Engineering news
The Large Hadron Collider (LHC) has started delivering physics data as a result of what has been described as a "milestone" collision.
After an almost two-year shutdown and several months of recommissioning, the world's largest particle accelerator is providing collisions to all of its experiments at the unprecedented energy 13 tera-electronvolts (TeV) – almost double the collision energy of its first run.
Protons race around the LHC beam tunnels at three metres per second below the speed of light. The energy released when they collide is used to spark the creation of new particles.
The latest collisions mark the start of season two at Cern's LHC, which is expected to run around the clock for the next three years.
Cern's director-general Rolf Heuer said: "We have provided the basis, now the experiments have to follow. However, don't expect that it will be tomorrow, do not expect that it will be in a month – be patient."
During the first run, the Atlas and Compact Muon Solenoid (CMS) experiments discovered the so-called Higgs boson, an elementary particle that gives other particles mass, which had eluded detection for nearly 50 years. It was the last piece of the puzzle known as the Standard Model – the all-encompassing blueprint of particles and forces in the universe that has been in place since the 1970s.
With the ability to tap into higher energy, the scientists hope to explore realms of ''new physics'' that could yield evidence of hidden extra dimensions and dark matter.
LHC scientists also hope to create more and possibly different strains of Higgs boson, investigate anti-matter, and test the theory of ''supersymmetry'' which predicts that every known particle has a more massive hidden partner.
"The collisions we are seeing today indicate that the work we have done in the past two years to prepare and improve our detector has been successful and marks the beginning of a new era of exploration of the secrets of nature," said CMS spokesman Tiziano Camporesi.
The £3.74 billion LHC, the most powerful atom-smasher ever built, was restarted in April after a two-year upgrade.