Large Hadron Collider short fixed

Geneva - Cern engineers said on Tuesday they have resolved a problem that had delayed the relaunch after a two-year refit of the Large Hadron Collider particle smasher, which is probing the mysteries of the universe.

A statement from the research centre just outside Geneva said a metal fragment that caused an intermittent short circuit in one of the giant magnets in the vast underground complex had been successfully removed.

The relaunch of the so-called 'Big Bang' machine had to be postponed last week because of the problem.

Cern said that after new tests on all the circuits in the area where the fault appeared, the way would be clear for proton particles to be sent in opposite directions right around the machine's 27-km underground tubes.

This could happen "in a few days", the statement said.

However, proton particle collisions at twice the power of the first runs, which brought the discovery of the long-sought Higgs boson, will not begin until May, physicists say.

These collisions, at almost the speed of light, create the chaotic conditions inside the LHC close to those that followed the Big Bang 13.8 billion years ago, from which the universe eventually emerged.

The product of the collisions is captured in the collider's giant detectors and is analysed by scientists at Cern and around the world for signs of new information about the cosmos and how it works at the elementary particle level.

Among the aims of scientists at the revamped LHC is to establish the existence of the unseen dark matter that makes up around 96% of the stuff of the universe, but has only been detected through its influence on visible objects.