Mixing of the low-lying three- and five-quarkΩstates with negative parity

Abstract

Mixing of the low-lying three-and five-quark Ω states with spin-parity quantum numbers 1 2 − and 3 2 − is investigated, employing an instanton-induced quark-antiquark pair creation model, which precludes transitions between s 3 and s 4s configurations. Models with hyperfine interactions between quarks of three different kinds, namely, one-gluon-exchange, Goldstone-boson-exchange (GBE) and an instanton-induced interaction (INS) are called OGE, GBE and INS models, respectively. Numerical results show that the instanton-induced pair creation causes strong mixing between the threeand five-quark configurations with spin 3/2, and that this mixing decreases the energy of the lowest spin 3/2 states in all three different hyperfine interaction models to ∼ 1750 ± 50 MeV. On the other hand, transition couplings between s 3 and s 3 qq states with spin 1/2 caused by instanton-induced qq creation is very small and the resulting mixing of three-and five-quark configurations in the OGE and INS models is negligible, while the mixing of the spin 1/2 states in GBE model is not, but effects of this mixing on energies of mixed states are also very small. Accordingly, the lowest Ω states with negative parity in all three hyperfine interactions models have spin 3/2.

Ω baryon spectrum and their decays in a constituent quark model

“…Before 2018, except for the ground state Ω(1672) only three Ω resonances Ω(2250), Ω(2380) and Ω(2470) were listed in the Review of Particle Physics (RPP) [2]. Due to the slow development in experiments, most of the theoretical studies are limited in the calculations of the mass spectrum of the Ω baryon with various methods, such as the Skyrme model [3], the relativistic quark models [4][5][6], the nonrelativistic quark model [7][8][9][10][11][12], the lattice gauge theory [13,14], and so on.…”

Hadronic molecular assignment for the newly observed Ω* state

“…Various models, such as classical quenched quark models with three constituent quarks [1,2], unquenched quark models [3,4] and hadronic dynamical models [5][6][7], gave very different predictions for the Ω * spectrum around 2000 MeV. But experimental knowledge on the Ω * spectrum is very pooras listed in the review of the Particle Data Group [8], where the lowest Ω * state is Ω(2250) with its mass about 600 MeV above the Ω ground state.…”

Possible interpretation of the newly observed Ω(2012) state

“…In various models and methods, such as the Skyrme model [3], quark model [4][5][6][7][8][9][10][11][12][13], lattice gauge theory [14,15] and so on [16][17][18][19][20][21], the masses of the first orbital excitations of Ωð1672Þ are predicted to be ∼2.0 GeV. Thus, the newly observed Ωð2012Þ may be a good candidate for the first orbital (1P) excitations of Ωð1672Þ.…”