New improved Large Hadron Collider clatters back

The world's most powerful particle accelerator, the Large Hadron Collider, has resumed full operations after a two-year upgrade.

Scientists at the underground Cern complex, near Geneva on the border between France and Switzerland, are waiting for the first new data to emerge.

BBC World TV asked Cern physicist Claire Lee in the control room what were the chances of a breakthrough in our understanding of dark matter.