@article{a557bcfdf7024194b380143ba2d5496d,
title = "Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV",
abstract = "Signals consistent with the Bc+(2S) and Bc∗+(2S) states are observed in proton-proton collisions at 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 bc states are observed in the Bc+π+π- invariant mass spectrum, with the ground state Bc+ 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 Bc+(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(Bc+) MeV, where the last term corresponds to the uncertainty in the world-average Bc+ mass.",
author = "\{CMS Collaboration\} and Sirunyan, \{A. M.\} and A. Tumasyan and W. Adam and F. Ambrogi and T. Bergauer and J. Brandstetter and M. Dragicevic and J. Er{\"o} and \{Escalante Del Valle\}, A. and M. Flechl and R. Fr{\"u}hwirth and M. Jeitler and N. Krammer and I. Kr{\"a}tschmer and D. Liko and T. Madlener and I. Mikulec and N. Rad and J. Schieck and R. Sch{\"o}fbeck and M. Spanring and D. Spitzbart and W. Waltenberger and J. Wittmann and Wulz, \{C. E.\} and M. Zarucki and V. Drugakov and V. Mossolov and \{Suarez Gonzalez\}, J. and Darwish, \{M. R.\} and \{De Wolf\}, \{E. A.\} and \{Di Croce\}, D. and X. Janssen and J. Lauwers and A. Lelek and M. Pieters and \{Van Haevermaet\}, H. and \{Van Mechelen\}, P. and \{Van Remortel\}, N. and F. Blekman and Bols, \{E. S.\} and Chhibra, \{S. S.\} and J. D'Hondt and \{De Clercq\}, J. and G. Flouris and D. Lontkovskyi and Marlow, \{Daniel Robert\} and Ojalvo, \{Isobel Rose\} and Olsen, \{James D.\} and Tully, \{Christopher George\}",
note = "Publisher Copyright: {\textcopyright} 2019 CERN for the CMS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.",
year = "2019",
month = apr,
day = "2",
doi = "10.1103/PhysRevLett.122.132001",
language = "English (US)",
volume = "122",
journal = "Physical review letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "13",
}