Search for the process $e^{+}{e}^{-}\to f_1(1285)$ at the SND detector

Abstract

In the experiment with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider, a search is performed for the direct production of the $C$-even $f_1(1285)$ resonance in $e^{+}{e}^{-}$ collisions. The analysis is based on data with an integrated luminosity of about 200 pb${}^{-1}$, accumulated in the center-of-mass energy range of 1.14--1.46 GeV, of which about 72 pb${}^{-1}$ were recorded near the maximum of the $f_1(1285)$ resonance. The $f_1(1285)$ production cross section at the resonance maximum $\sigma (e^{+}{e}^{-}\to f_1)=(31\pm 13\pm 2)$ pb and the branching fraction $B(f_1(1285)\to e^{+}{e}^{-})=(3.5\pm 1.4\pm 0.3)\times 10^{-9}$ have been measured. The significance of the observation of the $e^{+}{e}^{-}\to f_1(1285)$ process is $2.5\sigma$. Since the significance is low, we also present the upper limits at the 90% confidence level: $σ(e^+e^-\to f_1)<48\mbox{ pb}$ and $B(f_1(1285)\to e^{+}{e}^{-})<5.4\times 10^{-9}$.

15 pages, 5 figures