A search for direct production of the f1(1285) resonance in e+e− annihilation is performed with the SND detector at the VEPP-2000 e+e− collider. The analysis is based on data with an integrated luminosity of 15.1 pb−1 accumulated in the center-of-mass energy range 1.2–1.4 GeV. Two e+e−→f1(1285) candidate events are found at the peak of the resonance and zero events beyond the resonance. The significance of the e+e−→f1(1285) signal is 2.5σ. The cross section at the maximum of the resonance is found to be σ(e+e−→f1)=45−24 +33 pb. The corresponding branching fraction B(f1(1285)→e+e−)=(5.1−2.7 +3.7)×10−9. We consider this result as a first indication of the process e+e−→f1(1285). The measured branching fraction is consistent with the theoretical prediction.
|Журнал||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Состояние||Опубликовано - 10 янв 2020|