Displaced vertex in LHCb
The LHCb experiment measures B mesons. Their decays might yield clues about what happened after the Big Bang that allowed antimatter to all but disappear and matter to build our universe. In this first reconstructed LHCb B event, the collision of two protons at the primary vertex yields many particles (in black), including a B^+ meson (in yellow), which travels a distance--you can measure it!--before it decays into other particles at the B decay vertex. The tracks have been adjusted to make the Primary vertex clearer to the observer.