arXiv:2608.13652cs.LGhep-ex2026-08被引 1

用对比学习让对撞机异常检测结果可解释,还能精准定位新物理信号。

Contrastive Learning for Interpretable Anomaly Detection at Collider Experiments

论文配图:Contrastive Learning for Interpretable Anomaly Detection at Collider Experiments
图 1 · 摘自论文原文
  • 先用对比学习构建多过程融合的嵌入空间,再用自编码器生成异常得分。
  • 在高亮度LHC模拟数据上,对新物理信号的灵敏度显著提升。
  • 异常事件能反推其最像的已知过程,适合需要可解释性的新物理搜索。

对撞机物理中的通用事件级异常检测面临两大挑战:异常评分难以解释,且与能量尺度和粒子数量强相关。我们提出ORCA框架,分两阶段进行:首先通过跨多种物理过程的监督对比学习构建嵌入空间,然后在该空间中运行标准自编码器生成事件级异常分数。在符合高亮度大型强子对撞机条件的模拟数据上,相比基线自编码器架构,ORCA在新物理信号的广度与深度灵敏度上均有显著提升。更重要的是,对比学习得到的嵌入空间使异常样本具备可解释性:由于已知过程在空间中占据不同区域,可通过最大似然模板拟合将异常事件归因于特定模板过程,并量化不确定性。我们验证了该方法能准确恢复注入的信号产率,包括未参与嵌入训练的信号;对于模板库中不存在的信号,也能通过其最相似的已知过程进行表征。这些结果表明,ORCA为对撞机上的可解释异常检测提供了新路径,嵌入空间所承载的高维物理信息优于传统一维输出拟合,显著增强下游统计分析能力。

原文摘要 · Abstract (English)

Generic event-level anomaly detection for collider physics has two recurring problems: anomaly scores are hard to interpret, and they correlate strongly with energy scale and object multiplicity. We present Organized Representation via Contrastive learning for Anomaly detection (ORCA), a two-stage framework that first learns an embedding space via supervised contrastive learning across a diverse set of physics processes, then runs a standard autoencoder in that space to generate event-level anomaly scores. On a simulated dataset consistent with conditions at the High-Luminosity Large Hadron Collider, ORCA delivers significant gains in both breadth and depth of sensitivity to new physics signals with respect to a baseline autoencoder architecture. Beyond improved sensitivity, the contrastive embedding makes the anomalous sample interpretable: because known processes occupy distinct regions of the space, a maximum-likelihood template fit to the embedding distributions can attribute events in an anomalous sample to template physics processes with quantified uncertainties. We demonstrate that the fit accurately recovers injected signal yields, including for signals excluded from the training of the embedding, and characterizes signals absent from the template library through the known processes they most resemble. These results establish ORCA as a route to interpretable anomaly detection-based searches at colliders, where the embedding geometry carries higher dimensional physics information compared to standard one-dimensional output fits, enhancing downstream statistical analysis.

异常检测对撞机可解释性对比学习

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