Observation of an Excited <i>B<sub>c</sub></i><SUP>+</SUP> State



Aaij, R, Beteta, C Abellan, Adeva, B, Adinolfi, M, Aidala, CA, Ajaltouni, Z, Akar, S, Albicocco, P, Albrecht, J, Alessio, F
et al (show 839 more authors) (2019) Observation of an Excited <i>B<sub>c</sub></i><SUP>+</SUP> State. PHYSICAL REVIEW LETTERS, 122 (23). 232001-.

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Abstract

Using pp collision data corresponding to an integrated luminosity of 8.5  fb^{-1} recorded by the LHCb experiment at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, the observation of an excited B_{c}^{+} state in the B_{c}^{+}π^{+}π^{-} invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(B_{c}^{+})  MeV/c^{2}, where the last uncertainty is due to the limited knowledge of the B_{c}^{+} mass. It is consistent with expectations of the B_{c}^{*}(2^{3}S_{1})^{+} state reconstructed without the low-energy photon from the B_{c}^{*}(1^{3}S_{1})^{+}→B_{c}^{+}γ decay following B_{c}^{*}(2^{3}S_{1})^{+}→B_{c}^{*}(1^{3}S_{1})^{+}π^{+}π^{-}. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(B_{c}^{+})  MeV/c^{2}, and is consistent with the B_{c}(2^{1}S_{0})^{+} state. These mass measurements are the most precise to date.

Item Type: Article
Additional Information: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-007.html
Uncontrolled Keywords: LHCb Collaboration
Depositing User: Symplectic Admin
Date Deposited: 15 Aug 2019 08:44
Last Modified: 16 Oct 2023 22:46
DOI: 10.1103/PhysRevLett.122.232001
Open Access URL: http://doi.org/10.1103/PhysRevLett.122.232001
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3051802