MARATTO

article · Physical Review Letters

Search for New Phenomena in Two-Body Invariant Mass Distributions Using Unsupervised Machine Learning for Anomaly Detection at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:mrow></mml:math> with the ATLAS Detector

202425 citationsOpen accessMohammed V University

In plain language

Unsupervised anomaly detection techniques can assist in the search for unknown physical phenomena within complex particle collision data. Using 140 inverse femtobarns of proton-proton collision data collected at 13 teraelectronvolts by the ATLAS detector at the Large Hadron Collider, collision events containing at least one electron or muon were analysed. An autoencoder neural network was trained directly on the data, with anomalous event regions identified through the reconstruction loss of the decoder. The analysis examined nine two-body invariant mass distributions consisting of a light jet or b-jet paired with an electron, muon, photon, or a second jet. Across these distributions, the observed data showed no significant deviation from standard background expectations. Consequently, upper limits were established for generic Gaussian resonance signals across various mass widths.

Key takeaways

  • An unsupervised machine learning autoencoder was trained on collision data to identify anomalous events based on reconstruction loss.
  • The evaluation examined proton-proton collisions at 13 teraelectronvolts using 140 inverse femtobarns of data from the ATLAS detector.
  • Nine distinct invariant mass spectra involving pairs of jets, leptons, or photons were assessed for anomalous resonant signals.
  • No statistically significant deviations from expected background distributions were detected in the identified regions.
  • Constraints were established on contributions from generic Gaussian signals across various resonance mass widths.

Why it matters

Exploring particle physics data without predefined signal models allows researchers to detect unexpected phenomena that traditional theory-driven searches might miss. Applying machine learning to sift through massive collision datasets enhances the ability to spot anomalies automatically. While no new physical particles were identified in this instance, establishing clear constraints helps refine future experimental searches and narrows the theoretical parameters for phenomena beyond the Standard Model.

Commercialisation angle

The abstract does not indicate an application pathway, as it describes fundamental research in experimental particle physics.

AI-generated from the published abstract. Always read the original work before citing.

Abstract

Searches for new resonances are performed using an unsupervised anomaly-detection technique. Events with at least one electron or muon are selected from 140 fb^{-1} of pp collisions at sqrt[s]=13 TeV recorded by ATLAS at the Large Hadron Collider. The approach involves training an autoencoder on data, and subsequently defining anomalous regions based on the reconstruction loss of the decoder. Studies focus on nine invariant mass spectra that contain pairs of objects consisting of one light jet or b jet and either one lepton (e,μ), photon, or second light jet or b jet in the anomalous regions. No significant deviations from the background hypotheses are observed. Limits on contributions from generic Gaussian signals with various widths of the resonance mass are obtained for nine invariant masses in the anomalous regions.

Research topics

  • Particle physics theoretical and experimental studies
  • Particle Detector Development and Performance
  • Computational Physics and Python Applications

Read the original research

This page summarises published work. The authoritative version sits with the publisher.

DOI: 10.1103/physrevlett.132.081801

Is something wrong with this record? Report it or request removal.

Discussion

Discuss this research

Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.

No discussion yet. Open the first thread.