The role of components in the nucleon and the resonance

Autor: B. Juliá-Díaz, D.O. Riska
Rok vydání: 2006
Předmět:
Zdroj: Nuclear Physics A. 780:175-186
ISSN: 0375-9474
DOI: 10.1016/j.nuclphysa.2006.09.016
Popis: The role of q q ¯ components in the nucleon and the N ( 1440 ) resonance is studied by explicit coupling of the lowest positive parity q q q q q ¯ state to the qqq components in the harmonic oscillator quark model. The lowest energy q q q q q ¯ component, where the 4-quark subsystem has the flavor–spin symmetry [ 4 ] F S [ 22 ] F [ 22 ] S , is close in energy to the lowest positive parity excitation of the nucleon in the qqq quark model. The confining interaction leads to a strong mixing of the q q q q q ¯ system and the positive parity excited state of the qqq system. This result is in line with the phenomenological indications for a two-component structure of the N ( 1440 ) resonance. The presence of substantial q q ¯ components in the N ( 1440 ) can bring about a reconciliation of the constituent quark model with the large empirical decay width of the N ( 1440 ) .
Databáze: OpenAIRE