Observation of ExcitedΛb0Baryons

Abstract

Using pp collision data corresponding to 1:0 fb À1 integrated luminosity collected by the LHCb detector, two narrow states are observed in the à 0 b % þ % À spectrum with masses 5911:97 AE 0:12ðstatÞ AE 0:02ðsystÞ AE 0:66ðà 0 b massÞ MeV=c 2 and 5919:77 AE 0:08ðstatÞ AE 0:02ðsystÞ AE 0:66ðà 0 b massÞ MeV=c 2 . The significances of the observations are 5.2 and 10.2 standard deviations, respectively. These states are interpreted as the orbitally excited à 0 b baryons, à Ã0 b ð5912Þ and à Ã0 b ð5920Þ.

Open bottom states and theB¯-meson propagation in hadronic matter

“…For baryons we have also determined several J ¼ 1=2 and J ¼ 3=2 states in the Λ b and Σ b sectors which form HQSS doublets. This is the case for the Λ b ð5910Þ and Λ Ã b ð5921Þ, which can be identified with the states observed by the LHCb Collaboration [28]. Furthermore, we have associated one of our states, the J ¼ 3=2 Σ Ã b ð5904Þ, to be the bottom counterpart of the experimental strange Σ Ã ð1670Þ and predicted charmed Σ Ã c ð2550Þ resonances; though not experimentally detected yet but a clear case for discovery.…”

“…However, in this latter work only the states coming from the most attractive SU(8) representations, the 120 and 168 irrep, were considered while the weakly attractive 4572 was disregarded. Moreover, the focus of this previous paper was the study of the recently discovered Λ b ð5912Þ and Λ b ð5920Þ states [28]. In the present paper we aim at studying theBN andBΔ interactions to analyze the corresponding scattering amplitudes and, hence, the cross sections for theB propagation in matter.…”

Observation of a New Ξb− Resonance

“…Beyond these lowest-lying states, a spectrum of heavier states is expected [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], where there are either radial or orbital excitations amongst the constituent quarks. The only such states discovered thus far in the b-baryon sector are the Λ b ð5912Þ 0 and Λ b ð5920Þ 0 resonances [24], which are consistent with being orbital excitations of the Λ 0 b baryon. In this Letter, we report the first observation of a new state, decaying into both Λ 0 b K − and Ξ 0 b π − , using samples of pp collision data collected with the LHCb experiment at 7, 8, and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0, and 1.5 fb −1 , respectively.…”

Analysis of Λc(2595) , Λc(2625)Kawakami1, Harada2 2018Phys. Rev. D282300View full textAdd to dashboardCite

“…The properties of these states have been studied experimentally and theoretically (see, e.g., Refs. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and references therein). In the present analysis, we compare our predictions of the decay widths with other available predictions by quark models [12,13] and chiral effective models [14,15].…”