Noot in Circle
All research

Ongoing · Cambridge / ATLAS

Reconstructing displaced decays

What if a particle travelled far enough to decay somewhere other than the original collision point?

An illustrated walkthrough

Where did it decay?

Follow a hypothetical particle from the original collision, then work backwards from the signals its decay leaves in the detector.

Detector cross-section Illustrative · Not to scale
Schematic of a displaced decay in a detector A particle travels outward from the original collision. Short track segments from its decay appear in outer detector layers and are projected back toward a candidate decay point.

Reconstruction stages

In this example, a long-lived particle travels away from the original collision before decaying. Extending the short outer track segments back towards each other gives a candidate location for the decay.

What I’m investigating

Some proposed long-lived particles could travel into the outer layers of a detector before decaying. The place they decay is called a displaced vertex. To reconstruct it, we work backwards from the traces left by the decay products.

My MPhil project with Professor Oleg Brandt explores whether machine learning can help associate short reconstructed track segments with a common decay point in the ATLAS muon spectrometer. The work is at the investigation stage.

Further reading

From the physics to the project

Read the ATLAS explainer Read my original MPhil introduction