Электронный каталог

Статья

Ablikim, M.
Observation of J/*q Decays to e*+e*-e*+e*- and e*+e*-*m*+*m*- / M.Ablikim, O.Bakina, I.Boyko, G.Chelkov, D.Dedovich, I.Denysenko, A.Guskov, Y.Nefedov, A.Sarantsev, A.Zhemchugov, [a.o.] // Physical Review D [Electronic resource]. – 2024. – Vol. 109, No. 5. – P. 052006. – URL: https://doi.org/10.1103/PhysRevD.109.052006. – Bibliogr.: 35.

Using a data sample of 4.481 × 10 8 ψ(3686) events collected with the BESIII detector, we report the first observation of the four-lepton-decays J=ψ → eþe−eþe− and J=ψ → eþe−μþμ− utilizing the process ψ(3686) → πþπ−J=ψ. The branching fractions are determined to be [5.48 *( 0.31(stat) *(0.45(syst)]× 10−5 and [3.53 *( 0.22(stat) *( 0.13(syst)] × 10−5, respectively. The results are consistent with theoretical predictions. No significant signal is observed for J=ψ → μþμ−μþμ−, and an upper limit on the branching fraction is set at 1.6 × 10−6 at the 90% confidence level. A CP asymmetry observable is constructed for the first two channels, which is measured to be (−0.012 *( 0.054 *( 0.010) and (0.062 *( 0.059 *( 0.006), respectively. No evidence for CP violation is observed in this process.



ОИЯИ = ОИЯИ (JINR)2024
Спец.(статьи,препринты) = С 332.7 - Встречные е+е- и мю+мю- пучки