"$a \to e^+e^-$ (mixing with $\eta$)" of "Search for hadronic decays of feebly-interacting particles at NA62"

Number of expected $a \to e^+e^-$ events for BR = 1 in the plane (mass, width) after full selection, for production in mixing with $\eta$ assuming production coupling $\theta_{\eta} = 1$. Acceptance for particles that reach the FV and decay therein and mass resolution.

在与η介子混合产生且假设产生耦合角$ heta_{eta}=1$的前提下，经过完整筛选后，分支比（Branching Ratio，BR）为1时，在（质量，宽度）平面内预期的$a o e^+e^-$（粒子$a$衰变为电子-正电子对）事件数，以及到达 fiducial体积（Fiducial Volume，FV）并在其中衰变的粒子接收度与质量分辨率。