Observation of Two New Excited ?<SUP>0</SUP><sub>b</sub> States Decaying to ?<SUP>0</SUP><sub>b</sub>K -?<SUP>+</SUP>

Aaij, R, Abdelmotteleb, ASW, Beteta, C Abellan, Ackernley, T, Adeva, B, Adinolfi, M, Afsharnia, H, Agapopoulou, C, Aidala, CA, Aiola, S
et al (show 999 more authors) (2022) Observation of Two New Excited ?<SUP>0</SUP><sub>b</sub> States Decaying to ?<SUP>0</SUP><sub>b</sub>K -?<SUP>+</SUP>. PHYSICAL REVIEW LETTERS, 128 (16). 162001-.

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Two narrow resonant states are observed in the Λ_{b}^{0}K^{-}π^{+} mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6  fb^{-1}. The minimal quark content of the Λ_{b}^{0}K^{-}π^{+} system indicates that these are excited Ξ_{b}^{0} baryons. The masses of the Ξ_{b}(6327)^{0} and Ξ_{b}(6333)^{0} states are m[Ξ_{b}(6327)^{0}]=6327.28_{-0.21}^{+0.23}±0.12±0.24 and m[Ξ_{b}(6333)^{0}]=6332.69_{-0.18}^{+0.17}±0.03±0.22  MeV, respectively, with a mass splitting of Δm=5.41_{-0.27}^{+0.26}±0.12  MeV, where the uncertainties are statistical, systematic, and due to the Λ_{b}^{0} mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξ_{b}(6327)^{0}]<2.20(2.56) and Γ[Ξ_{b}(6333)^{0}]<1.60(1.92)  MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξ_{b}^{0} resonances.

Item Type: Article
Uncontrolled Keywords: LHCb Collaboration
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 17 May 2022 14:11
Last Modified: 16 Oct 2023 16:17
DOI: 10.1103/PhysRevLett.128.162001
Open Access URL: https://journals.aps.org/prl/abstract/10.1103/Phys...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3154965