Regge behaviors in orbitally excited spectroscopy of charmed and bottom baryons

Abstract

Recently, the LHCb Collaboration observed two new bottom baryons, the Ξ b (6227) − and the Σ b (6097) ± , which arouses considerable interest in their inner structures. Stimulated by this, we re-examine the low-lying spectrum of the singly heavy baryons in the heavy quark-diquark picture. Our computation indicates that a linear Regge relation, which is derived from the rotating string model, is sufficient to describe the mass spectrum of all observed singly heavy baryons, predicting that the quantum numbers of the charmed baryons Σ c (2800) and the charm-strange baryon Ξ ′ c (2930), which remain unknown experimentally, are preferably J P = 3/2 − . Similar calculations for the bottom partners support that the newly observed baryons Σ b (6097) − and Ξ ′ b (6227) − are the 1P-wave excitations of the baryons Σ b and Ξ ′ b with J P = 3/2 − . PACS numbers: 14.40.Be, 12.40.Nn, 12.39.Ki ′ b (6227) − . Finally, the paper ends with the discussions and summary in Sec. V. II. SPIN-INDEPENDENT MASSES FOR SINGLY HEAVY BARYONSThe notion of Regge trajectory or Regge mass relation for hadrons, which connects high energy scattering and the spectrum of hadrons in general theory [14], provides us a powerful way to organize the whole spectrum of a given family of the hadrons. In the case of light hadrons, the Regge trajectories are commonly believed to be linear and parallel, and these features are also tested to be true roughly for the SH hadrons in Ref. [24] provided that the hadron mass undergoes a shift M → M − M Q , with M Q the heavy quark mass. As such, one can estimate the spin-averaged masses of Σ c and Ξ ′ c in their P-wave states with the help of the trajectory information of the partner baryons, Λ c and Ξ 0 c , which has the rich data experimentally, and so forth.

Canonical interpretation of the newly observed Λb(6146)0 and ΛbWei1, Lü2, Zhong3 2019Phys. Rev. D356441View full textAdd to dashboardCite

“…With the mixing angle θ ≅ 17°, the Σ b ð6097Þ can be interpreted as the J P ¼ 3=2 − mixing state, where the j¼2 component dominates. This assignment also agrees with other theoretical works [13][14][15][16][17][18]. The branching ratios are BrðΛ b π; Σ b π; Σ Ã b πÞ ¼ 35.0%; 3.5%; 61.5%; ð26Þ which are independent with the overall parameter γ and can be tested by the future experiments.…”

“…It can be seen that the Σ b ð6146Þ and Σ b ð6152Þ as pure Σ b ð1PÞ assignments can be excluded. In the literature, the Σ b ð6097Þ observed by LHCb Collaboration [47] are clarified into the Σ b ð1PÞ states [13][14][15][16][17][18]. Here, we present the our calculations of Σ b ð6097Þ as Σ b ð1PÞ states in Table IX For completeness, we investigate the possibilities of Σ b ð6146Þ, Σ b ð6152Þ, and Σ b ð6097Þ as the P-wave mixing states.…”

“…The Λ b ð5912Þ and Λ b ð5920Þ can be well established as the two λ-mode P-wave Λ b states by various theoretical studies [2][3][4][5][6][8][9][10][11][12]. Under the canonical interpretation, the mass and strong decay behaviors indicate that Σ b ð6097Þ can be categorized into the λ-mode P-wave Σ b states in the literature [13][14][15][16][17][18]. Because of the lack of more experimental information, the spectra of these low-lying bottom baryons have not been established so far [19][20][21][22][23].…”

Bottomonium spectrum in the relativistic flux tube model

“…[53,71]. The RFT model has been applied to study the masses of heavy-light mesons [72][73][74], charmonium states [75], single heavy baryons [54,76], glueballs [77,78], and other exotic hadrons [79].…”

P -wave bottom baryons of the SU(3) flavor 6F

“…More theoretical studies can be found in Refs. [53][54][55][56][57], and we refer to recent reviews for detailed discussions [1,[5][6][7][8]58,59].…”