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
N1 - Funding Information:
We thank Chao-Hsi Chang and Xing-Gang Wu for frequent and interesting discussions on the production of the mesons. We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland) and OSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany); EPLANET, Marie Skłodowska-Curie Actions and ERC (European Union); ANR, Labex P2IO and OCEVU, and Région Auvergne-Rhóne-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Royal Society and the Leverhulme Trust (United Kingdom); Laboratory Directed Research and Development program of LANL (USA).
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
IS - 23
M1 - 232001
ER -