Measuring Charged Particle Multiplicity with Early ATLAS Public Data

TL;DR

This paper analyzes publicly available early LHC collision images to measure charged particle multiplicity and distributions, employing image processing techniques to extract meaningful physics data from low-resolution images.

Contribution

It introduces two image processing methods for extracting particle data from public LHC images, demonstrating their effectiveness in physics analysis.

Findings

Distributions agree with existing literature

Two processing methods yield consistent results

Validates public data for physics research

Abstract

We study 100 images of early LHC collisions that were recorded by the ATLAS experiment and made public for outreach purposes, and extract the charged particle multiplicity as a function of momentum for proton-proton collisions at sqrt(s) = 7 TeV. As the collisions we study have already been pre-processed by the ATLAS Collaboration, the tracks are visible, but are available to the public only in the form of low-resolution bitmaps. We employ two separate image processing methods, one based on the industry-standard OpenCV library and C++, another based on self-developed algorithms in Python. We present the transverse momentum and azimuthal angle distributions of the particles obtained through both methods, in agreement with the literature.