Interpretation of the newly discovered Ω(2012)

Abstract

The theoretical calculations of different parameters of hadrons and comparison of the obtained results with existing experimental data not only test our present knowledge on these states but also provide insights into the search for new states. Despite the fact that, in the hadronic sector, many particles have been observed and their properties intensively studied, there is still much work to do. Even for the hadrons containing only the light quarks, their excited states require more investigation. The quark model predicts some baryonic excited states that have not yet been observed in the experiment. Searching for these missing baryon resonances attracts attention of not only the experimentalists but also the theoreticians. To understand and identify such states, it is necessary to broaden the studies on these baryons.As a result of these circumstances, the recent observation of the Belle Collaboration has attracted much attention. They reported observation of Ωð2012Þ with mass 2012.4 AE 0.7ðstatÞ AE 0.6ðsystÞ MeV and width 6.4 þ2.5 −2.0 ðstatÞ AE 1.6ðsystÞ MeV [1] with a conclusion that it has more likely a spin-parity J P ¼ 3=2 − . To date, there are a few Ω baryons listed in the Particle Data Group (PDG) [2]. Only one of them, which is the ground state Ωð1672Þ, is well established; we lack certain knowledge of the nature of the others. To identify the spectrum of the Ω states, the first orbital excitation of the Ωð1672Þ state was investigated with different models. The quark model [3][4][5][6][7][8][9][10][11], lattice gauge theory [12,13], and Skyrme model [14] are among those studies whose predictions gave mass values that are consistent with the experimental result of the Belle Collaboration. This may be taken as support for Ωð2012Þ being an orbital excitation of Ωð1672Þ. To identify the properties of the Ωð2012Þ baryon, it would also be helpful to investigate its other properties besides the mass. Its strong decay was studied recently in [15], using the chiral quark model, and as a result, the possibility of Ωð2012Þ being J P ¼ 3=2 − was underlined; however, it also stated that the results obtained for the possibility of it being J P ¼ 1=2 − or J P ¼ 3=2 þ are consistent with the results of the Belle Collaboration within the uncertainties. There are also some studies on the radiative decays [16] and magnetic moments of negative parity baryons [17,18].References [3,19] present the predictions on the mass of radially excited decuplet baryons. The prediction of [3] for the 2S state is 2065 MeV and it is close to the mass of Ωð2012Þ. On the other hand, the prediction given by Ref. [19] is 2176 AE 219 MeV obtained using the QCD sum rule method. If we consider the central value of this result, it is larger than the observed mass of Ωð2012Þ. Therefore, in order to get new information about the identification of the nature of Ωð2012Þ, it is necessary to investigate the mass of the orbital excitation of Ωð1672Þ, which we represent as an excited Ω state in the remaining part of the discussion. Taking this motivati...

Strong decay modes K¯Ξ and K¯Ξπ of the Huang1, Liu2, Lu3 et al. 2018Phys. Rev. D

“…Indeed, our study shows that the contribution from the ηΩ component is small. Note that the molecule picture is different from the qqq picture of the chiral quark model [14] and light cone QCD sum rules [15,16].…”

“…In Ref. [15], the mass and residue of the Ωð2012Þ were calculated by employing the QCD sum rule method with the conclusion that the Ωð2012Þ could be a 1P orbitally excited Ω state with J P ¼ 3=2 − . The analysis of Ref.…”

Search for Ω(2012)→KΞ(1530)→<

“…The observed spacing in the Ω mass spectrum between the ground state and this excited state (∼340 MeV=c 2 ) is smaller than that for other Ω − excited states [2], and is more similar to the negative-parity orbital excitations of many other baryon pairs such as Λ and Λð1405Þ or Λ þ c and Λ þ c ð2595Þ. After the initial observation of the Ωð2012Þ, several theoretical interpretations of that state were offered [3][4][5][6][7][8][9][10][11]. Although it is generally accepted that Ωð2012Þ is a 1P orbital excitation of the ground-state Ω baryon with quark content sss and quantum numbers J P ¼ 3 2 − , Refs.…”

Coupled channels dynamics in the generation of the $$\Omega (2012)$$ Ω ( 2012 ) resonance

“…The existence of excited states, like for any other baryon, is predicted in the quark models by means of the excitations of the quarks [2][3][4][5][6]. Large N c considerations [7], QCD sum rules [8,9], the Skyrme model [10] and lattice QCD simulations [11] have also added information to this subject. Extensions of quark models which would accommodate five quark components [12][13][14] lead to more binding than the original ones of Refs.…”