Observation of a new excited beauty strange baryon decaying to Ξ&lt;em&gt;b&lt;/em&gt;&lt;sup&gt;-&lt;/sup&gt;&lt;em&gt;π&lt;/em&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;em&gt;π&lt;/em&gt;&lt;sup&gt;-&lt;/sup&gt;

Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Escalante Del Valle, A.; Frühwirth, R.; Jeitler, M.; Caminada, L.; Ebrahimi, A.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H.C.; Kotlinski, D.; Langenegger, U.; Missiroli, M.; Rohe, T.; Vetens, W.

doi:10.1103/PhysRevLett.126.252003

Observation of a new excited beauty strange baryon decaying to Ξb^-π⁺π^-

Sirunyan AM, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Dragicevic M, Escalante Del Valle A, Frühwirth R, Jeitler M, Caminada L, Ebrahimi A, Erdmann W, Horisberger R, Ingram Q, Kaestli HC, Kotlinski D, Langenegger U, Missiroli M, Rohe T, Vetens W, et al.

Citation

Sirunyan, A. M., Tumasyan, A., Adam, W., Andrejkovic, J. W., Bergauer, T., Chatterjee, S., … Vetens, W. (2021). Observation of a new excited beauty strange baryon decaying to Ξb^-π⁺π^-. Physical Review Letters, 126(25), 252003 (19 pp.). https://doi.org/10.1103/PhysRevLett.126.252003

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:39364

The Ξ_b^-π⁺π^- invariant mass spectrum is investigated with an event sample of proton-proton collisions at √s = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb^-1. The ground state Ξ_b^- is reconstructed via its decays to J/ψΞ^- and J/ψΛK^-. A narrow resonance, labeled Ξ_b(6100)^-, is observed at a Ξ_b^-π⁺π^- invariant mass of 6100.3 ± 0.2(stat) ± 0.1(syst) ± 0.6(Ξ_b^-) MeV, where the last uncertainty reflects the precision of the Ξ_b^- baryon mass. The upper limit on the Ξ_b(6100)^- natural width is determined to be 1.9 MeV at 95% confidence level. The low Ξ_b(6100)^- signal yield observed in data does not allow a measurement of the quantum numbers of the new state. However, following analogies with the established excited Ξ_c baryon states, the new Ξ_b(6100)^- resonance and its decay sequence are consistent with the orbitally excited Ξ_b^- baryon, with spin and parity quantum numbers J^P = 3/2^-.