Observation of New Resonances in the Λ<i><sub>b</sub></i><SUP>0</SUP>π<SUP>+</SUP>π<SUP>-</SUP> System

Aaij, R, Beteta, C Abellan, Ackernley, T, Adeva, B, Adinolfi, M, Afsharnia, H, Aidala, CA, Aiola, S, Ajaltouni, Z, Akar, S
et al (show 902 more authors) (2019) Observation of New Resonances in the Λ<i><sub>b</sub></i><SUP>0</SUP>π<SUP>+</SUP>π<SUP>-</SUP> System. PHYSICAL REVIEW LETTERS, 123 (15). 152001-.

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We report the observation of a new structure in the Λ_{b}^{0}π^{+}π^{-} spectrum using the full LHCb data set of pp collisions, corresponding to an integrated luminosity of 9  fb^{-1}, collected at sqrt[s]=7, 8, and 13 TeV. A study of the structure suggests its interpretation as a superposition of two almost degenerate narrow states. The masses and widths of these states are measured to be m_{Λ_{b}(6146)^{0}}=6146.17±0.33±0.22±0.16  MeV,m_{Λ_{b}(6152)^{0}}=6152.51±0.26±0.22±0.16  MeV,Γ_{Λ_{b}(6146)^{0}}=2.9±1.3±0.3  MeV,Γ_{Λ_{b}(6152)^{0}}=2.1±0.8±0.3  MeV,with a mass splitting of Δm=6.34±0.32±0.02  MeV, where the first uncertainty is statistical, the second systematic. The third uncertainty for the mass measurements derives from the knowledge of the mass of the Λ_{b}^{0} baryon. The measured masses and widths of these new excited states suggest their possible interpretation as a doublet of Λ_{b}(1D)^{0} states.

Item Type: Article
Additional Information: 17+2 pages, 3+figures, All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-025.html
Uncontrolled Keywords: LHCb Collaboration
Depositing User: Symplectic Admin
Date Deposited: 05 Dec 2019 15:42
Last Modified: 06 Oct 2023 11:15
DOI: 10.1103/PhysRevLett.123.152001
Open Access URL: https://doi.org/10.1103/PhysRevLett.123.152001
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3064997