A precision measurement of the matrix elements for η → π+π−π0 and η → π0π0π0 decays is performed using a sample of (10087 pm 44) × 10^6 J/ψ decays collected with the BESIII detector. The decay J/ψ → γη is used to select clean samples of 631686 η → π+π−π0 decays and 272322 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 πþπ− mass threshold is observed.
Precision measurement of the matrix elements for η→π+π−π0 and η→π0π0π0 decays
Garzia I.;Scodeggio M.;
2023
Abstract
A precision measurement of the matrix elements for η → π+π−π0 and η → π0π0π0 decays is performed using a sample of (10087 pm 44) × 10^6 J/ψ decays collected with the BESIII detector. The decay J/ψ → γη is used to select clean samples of 631686 η → π+π−π0 decays and 272322 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 πþπ− mass threshold is observed.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
