CERN ATLAS experiment releases 65 TB of open data for research

The ATLAS Experiment at CERN has made two years of scientific data available to the public for research purposes. The data include recordings of proton-proton collisions from the Large Hadron Collider (LHC) at a collision energy of 13 TeV.

This is the first time ATLAS has released data on this scale and marks a major milestone in the public access to and use of LHC data.

“Open access is a core value of CERN and the ATLAS Collaboration,” says Andreas Hoecker, spokesperson for ATLAS. “Since the beginning, ATLAS has striven to make its results fully accessible and reusable through open access archives such as arXiv and HepData. ATLAS has routinely released open data for educational purposes. Now we are taking it a step further: we are inviting everyone to explore the data that led to our discoveries.”

ATLAS has released all the data collected by the experiment during the LHC’s proton-proton operation in 2015 and 2016 under the Creative Commons CC0 exemption. This amounts to around 65 TB of data, representing more than 7 billion LHC collisions.

In addition, ATLAS has released 2 billion events of simulated “Monte Carlo” data, which are essential for performing a physics analysis.

External researchers are especially encouraged to explore ATLAS’s open data. “In addition to the data, we’ve provided extensive documentation on several of our analyses, walking users through our process step by step,” said Zach Marshall, ATLAS Computing co-coordinator.

“These guides provide first-hand experience of working on a real ATLAS result, allowing anyone to test our tools and assess the systematic uncertainties associated with the result for themselves.”

ATLAS traditionally collaborates with non-ATLAS scientists through short-term partnerships, giving them full access to ATLAS data, internal tools and information. Through open data, ATLAS researchers hope to further nurture this dialogue and collaboration.

“In particular,” Zach adds, “we want to encourage phenomenologists and computer scientists to explore our datasets, rather than relying on mock-ups.”

Today’s release builds on previous open data releases for educational use (in 2016 and 2020). “All of our open data releases are now available via the ATLAS open data website,” said Dilia Portillo, ATLAS Outreach and Education co-coordinator.

“The website contains multi-level documentation, video tutorials and online tools aimed at the full spectrum of users, from high school students to senior particle physics researchers. In addition, the software used to create the open data for educational use has been released.

“This provides a seamless transition from the open research data to all the outreach and education tutorials, including the recently updated documentation on the Higgs boson discovery. With a little time and dedication, you can go from being a relative novice to doing your own analysis.”

The ATLAS open data website also serves as a hub for the community, which includes teachers, students, enthusiasts, and now scientists. Anyone who is interested in the open data can also get in touch directly with ATLAS physicists, who are available to respond to user feedback and make suggestions.

This release marks the beginning of more to come, with ATLAS’ first release of lead-lead-nucleus collision data next. The ATLAS Collaboration, along with the other main LHC experiment collaborations, has committed to making all of its data publicly available over time. Openness is deeply ingrained in the culture of high-energy physics, ensuring greater accessibility, reproducibility and better science.