$$\varLambda $$ and $$\varSigma $$ Excitations and the Quark Model

Abstract

The spectrum of $$\varLambda $$ Λ and $$\varSigma $$ Σ excitations is reviewed taking into account (nearly) all hyperon resonances which were seen in early analyses or in one of the recent partial-wave analyses. The spectrum is compared with the old Isgur–Karl model and the Bonn model. These models allows us to discuss the SU(3) structure of the observed resonances. The SU(3) decomposition is compared with SU(6) relations between the different decay modes. Seven $$\varLambda $$ Λ states are proposed to be classified as SU(3) singlet states. The hyperon spectrum is compared with the spectrum of N and $$\varDelta $$ Δ resonances.

Spectroscopic investigation of light strange S = −1 Λ and Σ and S = −2 Ξ baryons

“…Also, two pole structure of Λ(1405) is analyzed using chiral effective field theory [17]. E. Klempt et al has extensively reviewed the Λ and Σ hyperon spectrum based on experimental and theoretical studies focusing on all the known states of the spectrum [18]. These spectrums are studied through photoproduction off the proton in ref [19].…”

A possible interpretation of $Λ$ baryon spectrum with pentaquark components

“…This resonance Λ(1710) reported by KSU [7] in 2013 is interpreted as the Λ * (70, 2 1, 2, 0 + ) singlet state in Ref. [14], but it can't be described by the relativistic interacting quark-diquark models [28,29]. Though a higher mass is predicted for the flavor-singlet state Λ * (70, 2 1, 2, 0 + ) in the work, we may tentatively assign the 1-star Λ(1710) resonance as the Λ * (70, 2 1, 2, 0 + ) state, considering the huge width of the Λ(1710) resonance.…”

“…Recent data analyses have confirmed most 3* and 4* Λ states, but derived rather different information of some little known states. Recent couple channel analyses from the Kent group (KSU) and JLab have extracted more hyperons [7][8][9][10][11][12][13][14]. The Kent group found some new states like Λ(1710)1/2 + and Λ(2050)3/2 − , which were listed in Particle Data Group (PDG) [6] with one star, by fitting partial-wave amplitudes using multichannel parametrization [7].…”

“…A dynamical coupledchannel model applied by the Osaka group [8,9] results in no clear existence of Λ(1710), Λ(1800), Λ (2000) and Λ(2050). Bonn-Gatchina (BnGa) group has recently reported Λ(1710)1/2 + , Λ(2070)3/2 + and Λ(2080)5/2 − , suggesting all the states together with Λ(1405)1/2 − as SU(3) singlet states [11][12][13][14]. The experimental data from K − p induced reactions have made a great contribution to our knowledge of the Λ baryon spectrum, but it is still insufficient to reveal the nature of all Λ resonances.…”

The $Λ(1405)$ resonance as a genuine three-quark or molecular state

“…Fernández-Ramírez et al [40] have discovered that the pole near the KN threshold belongs to the 0 − leading Regge trajectory and therefore is most likely dominated by the ordinary three-quark configuration. Similarly Klempt et al [41] conclude that one of the two states found as poles below the KN threshold has to be assigned to the predicted quark-model state.…”