Using data samples with a total integrated luminosity of approximately 18 fb−1 collected by the BESIII detector operating at the Beijing Electron-Positron Collider II, the process e+e− →ΛΛ ̄η is studied at center-of-mass energies between 3.5106 and 4.6988 GeV. The Born cross section for the process e+e− → ΛΛ ̄η is measured. No significant structure is observed in the Born cross section line shape. An enhancement near the ΛΛ ̄ mass threshold is observed for the first time in the process. The structure can be described by an S-wave Breit-Wigner function. Neglecting contribution of excited Λ states and potential interferences, the mass and width are determined to be (2356 pm 7 pm 15) MeV/c2 and (304 pm 28 pm 54) MeV, respectively, where the first uncertainties are statistical and the second are systematic
Measurement of e+e−→ΛΛ¯η from 3.5106 to 4.6988 GeV and study of ΛΛ¯ mass threshold enhancement
Garzia, I.;Scodeggio, M.;
2023
Abstract
Using data samples with a total integrated luminosity of approximately 18 fb−1 collected by the BESIII detector operating at the Beijing Electron-Positron Collider II, the process e+e− →ΛΛ ̄η is studied at center-of-mass energies between 3.5106 and 4.6988 GeV. The Born cross section for the process e+e− → ΛΛ ̄η is measured. No significant structure is observed in the Born cross section line shape. An enhancement near the ΛΛ ̄ mass threshold is observed for the first time in the process. The structure can be described by an S-wave Breit-Wigner function. Neglecting contribution of excited Λ states and potential interferences, the mass and width are determined to be (2356 pm 7 pm 15) MeV/c2 and (304 pm 28 pm 54) MeV, respectively, where the first uncertainties are statistical and the second are systematicI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.