Measurement of the Cross Section for e+e- → Ξ- Ξ ̄ + and Observation of an Excited Ξ Baryon


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Ablikim M., Achasov M., Adlarson P., Ahmed S., Albrecht M., Alekseev M., ...More

Physical Review Letters, vol.124, no.3, 2020 (SCI-Expanded) identifier identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 124 Issue: 3
  • Publication Date: 2020
  • Doi Number: 10.1103/physrevlett.124.032002
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, EMBASE, INSPEC, MEDLINE, zbMATH, DIALNET
  • Ankara University Affiliated: Yes

Abstract

© 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.Using a total of 11.0 fb-1 of e+e- collision data with center-of-mass energies between 4.009 and 4.6 GeV and collected with the BESIII detector at BEPCII, we measure fifteen exclusive cross sections and effective form factors for the process e+e-→Ξ-Ξ̄+ by means of a single baryon-tag method. After performing a fit to the dressed cross section of e+e-→Ξ-Ξ̄+, no significant ψ(4230) or ψ(4260) resonance is observed in the Ξ-Ξ̄+ final states, and upper limits at the 90% confidence level on ΓeeB for the processes ψ(4230)/ψ(4260)→Ξ-Ξ̄+ are determined. In addition, an excited Ξ baryon at 1820 MeV/c2 is observed with a statistical significance of 6.2-6.5σ by including the systematic uncertainty, and the mass and width are measured to be M=(1825.5±4.7±4.7) MeV/c2 and Γ=(17.0±15.0±7.9) MeV, which confirms the existence of the JP=32- state Ξ(1820).