1 / 21

Fall-apart decay of Q +

Fall-apart decay of Q +. Atsushi Hosaka (RCNP, Osaka Univ). • hep-ph/0409102, to appear in PRD A. Hosaka, M. Oka and T. Shinozaki • hep-ph/0502093, PRD71: 054017 (2005) T. Hyodo and A. Hosaka. Widths & a possible quark model state for Q +. Outline. General remarks Fall apart decay

stephenduncan
Download Presentation

Fall-apart decay 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. Fall-apart decay of Q+ Atsushi Hosaka (RCNP, Osaka Univ) • hep-ph/0409102, to appear in PRD A. Hosaka, M. Oka and T. Shinozaki • hep-ph/0502093, PRD71: 054017 (2005) T. Hyodo and A. Hosaka Widths & a possible quark model state for Q+ Japan-US WS

  2. Outline • General remarks • Fall apart decay Quark model calculation Comments Useful to know what the quark model tells • Possibility of spin 3/2- • Other dynamics . . . . • Conclusion Japan-US WS

  3. Facts ・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) Japan-US WS

  4. 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) Japan-US WS

  5. K-like N-like K Q+ Rearranged V N S-factor Intereaction Fall apart Expected to be a dominant decay mechanism of Q+ Fall apart, or diossociate Japan-US WS

  6. Quark model calculation Useful as a reference for further study Mqq interaction for Japan-US WS

  7. (0s)5 p s Fall apart: form qq(K)+qqq(N) conf. => KN Spectroscopic factor gKNQ ~ 3 G ~ 500 MeV Negative parity Carlson et al, PLB 573, 101 (2003), hep-ph/0307396 SU(6) WF for (l=0)5~ ground state Unique for the antidecuplet Japan-US WS

  8. (0s)40p p s Positive parity More complicated than s-wave due to p-wave excitation MinimizeSpin-Flavor interaction MinimizeSpin-Color (3) Diquark correlation of JW Japan-US WS

  9. Other cases > > JW SC SF (1) Most attractive channel for sf interaction Carlson et al, PRD70, 037501 (2004), hep-ph/0312325, Jennings-Maltman, PRD 69, 094020 (2004), hep-ph/0308286 (q4)SF (q4)CO Japan-US WS

  10. Results (0s)5 1/2ーis dominated by the KN scattering states Japan-US WS

  11. What we have learned: ・Natural width of Pentaquarks 1/2− ~ GeV <= (0s)5 is expanded by KN 1/2＋ < 100 MeV <= Centrifugal force ・Quark model values are consistent with them Most likely (0s)51/2– can not be a narrow resonance 1/2＋with JW-diquark correlation -> 10 MeV (or could be less) Spatial correlation can reduce ~ 1 MeV? Japan-US WS

  12. 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 Japan-US WS

  13. (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 Japan-US WS

  14. KN-like JW-type 1/2– 1/2+ (0s)5 1/2– , (0s)40p 1/2+ can no longer survive Japan-US WS

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

  16. N S Phenomenology of 3/2- baryons Hyodo-Hosaka, hep-ph/0502093, to appear in PRD 8-10 mixing Japan-US WS

  17. • Pick up known resonances of JP = 1/2+ -, 3/2+ - together with Q+ • Fitting into the SU(3) scheme with 8-10 mixing 1/2+ 3/2- Japan-US WS

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

  19. In a string model, fall apart is complicated Sugamoto, Suganuma s u d Other picture (speculation) Quark model ~ fall apart is the most natural Japan-US WS

  20. Role of exotics ~ qq-bar creation is accompanied when a string breaks 4q 5q ~ 3q 2q 5q ~ 5q Could be important in the Q+ production? Japan-US WS

  21. SummaryWe have studied the fall-apart decay of Q+ • Naive quark model values (consistent with natural widths) 1/2– ~ GeV 1/2+ Several tens MeV 3/2– ~ zero or strongly suppressed • Configurations far from KN may provide a narrow width ~ a few MeV is likely with spatial corr. • Full 5-body calculation could change the naïve results • 3/2– is a natural candidate • Beyond the simple fall-apart, with reaction mechanism Japan-US WS

More Related