English

Updated $1/N_c$ expansion analysis of $[{\bf 56, 2^+}]$ and $[{\bf 70, \ell^+}]$ baryon multiplets

High Energy Physics - Phenomenology 2016-05-25 v1

Abstract

The mass spectra of the [56,2+][{\bf 56, 2^+}] and [70,+][{\bf 70, \ell+}] multiplets, both belonging to the NN = 2 band, is reviewed in the 1/Nc1/N_c expansion method. Previous studies, separately made for each multiplet, are presently updated to the 2014 Particle Data Group. The mass formula including corrections up to O(1/Nc)\mathcal{O}(1/N_c) and first order in SU(3) flavor symmetry breaking, has the same independent operator basis in both cases. A special emphasis is made on the role of the SU(3) symmetry breaking operators BiB_i (i=1,2,3)(i = 1,2,3). This can allow for multiplet assignment of Λ\Lambda and Σ\Sigma hyperons, which generally is quite difficult to make. Tentative assignments of hyperons with two- and one-star resonances are made to the [70,+][{\bf 70, \ell+}] multiplet. Another important aim is to find out whether or not a common value of the coefficient c1c_1 of the dominant operator in the mass formula, can well fit the present data in both multiplets. A negative answer, which is here the case, implies distinct Regge trajectories for symmetric and mixed symmetric states.

Keywords

Cite

@article{arxiv.1604.07324,
  title  = {Updated $1/N_c$ expansion analysis of $[{\bf 56, 2^+}]$ and $[{\bf 70, \ell^+}]$ baryon multiplets},
  author = {N. Matagne and Fl. Stancu},
  journal= {arXiv preprint arXiv:1604.07324},
  year   = {2016}
}

Comments

25 pages, to appear in Phys.Rev.D