Observation of a New Excited Beauty Strange Baryon Decaying to Ξb− π+π−
Name
PhysRevLett.126.252003.pdf
Description
Published version
Size
621.6 KB
Format
Adobe PDF
Checksum (MD5)
bb70ca8c76f7d10afd66c5edebda2e90
Author(s)
Harris, Philip
Date Issued
2021
Journal
Physical Review Letters
Publisher
American Physical Society (APS)
Citation
Harris, Philip. 2021. "Observation of a New Excited Beauty Strange Baryon Decaying to Ξb− π+π−." Physical Review Letters, 126 (25).
Version
Final published version
Abstract
The Ξ_{b}^{-}π^{+}π^{-} invariant mass spectrum is investigated with an event sample of proton-proton collisions at sqrt[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^{-}.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1103/PHYSREVLETT.126.252003
