At the Cern press conference today, scientists revealed the results of the experiments conducted at the Large Hadron Collider during 2011. Much excitement had been building up before the meeting, as the expectation grew and rumours circulated that scientists were about to reveal the discovery of the Higgs boson, the particle that gives elementary particles their masses. The “God Particle”—a term that Peter Higgs told me he detests—was to be revealed.
Except it wasn’t. Or at least not quite. Scientists at Cern explained to a full conference room and to the watching world that there had been anomalies in their data that might indicate the presence of a Higgs boson. The statistical bumps the scientists are looking for are represented as standard deviations from the mean, a statistical expression of the unusualness of a given event. Science demands that, in order to confirm the existence of the Higgs, a standard deviation of five—or in the jargon, a 5 sigma event—must be registered. This means that from all the data that is collected at Cern from the trillions of collisions, the event must “stick out” from the norm by far enough for it to be considered a definite sighting of the Higgs boson. However, the two Higgs-detecting experiments at Cern fell short of this degree of certainty: the Atlas experiment recorded events of 2.3 sigma and the CMS experiment, 1.9 sigma, both well short of the required level of certainty.
So the Higgs has not yet been discovered; and yet progress has been made. The search for the boson has revealed some tantalising details. The range of energies at which the particle might be detected is growing ever-more narrow. The technical progress of the machines being used at Cern is also advancing dizzyingly. Particles collide in the machines at such rates that multiple impacts can often happen and these clusters of events must be picked apart before they can be analysed. The detectors at Cern are now able to disentangle up to 20 simultaneous impacts between sub-atomic particles and analyse them all. This constitutes a huge technological leap.
Peter Higgs, the man at the centre of the storm, has decided for now that he will not talk to the press. But an intermediary and close…