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∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+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(2S10)+ state. These mass measurements are the most precise to date.

Original language	English
Article number	232001
Journal	Physical Review Letters
Volume	122
Issue number	23
DOIs	https://doi.org/10.1103/PhysRevLett.122.232001
Publication status	Published - 11 Jun 2019

ASJC Scopus subject areas

Physics and Astronomy(all)

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10.1103/PhysRevLett.122.232001

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(LHCb Collaboration), & Wagner, A. R. (2019). Observation of an Excited Bc+ State. Physical Review Letters, 122(23), [232001]. https://doi.org/10.1103/PhysRevLett.122.232001

@article{b61965c593e44fa4b996a6e5920b0dc6,

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∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+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(2S10)+ 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 A. Baranov and Barlow, {R. J.} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and V. Batozskaya and B. Batsukh and A. Battig and V. Battista and A. Bay and F. Bedeschi and A. Petrov and S. Strokov and Wagner, {Alexander Rudolfovich}",

year = "2019",

month = jun,

day = "11",

doi = "10.1103/PhysRevLett.122.232001",

language = "English",

volume = "122",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

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 - Baranov, A.

AU - Barlow, R. J.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - Baryshnikov, F.

AU - Batozskaya, V.

AU - Batsukh, B.

AU - Battig, A.

AU - Battista, V.

AU - Bay, A.

AU - Bedeschi, F.

AU - Petrov, A.

AU - Strokov, S.

AU - Wagner, Alexander Rudolfovich

PY - 2019/6/11

Y1 - 2019/6/11

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∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+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(2S10)+ 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∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+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(2S10)+ 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

M3 - Article

AN - SCOPUS:85067367011

VL - 122

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

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M1 - 232001

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