Unexplainable phenomenon observed at Tevatron

''The team was in for a big surprise. First, they saw far more muons coming from the collisions than expected. But crucially, some of these muons seemed to have been created outside of the beam pipe: they had left no trace in the innermost layer of the detector.

The CDF team says it is unable to explain such muons using the standard model of particle physics, or from what they know of their detector.'' [source]