Observation of an Excited Bc+ State

LHCb Collaboration

doi:10.1103/PhysRevLett.122.232001

Observation of an Excited B_c⁺ State

LHCb Collaboration

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

25 Citations (Scopus)

112 Downloads (Pure)

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 √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/c², where the last uncertainty is due to the limited knowledge of the B_c⁺ mass. It is consistent with expectations of the B_c^∗(2³S₁)⁺ state reconstructed without the low-energy photon from the B_c^∗(1³S₁)⁺→B_c⁺γ decay following B_c^∗(2³S₁)⁺→B_c^∗(1³S₁)⁺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/c², and is consistent with the B_c(2¹S₀)⁺ state. These mass measurements are the most precise to date.

Original language	English
Article number	232001
Number of pages	10
Journal	Physical Review Letters
Volume	122
Issue number	23
Early online date	11 Jun 2019
DOIs	https://doi.org/10.1103/PhysRevLett.122.232001
Publication status	Published - 14 Jun 2019

ASJC Scopus subject areas

Physics and Astronomy(all)

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Cite this

@article{34d2a58e673e451797598b24e3da0abc,

title = "Observation of an Excited Bc+ State",

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 √s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(23S1)+ state reconstructed without the low-energy photon from the Bc∗(13S1)+→Bc+γ decay following Bc∗(23S1)+→Bc∗(13S1)+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(Bc+) MeV/c2, and is consistent with the Bc(21S0)+ state. These mass measurements are the most precise to date.",

author = "{LHCb Collaboration} and R. Aaij and {Abell{\'a}n Beteta}, C. and B. Adeva and M. Adinolfi and Aidala, {C. A.} and Z. Ajaltouni and S. Akar and P. Albicocco and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and G. Alkhazov and {Alvarez Cartelle}, P. and Alves, {A. A.} and S. Amato and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and Andrews, {J. E.} and F. Archilli and P. D'Argent and {Arnau Romeu}, J. and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and Back, {J. J.} and S. Baker and V. Balagura and W. Baldini and S. Bifani and R. Calladine and G. Chatzikonstantinidis and N. Farley and P. Griffith and P. Ilten and C. Lazzeroni and L. Pescatore and J. Plews and D. Popov and A. Sergi and Slater, {M. W.} and Watson, {N. K.} and Zarebski, {K. A.}",

year = "2019",

month = jun,

day = "14",

doi = "10.1103/PhysRevLett.122.232001",

language = "English",

volume = "122",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society (APS)",

number = "23",

}

TY - JOUR

T1 - Observation of an Excited Bc+ State

AU - LHCb Collaboration

AU - Aaij, R.

AU - Abellán Beteta, C.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Aidala, C. A.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albicocco, P.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Alfonso Albero, A.

AU - Alkhazov, G.

AU - Alvarez Cartelle, P.

AU - Alves, A. A.

AU - Amato, S.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andreassi, G.

AU - Andreotti, M.

AU - Andrews, J. E.

AU - Archilli, F.

AU - D'Argent, P.

AU - Arnau Romeu, J.

AU - Artamonov, A.

AU - Artuso, M.

AU - Arzymatov, K.

AU - Aslanides, E.

AU - Atzeni, M.

AU - Audurier, B.

AU - Bachmann, S.

AU - Back, J. J.

AU - Baker, S.

AU - Balagura, V.

AU - Baldini, W.

AU - Bifani, S.

AU - Calladine, R.

AU - Chatzikonstantinidis, G.

AU - Farley, N.

AU - Griffith, P.

AU - Ilten, P.

AU - Lazzeroni, C.

AU - Pescatore, L.

AU - Plews, J.

AU - Popov, D.

AU - Sergi, A.

AU - Slater, M. W.

AU - Watson, N. K.

AU - Zarebski, K. A.

PY - 2019/6/14

Y1 - 2019/6/14

N2 - 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 √s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(23S1)+ state reconstructed without the low-energy photon from the Bc∗(13S1)+→Bc+γ decay following Bc∗(23S1)+→Bc∗(13S1)+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(Bc+) MeV/c2, and is consistent with the Bc(21S0)+ state. These mass measurements are the most precise to date.

AB - 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 √s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(23S1)+ state reconstructed without the low-energy photon from the Bc∗(13S1)+→Bc+γ decay following Bc∗(23S1)+→Bc∗(13S1)+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(Bc+) MeV/c2, and is consistent with the Bc(21S0)+ state. These mass measurements are the most precise to date.

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U2 - 10.1103/PhysRevLett.122.232001

DO - 10.1103/PhysRevLett.122.232001

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JO - Physical Review Letters

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