"$a \to \pi^+\pi^-\gamma$ (B meson production)" of "Search for hadronic decays of feebly-interacting particles at NA62"

Number of expected $a \to \pi^+\pi^-\gamma$ events for BR = 1 in the plane (mass, width) after full selection, for production in B meson decays assuming production coupling $C_{bs}/\Lambda=1\,\mathrm{GeV}^{-1}$. Acceptance for particles that reach the FV and decay therein and mass resolution.

在假设产生耦合常数$C_{bs}/Lambda=1,mathrm{GeV}^{-1}$的B介子衰变产生过程中，经过全选择后，分支比（Branching Ratio，BR）=1时，在（质量，宽度）平面上预期的$a o pi^+pi^-gamma$事件数；以及到达有效体积（Fiducial Volume，FV）并在其中衰变的粒子的接受度与质量分辨率。