The first direct measurement of the absolute branching fraction of Σ+ → Λe+νe is reported based on an e+e− annihilation sample of (10087 pm 44) Jpsi events collected with the BESIII detector at sqrt(s)=3.097 GeV. The branching fraction is determined to be B(Σ → Λe+ νe) = (2.93 pm 0.74stat pm 0.13syst) x 10^(-5), which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average B(Σ−→Λe−ν ̄e) of BðΣ → Λe ν ̄eÞ and the lifetimes of Σ+ , the ratio is determined to be 1.06 pm 0.28, which is within 1.8 standard deviations of the value expected in the absence of second-class currents.
First direct measurement of the absolute branching fraction of Σ+→Λe+νe
Garzia, I.;Scodeggio, M.;
2023
Abstract
The first direct measurement of the absolute branching fraction of Σ+ → Λe+νe is reported based on an e+e− annihilation sample of (10087 pm 44) Jpsi events collected with the BESIII detector at sqrt(s)=3.097 GeV. The branching fraction is determined to be B(Σ → Λe+ νe) = (2.93 pm 0.74stat pm 0.13syst) x 10^(-5), which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average B(Σ−→Λe−ν ̄e) of BðΣ → Λe ν ̄eÞ and the lifetimes of Σ+ , the ratio is determined to be 1.06 pm 0.28, which is within 1.8 standard deviations of the value expected in the absence of second-class currents.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.