Observation of an Excited B c + State

Observation of an Excited B c + State

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...

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Veröffentlicht in:Physical review letters 2019-06, Vol.122 (23), Article 232001
Hauptverfasser: Aaij, R., Abellán Beteta, C., Adeva, B., Adinolfi, M., Aidala, C. A., Ajaltouni, Z., Akar, S., Albicocco, P., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Alkhazov, G., Alvarez Cartelle, P., Alves, A. A., Amato, S., Amhis, Y., An, L., Anderlini, L., Andreassi, G., Andreotti, M., Andrews, J. E., Archilli, F., d’Argent, P., Arnau Romeu, J., Artamonov, A., Artuso, M., Arzymatov, K., Aslanides, E., Atzeni, M., Audurier, B., Bachmann, S., Back, J. J., Baker, S., Balagura, V., Baldini, W., Baranov, A., Barlow, R. J., Barsuk, S., Barter, W., Bartolini, M., Baryshnikov, F., Batozskaya, V., Batsukh, B., Battig, A., Battista, V., Bay, A., Bedeschi, F., Bediaga, I., Beiter, A., Bel, L. J., Belin, S., Beliy, N., Bellee, V., Belloli, N., Belous, K., Ben-Haim, E., Bencivenni, G., Benson, S., Beranek, S., Berezhnoy, A., Bernet, R., Berninghoff, D., Bertholet, E., Bertolin, A., Betancourt, C., Betti, F., Bettler, M. O., van Beuzekom, M., Bezshyiko, Ia, Bhasin, S., Bhom, J., Bieker, M. S., Bifani, S., Billoir, P., Birnkraut, A., Bizzeti, A., Bjørn, M., Blago, M. P., Blake, T., Blanc, F., Blusk, S., Bobulska, D., Bocci, V., Boente Garcia, O., Boettcher, T., Bondar, A., Bondar, N., Borghi, S., Borisyak, M., Borsato, M., Boubdir, M., Bowcock, T. J. V., Bozzi, C., Braun, S., Brodski, M., Brodzicka, J., Brossa Gonzalo, A., Brundu, D., Buchanan, E.
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Sprache:eng
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High Energy Physics - Experiment
Physics
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Zusammenfassung: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.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.122.232001