AI 中文总结
本研究利用VEPP-2000对撞机的CMD-3探测器，通过分析质心系能量1.20-1.36GeV的扫描数据及共振峰数据，获得$e^+ e^-\to f_1(1285)$反应产生C偶宇称共振的4.5σ证据，测得相关截面与衰变分支比。
AI 中文摘要
本研究利用VEPP-2000对撞机上的CMD-3探测器对$e^+ e^-\to f_1(1285)$反应进行寻找，使用质心系能量范围$E_{c.m.}=1.20$至$1.36$GeV的扫描数据，积分亮度为$109.1$pb$^{-1}$；在$f_1(1285)$共振峰能量$E_{c.m.}=1282$MeV处专门采集了$51.7$pb$^{-1}$的数据，在该能量下通过$e^+ e^-\to\pi^0\rho^0$反应共发现$26.5\rd\bar{7}.4$个事例，扫描数据中未观测到信号迹象。研究将结果解释为在$e^+ e^-\to f_1(1285)\to\rho^0\rho^0$反应中通过双光子相互作用产生C偶宇称共振的$4.5\rd\bar{\text{σ}}$证据，测得产生截面$\rd\bar{\text{σ}}(e^+ e^-\to f_1)=0.074\rd\bar{\text{±}}0.021\rd\bar{\text{±}}0.010$nb，$f_1(1285)$对$e^+ e^-$对的衰变分支比$B(f_1(1285)\to e^+ e^-)=(8.3\rd\bar{\text{±}}2.3\rd\bar{\text{±}}1.1)\times10^{-9}$。
英文摘要
A search for the $e^+ e^-\to f_1(1285)$ reaction is performed with the CMD-3 detector at the VEPP-2000 collider. Data from a scan in the center-of-mass energy range Ec.m.=1.20--1.36 GeV with 109.1 pb$^{-1}$ of the integrated luminosity is used. A dedicated 51.7 pb$^{-1}$ have been collected at the $f_1(1285)$ resonance peak energy Ec.m.=1282 MeV, where $26.5 \pm 7.4$ events have been found in the $e^+ e^-\toηπ^0π^0$ reaction. No indication of the signal is observed in the scan data. We interpret the result as 4.5$σ$ evidence of the C-even resonance production in the $e^+ e^-\to f_1(1285)\toηπ^0π^0$ reaction via the two-photon interaction. The production cross section is found to be $σ(e^+ e^-\to f_1) = 0.074 \pm 0.021 \pm 0.010$ nb, and the corresponding branching fraction to the $e^+ e^-$ pair is $B(f_1(1285)\to e^+e^-) = (8.3 \pm 2.3 \pm 1.1)\times 10^{-9}$.
Comments4 pages, 4 figures
