标题： $ν_μ \to ν_{e}$振荡在CNGS束流中OPERA探测器搜索的最终结果 显示英文标题

标题： Final results of the search for $ν_μ \to ν_{e}$ oscillations with the OPERA detector in the CNGS beam

摘要： OPERA实验在CNGSμ子中微子束中发现了τ中微子的出现，这与3种中微子味振荡假设一致。 OPERA中微子相互作用靶由乳胶云室制成，在电磁簇射的重建方面特别有效。 此外，由于乳胶胶片的极高颗粒度，由电子引起的簇射可以与由$\pi^0$引起的簇射区分开来，从而允许检测电子中微子的带电流相互作用。 本文报告了使用完整数据集搜索电子中微子事件的结果。 采用了一种改进的电子中微子能量估计方法。 数据与3种中微子味混合模型的预期相一致，并用于对引入额外质量本征态$m_{4}$的3+1中微子混合模型的振荡参数设置限制。 在高$\Delta m^{2}_{41}$ $( \gtrsim 0.1~\textrm{eV}^{2})$下，$\sin^2 2\theta_{\mu e}$的上限被设定为0.021（90%置信度），并且在出现模式中，$\Delta m^2_{41} \gtrsim 4 \times 10^{-3}~\textrm{eV}^{2}$被排除在最大混合之外。 显示英文摘要

摘要： The OPERA experiment has discovered the tau neutrino appearance in the CNGS muon neutrino beam, in agreement with the 3 neutrino flavour oscillation hypothesis. The OPERA neutrino interaction target, made of Emulsion Cloud Chamber, was particularly efficient in the reconstruction of electromagnetic showers. Moreover, thanks to the very high granularity of the emulsion films, showers induced by electrons can be distinguished from those induced by $\pi^0$s, thus allowing the detection of charged current interactions of electron neutrinos. In this paper the results of the search for electron neutrino events using the full dataset are reported. An improved method for the electron neutrino energy estimation is exploited. Data are compatible with the 3 neutrino flavour mixing model expectations and are used to set limits on the oscillation parameters of the 3+1 neutrino mixing model, in which an additional mass eigenstate $m_{4}$ is introduced. At high $\Delta m^{2}_{41}$ $( \gtrsim 0.1~\textrm{eV}^{2})$, an upper limit on $\sin^2 2\theta_{\mu e}$ is set to 0.021 at 90% C.L. and $\Delta m^2_{41} \gtrsim 4 \times 10^{-3}~\textrm{eV}^{2}$ is excluded for maximal mixing in appearance mode.