Observation of Two Excited <i>B<sub>c</sub></i><SUP>+</SUP> States and Measurement of the <i>B<sub>c</sub></i><SUP>+</SUP> (2<i>S</i>) Mass in <i>pp</i> Collisions at √<i>s</i>=13 TeV



Sirunyan, AM, Tumasyan, A, Adam, W, Ambrogi, F, Bergauer, T, Brandstetter, J, Dragicevic, M, Eroe, J, Del Valle, A Escalante, Flechl, M
et al (show 2267 more authors) (2019) Observation of Two Excited <i>B<sub>c</sub></i><SUP>+</SUP> States and Measurement of the <i>B<sub>c</sub></i><SUP>+</SUP> (2<i>S</i>) Mass in <i>pp</i> Collisions at √<i>s</i>=13 TeV. PHYSICAL REVIEW LETTERS, 122 (13). 132001-.

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Abstract

Signals consistent with the B_{c}^{+}(2S) and B_{c}^{*+}(2S) states are observed in proton-proton collisions at sqrt[s]=13  TeV, in an event sample corresponding to an integrated luminosity of 143  fb^{-1}, collected by the CMS experiment during the 2015-2018 LHC running periods. These excited b[over ¯]c states are observed in the B_{c}^{+}π^{+}π^{-} invariant mass spectrum, with the ground state B_{c}^{+} reconstructed through its decay to J/ψπ^{+}. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst)  MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B_{c}^{+}(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(B_{c}^{+})  MeV, where the last term corresponds to the uncertainty in the world-average B_{c}^{+} mass.

Item Type: Article
Uncontrolled Keywords: CMS Collaboration
Depositing User: Symplectic Admin
Date Deposited: 08 May 2019 10:15
Last Modified: 13 Oct 2023 18:13
DOI: 10.1103/PhysRevLett.122.132001
Open Access URL: https://doi.org/10.1103/PhysRevLett.122.132001
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3040248