suppressed • SU(3) analysis 3/2– is a natural candidate • Photoproduction, revised There is a large pn asymmetry, especially for J = 3/2 No signal from the CLAS does not lead immediately to the absence of Q+ For L(1520), consistent with recent observation of LEPS New data from LEPS is interesting and important => Talk by Takashi Nakano 北京

  27. Comments A related work Melokov, Simula and Stech, PLB 594 (2004) 265 Claimed that G ~ 150 MeV for the JW wf Assumption In the quark model, there is no pole (hA) term ==> Can not be applied to the quark model 北京

  28. (2) 5-body calculation Recent calculation by Hiyama Gaussian Expansion Method + + . . . KN Scattering state Confined state Fall apart when R→∞ Coupling to other channels including KN changes the nature of the confined state drastically 北京

  29. KN-like JW-type 1/2– 1/2+ (0s)5 1/2– , (0s)40p 1/2+ can no longer survive 北京

More Related