Observation of Orbitally Excited $B_c^+$ States
Year: 2025
Type: article
Abstract: The observation of a wide peaking structure in the B c + γ mass spectrum is reported using proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb − 1 . The statistical significance over the background-only hypothesis exceeds seven standard deviations. The width of the observed structure is larger than the expectation from a single-peak hypothesis, and is well described by an effective minimal model consisting of two narrow peaks located at 6704.8 ± 5.5 ± 2.8 ± 0.3 MeV / c 2 and 6752.4 ± 9.5 ± 3.1 ± 0.3 MeV / c 2 . The uncertainty terms are statistical, systematic, and associated to the knowledge of the B c + mass, respectively. The measured peak locations are in line with theoretical predictions for lowest excited P -wave B c + states, marking the first observation of orbitally excited beauty-charm mesons and providing important insights into the internal dynamics of hadrons containing two heavy quarks.
DOI: 10.5167/uzh-282991
Authors: Aaij, R., Abdelmotteleb, A. S. W., Abellan Beteta, C., Abudinén, F., Ackernley, T., Adefisoye, A. A., Adeva, B., Adinolfi, M., Adlarson, P., Agapopoulou, C., Aidala, C. A., Ajaltouni, Z., Akar, S., Akiba, K., Albicocco, P., Albrecht, J., Alessio, F., Aliouche, Z., Alvarez Cartelle, P., Amalric, R., Amato, S., Amey, J. L., Amhis, Y., An, L., Anderlini, L., Andersson, M., Andreola, P., Andreotti, M., Andres Estrada, S., LHCb Collaboration, et al
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7124766999
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