Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV

CMS Collaboration

doi:10.1103/PhysRevLett.122.132001

Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV

CMS Collaboration

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101 Citations (Scopus)

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.

Original language	English
Article number	132001
Journal	Physical review letters
Volume	122
Issue number	13
DOIs	https://doi.org/10.1103/PhysRevLett.122.132001
Publication status	Published - 2019 Apr 2

Bibliographical note

Publisher Copyright:
© 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.

ASJC Scopus subject areas

General Physics and Astronomy

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10.1103/PhysRevLett.122.132001

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@article{66e18e80f9fc40c7af9d35e10e05f8b3,

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 S. Choi and B. Hong and Park, {S. K.} and J. Yoo",

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",

volume = "122",

journal = "Physical review letters",

issn = "0031-9007",

publisher = "American Physical Society",

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T1 - Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV

AU - CMS Collaboration

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Ambrogi, F.

AU - Bergauer, T.

AU - Brandstetter, J.

AU - Dragicevic, M.

AU - Erö, J.

AU - Escalante Del Valle, A.

AU - Flechl, M.

AU - Frühwirth, R.

AU - Jeitler, M.

AU - Krammer, N.

AU - Krätschmer, I.

AU - Liko, D.

AU - Madlener, T.

AU - Mikulec, I.

AU - Rad, N.

AU - Schieck, J.

AU - Schöfbeck, R.

AU - Spanring, M.

AU - Spitzbart, D.

AU - Waltenberger, W.

AU - Wittmann, J.

AU - Wulz, C. E.

AU - Zarucki, M.

AU - Drugakov, V.

AU - Mossolov, V.

AU - Suarez Gonzalez, J.

AU - Darwish, M. R.

AU - De Wolf, E. A.

AU - Di Croce, D.

AU - Janssen, X.

AU - Lauwers, J.

AU - Lelek, A.

AU - Pieters, M.

AU - Van Haevermaet, H.

AU - Van Mechelen, P.

AU - Van Remortel, N.

AU - Blekman, F.

AU - Bols, E. S.

AU - Chhibra, S. S.

AU - D'Hondt, J.

AU - De Clercq, J.

AU - Flouris, G.

AU - Lontkovskyi, D.

AU - Choi, S.

AU - Hong, B.

AU - Park, S. K.

AU - Yoo, J.

N1 - Publisher Copyright: © 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.

PY - 2019/4/2

Y1 - 2019/4/2

N2 - 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.

AB - 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.

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U2 - 10.1103/PhysRevLett.122.132001

DO - 10.1103/PhysRevLett.122.132001

M3 - Article

C2 - 31012626

AN - SCOPUS:85064123792

SN - 0031-9007

VL - 122

JO - Physical review letters

JF - Physical review letters

IS - 13

M1 - 132001

ER -

Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV

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