Mesonic fluctuations in a nonlocal NJL model

Jul, 2000
21 pages
Published in:
  • Nucl.Phys.A 703 (2002) 717-744
e-Print:
Report number:
  • MC-TH-00-05

Citations per year

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Abstract:
The effects of meson fluctuations are studied in a nonlocal generalization of the Nambu-Jona-Lasinio model, by including terms of next-to-leading order (NLO) in 1/N_c. In the model with only scalar and pseudoscalar interactions NLO contributions to the quark condensate are found to be very small. This is a result of cancellation between virtual mesons and Fock terms, which occurs for the parameter sets of most interest. In the quark self-energy, similar cancellations arise in the tadpole diagrams, although not in other NLO pieces which contribute at the \sim 25% level. The effects on pion properties are also found to be small. NLO contributions from real ππ\pi\pi intermediate states increase the sigma meson mass by 30\sim 30%. In an extended model with vector and axial interactions, there are indications that NLO effects could be larger.
Note:
  • 22 pages (RevTeX), 12 figures (using graphicx.sty), v3 has improved numerics Report-no: TH/00/05
  • 11.15.Pg
  • 12.39.Ki
  • 11.30.Rd
  • Nambu–Jona-Lasinio model
  • Nonlocal interactions
  • Chiral symmetry
  • 1/ N c expansion
  • Sigma meson
  • 1/ Nc expansion
  • Jona-Lasinio-Nambu model: nonlocal