Evidence of a <i>J</i>/ψΛ structure and observation of excited Ξ<SUP>-</SUP> states in the Ξ<i><sub>b</sub></i><SUP>-</SUP> → <i>J</i>/ψΛ<i>K</i><SUP>-</SUP> decay



Aaij, R, Beteta, C Abellan, Ackernley, T, Adeva, B, Adinolfi, M, Afsharnia, H, Aidala, CA, Aiola, S, Ajaltouni, Z, Akar, S
et al (show 959 more authors) (2021) Evidence of a <i>J</i>/ψΛ structure and observation of excited Ξ<SUP>-</SUP> states in the Ξ<i><sub>b</sub></i><SUP>-</SUP> → <i>J</i>/ψΛ<i>K</i><SUP>-</SUP> decay. SCIENCE BULLETIN, 66 (13). pp. 1278-1287.

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Abstract

First evidence of a structure in the J/ψΛ invariant mass distribution is obtained from an amplitude analysis of Ξ<sub>b</sub><sup>-</sup>→J/ψΛK<sup>-</sup> decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1σ including systematic uncertainties and look-elsewhere effect. Its mass and width are determined to be 4458.8±2.9<sub>-1.1</sub><sup>+4.7</sup>MeV and 17.3±6.5<sub>-5.7</sub><sup>+8.0</sup>MeV, respectively, where the quoted uncertainties are statistical and systematic. The structure is also consistent with being due to two resonances. In addition, the narrow excited Ξ<sup>-</sup> states, Ξ1690<sup>-</sup> and Ξ1820<sup>-</sup>, are seen for the first time in a Ξ<sub>b</sub><sup>-</sup> decay, and their masses and widths are measured with improved precision. The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb<sup>-1</sup>, collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV.

Item Type: Article
Additional Information: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2020-039.html (LHCb public pages)
Uncontrolled Keywords: QCD, Exotics, Pentaquark, Spectroscopy, Quarkonium, Particle and resonance production
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 02 Sep 2021 08:57
Last Modified: 13 Oct 2023 20:11
DOI: 10.1016/j.scib.2021.02.030
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3134984