Observation of an Excited B + c  State

Robert Appleby; Silvia Borghi; Christopher Burr; Stefano De Capua; Deepanwita Dutta; Evelina Gersabeck; Marco Gersabeck; Lucia Grillo; Martha Hilton; George Lafferty; Andrew Mcnab; Christopher Parkes; Gediminas Sarpis; Mark Williams; The LHCb Collaboration

doi:10.1103/PhysRevLett.122.232001

Observation of an Excited B + c State

Robert Appleby, Silvia Borghi, Christopher Burr, Stefano De Capua, Deepanwita Dutta, Evelina Gersabeck, Marco Gersabeck, Lucia Grillo, Martha Hilton, George Lafferty, Andrew Mcnab, Christopher Parkes, Gediminas Sarpis, Mark Williams, The LHCb Collaboration

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

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+cπ+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+cγ 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 Bc(21S0)+ state. These mass measurements are the most precise to date.

Original language	English
Journal	Physical Review Letters
Early online date	11 Jun 2019
DOIs	https://doi.org/10.1103/PhysRevLett.122.232001
Publication status	Published - 2019

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@article{d7481196938c44c5a8f7a3dd0ab96518,

title = "Observation of an Excited B + c 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 B+c state in the B+cπ+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+cγ 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 Bc(21S0)+ state. These mass measurements are the most precise to date.",

author = "Robert Appleby and Silvia Borghi and Christopher Burr and {De Capua}, Stefano and Deepanwita Dutta and Evelina Gersabeck and Marco Gersabeck and Lucia Grillo and Martha Hilton and George Lafferty and Andrew Mcnab and Christopher Parkes and Gediminas Sarpis and Mark Williams and {The LHCb Collaboration}",

year = "2019",

doi = "10.1103/PhysRevLett.122.232001",

language = "English",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

}

TY - JOUR

T1 - Observation of an Excited B + c State

AU - Appleby, Robert

AU - Borghi, Silvia

AU - Burr, Christopher

AU - De Capua, Stefano

AU - Dutta, Deepanwita

AU - Gersabeck, Evelina

AU - Gersabeck, Marco

AU - Grillo, Lucia

AU - Hilton, Martha

AU - Lafferty, George

AU - Mcnab, Andrew

AU - Parkes, Christopher

AU - Sarpis, Gediminas

AU - Williams, Mark

AU - The LHCb Collaboration,

PY - 2019

Y1 - 2019

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 B+c state in the B+cπ+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+cγ 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 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 B+c state in the B+cπ+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+cγ 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 Bc(21S0)+ state. These mass measurements are the most precise to date.

U2 - 10.1103/PhysRevLett.122.232001

DO - 10.1103/PhysRevLett.122.232001

M3 - Article

SN - 0031-9007

JO - Physical Review Letters

JF - Physical Review Letters

ER -

Observation of an Excited B + c State

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