发表机构
School of Physics and Mechanical and Electrical Engineering, Longyan University（龙岩学院物理与机电工程学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过比较两种产生模型并分析NA62实验数据，证明暗光子搜索中产生形状效应不可忽略，提出投影准则作为速率因子化的定量检验方法。
AI 中文摘要
长寿命粒子搜索中的产生模型不确定性既会影响包含产额，也会影响实验接收度所采样的运动学分布。我们通过将修正的Weizsäcker--Williams描述与有效准实近似在共同物理域上归一化后进行比较，来隔离后者对质子轫致辐射产生暗光子的效应。在该域内固定产生产额时，由此产生的接收度差异直接衡量了速率因子化的偏离程度。在NA62束流倾倒几何结构中，中心计算在显示的NA62灵敏度重叠区域内的每个数值收敛网格点上都给出了分数接收度偏移$\delta_{\rm NF}>0.3$。该结论在有效QRA离壳标度为1.0、1.5和2.0 GeV以及所考虑的孔径变化下均成立。另外，公开的NA62全选择接收度给出了Mixing和Bremsstrahlung产生类别之间非恒定的双缪子接收度比率，范围约为0.58至4.23，在分析的HEPData网格上，与1的中值绝对偏差约为0.79。这提供了补充证据，表明已发表的全选择接收度依赖于产生类别。更一般地，投影准则提供了速率因子化的定量检验。归一化的产生形状变化在所需精度下必须对接收度响应具有可忽略的投影。当此条件不满足时，产生模型依赖性必须通过接收度计算传播，或作为接收度不确定性处理。
英文摘要
Production model uncertainties in long-lived particle searches can affect both the inclusive yield and the kinematic distributions sampled by the experimental acceptance. We isolate the latter effect by comparing the modified Weizsäcker--Williams description with the effective quasireal approximation for dark photon production via proton bremsstrahlung after normalizing both spectra on a common physical domain. At fixed production yield within this domain, the resulting acceptance difference directly measures the departure from rate factorization. In the NA62 beam dump geometry, the central calculation gives a fractional acceptance shift $δ_{\rm NF}>0.3$ at every numerically converged grid point within the displayed NA62 sensitivity overlap. This conclusion persists for effective QRA off-shell scales of 1.0, 1.5, and 2.0~GeV and under the aperture variations considered. Separately, the public NA62 full selection acceptances give a nonconstant dimuon acceptance ratio between the Mixing and Bremsstrahlung production categories, ranging from approximately 0.58 to 4.23, with a median absolute departure from unity of approximately 0.79 over the analyzed HEPData grid. This provides complementary evidence that the published full selection acceptance depends on the production category. More generally, the projection criterion provides a quantitative test of rate factorization. The normalized production shape variation must have negligible projection onto the acceptance response at the required accuracy. When this condition is not satisfied, production model dependence must be propagated through the acceptance calculation or treated as an acceptance uncertainty.
