Observation of a new excited beauty strange baryon decaying to Ξb- π+π-
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Type :
Article
Publication Status :
Published
Access :
restrictedAccess
https://creativecommons.org/licenses/by/4.0/
https://creativecommons.org/licenses/by/4.0/
Abstract
The Ξb-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 Ξb- is reconstructed via its decays to J/ψΞ- and J/ψΛK-. A narrow resonance, labeled Ξb(6100)-, is observed at a Ξb-π+π- invariant mass of 6100.3±0.2(stat)±0.1(syst)±0.6(Ξb-) MeV, where the last uncertainty reflects the precision of the Ξb- baryon mass. The upper limit on the Ξb(6100)- natural width is determined to be 1.9 MeV at 95% confidence level. The low Ξb(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 Ξc baryon states, the new Ξb(6100)- resonance and its decay sequence are consistent with the orbitally excited Ξb- baryon, with spin and parity quantum numbers JP=3/2-.
Source :
Physical Review Letters
Date :
2021-06-25
Volume :
126
Issue :
25
Publisher :
American Physical Society
URI
http://hdl.handle.net/10679/8233https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.252003
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