The world was set alight by the discovery of what looks like the Higgs boson earlier this month. For Peter Higgs, who proposed the particle's existence 48 years ago, it was a week to remember. He came up with the mechanism for how matter gets its mass at around the same time as other groups and predicted the particle that bears his name. He is professor emeritus at the University of Edinburgh, United Kingdom, where a new center for theoretical physics will be opened in his honor.
Jessica Griggs: This chapter in the Higgs boson story must have been a bit of a roller-coaster ride. Did the announcement by the European Center for Nuclear Research, or CERN, on July 4 take you by surprise?
Peter Higgs: The week before, I was at a physics summer school in Sicily. I didn't take any Swiss francs with me, and my travel insurance policy expired the day I was supposed to fly back to Edinburgh. As the week went on, rumors began to fly, but it wasn't until the Saturday before the announcement that we knew for certain that something was up. We got a phone call from John Ellis, the former head of theoretical physics at CERN, saying, "Tell Peter that if he doesn't come to CERN on Wednesday, he will very probably regret it." I said, very well then, I'll go.
JG: How were you feeling at that point?
PH: I was getting excited. The final confirmation that good news was coming came the evening before the CERN seminar. We had dinner at John Ellis's house, and he cracked open a bottle of champagne.
JG: The teams on ATLAS and CMS, the experiments at CERN looking for the Higgs boson, were 99.99994 percent sure that what they were seeing wasn't a fluke—a 5-sigma result, the gold standard for such work. Were you surprised that the evidence was so strong?
PH: That was amazing, especially as in the weeks before I had been visiting various high-energy physics groups working on ATLAS or CMS, and everywhere the researchers were sure that CERN would not get to 5-sigma by the start of the conference on high-energy physics in Melbourne, due to begin on the day of the announcement.
JG: It was obviously an emotional moment when the announcement was made.
PH: I was asked why I burst into tears after the presentation. During the talks I was still distancing myself from it all, but when the seminar ended, it was like being at a football match when the home team wins. There was a standing ovation for the people who gave the presentation, cheers and stamping. It was like being knocked over by a wave.
JG: How did you celebrate?
PH: With a can of London Pride on the flight back to London.
JG: You came up with a mechanism to account for the existence of mass, predicting the Higgs boson in the process. But there was opposition to your ideas at first. Do you feel vindicated?
PH: Yes, well, it's nice to be right sometimes. I didn't expect it to happen in my lifetime at the beginning. This changed when the big colliders were built: LEP (the predecessor of the Large Hadron Collider, or LHC, at CERN), the Tevatron, and now the LHC. At the beginning, no one knew what the mass of the Higgs would be, so it could have been too high for it to be discovered by these colliders.
JG: There were those who doubted the existence of the particle. Did you ever think that way?
PH: No, I didn't really. The Higgs is so crucial for the consistency of the mechanism. You can remove the particle as a theoretical exercise, but then the mechanism becomes nonsense. I had faith in the theory behind the mechanism, as other features of it were being verified in great detail at successive colliders. It would have been very surprising if the remaining piece of the jigsaw wasn't there.