Physics is often viewed as a dispassionate and purely objective activity. So how, wonders Robert P Crease, do we explain the reaction of Peter Higgs when the boson that bears his name was discovered?
Nobody who has seen the images will forget Peter Higgs’ watery eyes. Captured at CERN’s main auditorium on 4 July 2012, the video shows the British theoretical physicist holding a tissue as lab bosses announce that the Higgs boson has been discovered. Higgs, who was then 83, has welled up and removes his glasses to daub his face. But do those tears reveal the emotion of a particularly sensitive man? Or do they indicate emotional currents intrinsic to life as a physicist?
According to a view long enshrined in textbooks and ratified by traditional philosophers of science, physicists are investigators trained to apply physical and conceptual tools to unravel the puzzles of nature. Whatever moods strike them as that work unfolds reflect only the subjective responses of individuals; the moods on show are irrelevant to the practice of physics. Higgs must be simply a man prone to tears, so this view goes.
Do Peter Higgs’ tears reveal the emotion of a particularly sensitive man? Or do they indicate emotional currents intrinsic to life as a physicist?
But according to a more all-inclusive approach to science, which treats it as consisting not just of products but of practitioners too, those tears are different. Physicists belong to of a way of life that values solving nature’s puzzles – and moods are as intrinsic to that way of life as they are to ordinary life. Living in a world in which nature appears manipulable and measurable – and full of puzzles to be solved – physicists experience everything from awe, boredom, confusion and disappointment to discouragement, obsession, pressure, shock, scepticism and more.
Discovering the Higgs boson: a day in physics like no other
Sure, those feelings aren’t necessarily different from what we experience in everyday life, but they are intrinsic to physics life, and therefore to physics itself. In fact, the puzzle-solving world that physicists inhabit is rather like sport, where athletes bring their all to the ebb and flow of a game. If you spot an emotionless athlete in an exciting match, you assume they’re either good at hiding their moods or are simply disengaged. Similarly, if you encounter a physicist who is blasé about their work or about their setbacks and successes, you can’t help but wonder how talented they really are.
Even the notoriously impassive theorist Paul Dirac was privately moody, as revealed by his recollection of the time he realized the likely relevance of “Poisson brackets” to quantum mechanics. Not knowing enough about this mathematical operation and being unable to find it discussed adequately in his textbooks, Dirac was in despair to find that the library was closed on that particular Sunday. He was forced to wait “impatiently through the night and then the next morning” until the library reopened.
Now and again there is some dramatic and sensational event that provokes a particularly intense and powerful emotion.
The conventional view of science, however, omits these moods, labelling them subjective and dismissing them as something in the domain of psychologists. But there is a “physics world” that practitioners are caught up in. Usually, it’s everyday stuff like conversing with colleagues and learning what others are up to; of hearing about new ideas, reading journals and ordering supplies; of planning and carrying out new projects. Now and again, though, there is some dramatic and sensational event that provokes a particularly intense and powerful emotion.
The mass thing
The announcement of the discovery of the Higgs boson was one such event. What a decisive piece of what an extraordinary puzzle! Hundreds of theoretical pieces had to come together to create the architecture of the Standard Model of particle physics, and decades of development in accelerator and detector technology were required. The Standard Model also had to incorporate all those strange particles discovered first in cosmic rays and then even more produced in accelerators.
That model required theorists to develop countless schemes to organize these particles into families, with experimentalists having to identify all the family members and their properties. All those forces in and between particles had to be consolidated into one. Gauge symmetry and broken symmetry had to be invented. Every now and then some deep flaw would appear in the evolving architecture – parity violation, charge–parity violation – that had to be resolved.
But a piece missing from the beginning was how mass figures in this architecture. The invention of the necessary idea itself took years and required many seemingly unrelated steps from seemingly unrelated fields.
Birthday boson: 10 years of living with the Higgs particle
Julian Schwinger discovered that attempts to link the weak and electromagnetic fields were stymied by the fact that electrically charged bosons are not massless. Yoichiro Nambu found the idea of hidden symmetry was key to superconductivity. Jeffrey Goldstone saw that the breaking the symmetry creates massless bosons. Philip Anderson used ideas from plasma physics to show that it’s possible to have massive gauge bosons, while several other theorists showed that bosons can become that way by absorbing the Goldstone boson.
Peter Higgs’ work not only described such a boson but also proposed ways that it might be identified experimentally. All these things, and many other contributions, had to go into fitting that piece into the blueprint of the Standard Model, showing that its blueprint was sound. And then came the enormous technical and experimental challenge of hunting for the boson – a job that was completed in 2012 – almost half a century after the boson’s first description.
The critical point
Peter Higgs was not alone in experiencing feelings that day at CERN during the announcement of that particle. There wasn’t a single mood in the room, of course. Some were celebrating the discovery after contributing to it, or were proud of the discovery despite working in another area in or outside CERN. Others may have been dismayed at having sought – but failed – to contribute, or at having had their contributions unacknowledged. These moods were all present and inseparable from the way of life of a physicist.
It is just that Higgs’ was more visible – and an alert camera operator caught it on film.
