Scientists say they believe they have captured the elusive Higgs Boson particle that gives matter mass.
Professor John Womersley, chief executive of the Science and Technology Facilities Council, told reporters at a London briefing that they had discovered a particle consistent with the Higgs Boson.
Discovery is the important word. That is confirmed. It's a momentous day for science.
There is a strong Welsh connection to the groundbreaking scientific project as Dr Lyn Evans from Aberdare was the project leader.
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Welsh Labour members will meet later today in Ammanford for the launch of the party's general election campaign.
Welsh employers are being urged to offer more work placements to young people after a study found experience to be the most valued asset.
A bright start, especially for eastern Wales, before cloud thickens from the west. Rain and strong winds will then spread eastwards.