Research at the Large Hadron Collider, a vast particle-physics project in Europe that scientists hope will answer fundamental questions about the universe, will be delayed at least two months after an accident during start-up procedures this week that resulted in a large leak of helium, according to a statement released today by the European Center for Nuclear Research, or CERN, which is operating the experiment.

No one was injured in the incident, but the statement said an electrical connection between two magnets was likely to have melted. That failure allowed helium to leak into a race-track-like tunnel in which protons will be accelerated to high speeds and then crashed into one another. Physicists, including some working from the United States, hope the resulting shower of particles will help answer complex questions involving extra dimensions, unseen “dark” matter, and how particles obtain their mass, among other things.

Keeping the magnets chilled with helium to just above absolute zero is key to the operation of the collider. The helium leak means that a part of the tunnel will need to be warmed up in order to make repairs, then cooled down once again. —Andrew Mytelka