One of the important goals of the proposed future \(\hbox {e}^{+}\hbox {e}^{-}\) collider experiments is the search for dark matter particles using different experimental approaches. The most general search approach is based on the mono-photon signature, which is expected when production of the invisible final state is accompanied by a hard photon from initial state radiation. Analysis of the energy spectrum and angular distributions of those photons can shed light on the nature of dark matter and its interactions. Therefore, it is crucial to be able to simulate the signal and background samples in a uniform framework, to avoid possible systematic biases. The Whizard program is a flexible tool, which is widely used by \(\hbox {e}^{+}\hbox {e}^{-}\) collaborations for simulation of many different “new physics” scenarios. We propose the procedure of merging the matrix element calculations with the lepton ISR structure function implemented in Whizard. It allows us to reliably simulate the mono-photon events, including the two main Standard Model background processes: radiative neutrino pair production and radiative Bhabha scattering. We demonstrate that cross sections and kinematic distributions of mono-photon in neutrino pair-production events agree with corresponding predictions of the \(\mathcal{KK}\) MC, a Monte Carlo generator providing perturbative predictions for SM and QED processes, which has been widely used in the analysis of LEP data.

拟议的未来\（\ hbox {e} ^ {+} \ hbox {e} ^ {-} \）对撞机实验的重要目标之一是使用不同的实验方法寻找暗物质粒子。最普遍的搜索方法是基于单光子签名，当不可见最终状态的产生伴随着初始状态辐射产生的硬光子时，可以预期到这种情况。对这些光子的能谱和角分布进行分析可以使人们了解暗物质的性质及其相互作用。因此，至关重要的是能够在一个统一的框架中模拟信号和背景样本，以避免可能的系统偏差。该Whizard程序是一个灵活的工具，它被广泛应用于通过\（\ hbox中{E} ^ {+} \ hbox中{E} ^ { - } \）协作以模拟许多不同的“新物理学”场景。我们提出了将矩阵元素计算与Whizard中实现的轻子ISR结构函数合并的步骤。它使我们能够可靠地模拟单光子事件，包括两个主要的标准模型背景过程：辐射中微子对的产生和辐射Bhabha散射。我们证明中微子对产生事件中单光子的横截面和运动分布与\（\ mathcal {KK} \）  MC的对应预测相符，MC为蒙特卡罗发生器，提供了SM和QED过程的扰动预测，具有被广泛用于LEP数据分析。