MCPLOTS: a particle physics resource based on volunteer computing

TL;DR

MCPLOTS is a public, continuously updated repository of plots comparing high-energy-physics event generators to experimental data using HEPDATA and Rivet, powered by volunteer computing via LHC@home 2.0. The paper details the system's architecture, data formats, and workflow for adding analyses and generators, including data submission, validation, and histogram merging. It also covers processes for updating the site with new generator versions, tunes, and events, along with the Test4Theory virtualization framework that enables large-scale simulations. Collectively, the work provides a practical, reproducible platform for MC validation and tuning, with mechanisms for community participation and future enhancements such as pre-release validation and citizen-science apps.

Abstract

The mcplots.cern.ch web site (MCPLOTS) provides a simple online repository of plots made with high-energy-physics event generators, comparing them to a wide variety of experimental data. The repository is based on the HEPDATA online database of experimental results and on the RIVET Monte Carlo analysis tool. The repository is continually updated and relies on computing power donated by volunteers, via the LHC@HOME platform.

Figures (12)

• Figure 1: The main mcplots menu.
• Figure 2: The analysis filter submenu; normal view (left) and after clicking on the Specific Analysis dropdown menu (right).
• Figure 3: Illustrations of the process and observables list; normal view (left) and after clicking on a shaded dropdown menu (right), in this case Identified Particles: Y.
• Figure 4: The plot page. The generator and tune group selections are at the top, followed by the available plots for the chosen observable, ordered by CM energy and subordered alphabetically.
• Figure 5: The ratio pane, before (a) and after (b) clicking on the show details link. The example corresponds to the left-hand plot shown in figure \ref{['fig:plotPage']}.