Observation of a Narrow Pentaquark State, P c ( 4312 ) + , and of the Two-Peak Structure of the P c ( 4450 )

• Published in: Physical review letters 2019-06, Vol.122 (22), Article 222001
• Main Authors: 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., Belavin, V., Belin, S., Beliy, N., Bellee, V., Belloli, N., Belous, K., Belyaev, I., 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., Brea Rodriguez, A., Brodski, M., Brodzicka, J.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.122.222001

A narrow pentaquark state, Pc(4312)+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λb0→J/ψpK- decays, which is an order of magnitude larger than that previously analyzed by the LHCb Collaboration. The Pc(4450)+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, Pc(4440)+ and Pc(4457)+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σc+D¯0 and Σc+D¯*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.