Abstract :
[en] The mass spectra of the
$[{\bf 56, 2^+}]$ and $[{\bf 70, \ell+}]$ multiplets, both belonging to the $N$ = 2 band,
is reviewed in the $1/N_c$ 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 $\mathcal{O}(1/N_c)$ 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 $B_i$ $(i = 1,2,3)$.
This can allow for multiplet assignment of $\Lambda$ and $\Sigma$ hyperons, which generally is quite difficult to make.
Tentative assignments of hyperons with two- and one-star resonances are made to the $[{\bf 70, \ell+}]$ multiplet.
Another important aim is to find out whether or not a common value of the coefficient $c_1$ 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.
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