Precision measurement of the matrix elements for η →π+π-π0 and η →π0π0π0 decays


Ablikim M., Achasov M., Adlarson P., Aliberti R., Amoroso A., An M., ...More

Physical Review D, vol.107, no.9, 2023 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 107 Issue: 9
  • Publication Date: 2023
  • Doi Number: 10.1103/physrevd.107.092007
  • Journal Name: Physical Review D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, INSPEC, zbMATH
  • Istanbul University Affiliated: Yes

Abstract

A precision measurement of the matrix elements for η→π+π-π0 and η→π0π0π0 decays is performed using a sample of (10087±44)×106 J/ψ decays collected with the BESIII detector. The decay J/ψ→γη is used to select clean samples of 631,686 η→π+π-π0 decays and 272,322 η→π0π0π0 decays. The matrix elements for both channels are in reasonable agreement with previous measurements. The nonzero gX2Y term for the decay mode η→π+π-π0 is confirmed, as reported by the KLOE Collaboration, while the other higher-order terms are found to be insignificant. Dalitz plot asymmetries in the η→π+π-π0 decay are also explored and are found to be consistent with charge conjugation invariance. In addition, a cusp effect is investigated in the η→π0π0π0 decay, and no obvious structure around the π+π- mass threshold is observed.