8โ€“12 Sept 2025
Hamburg, Germany
Europe/Berlin timezone

Deep Learning for Primary Vertex Identification in the ATLAS Experiment

11 Sept 2025, 15:50
20m
ESA B

ESA B

Oral Track 2: Data Analysis - Algorithms and Tools Track 2: Data Analysis - Algorithms and Tools

Speakers

Qi Bin Lei (Stanford University (US)) Rocky Bala Garg (Stanford University (US))

Description

The exponential time scaling of traditional primary vertex reconstruction algorithms raises significant performance concerns for future high-pileup environments, particularly with the upcoming High Luminosity upgrade to the Large Hadron Collider. In this talk, we introduce PV-Finder, a deep learning-based approach that leverages reconstructed track parameters to directly predict primary vertex positions and track-to-vertex associations. Primary Vertex identification is achieved using a multi-layer perceptron (MLP) that converts track data into one-dimensional probability distributions, known as kernel density estimations (KDEs). These KDEs then serve as inputs to a convolutional neural network (CNN), specifically utilizing UNet and UNet++ architectures, to refine vertex position predictions. More recently, we have also explored the integration of graph neural networks (GNNs) to enhance track-vertex association. Preliminary results demonstrate that PV-Finder offers improved vertex reconstruction efficiency and accuracy, making it a compelling alternative to traditional methods.

Significance

This presentation introduces novel algorithmic development in the form of PV-Finder, a new deep learning-based framework for primary vertex reconstruction, tailored for the challenges of high-pileup environments expected at the HL-LHC. Rather than simply reporting on existing approaches, it presents a new methodology that replaces traditional, computationally intensive vertexing algorithms with a machine learning pipeline. The preliminary results suggest clear performance improvements in both efficiency and accuracy over existing techniques, which is essential for scaling to HL-LHC conditions. These advancements represent a substantial step forward in applying modern ML techniques to solve a core reconstruction problem in high-energy physics.

Experiment context, if any ATLAS, CMS

Author

Qi Bin Lei (Stanford University (US))

Co-author

Rocky Bala Garg (Stanford University (US))

Presentation materials