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.