"Quark Disasters." Delivered at the British Association for the Advancement of Science Annual Festival, Glasgow, Scotland, September 2001
Benjamin Allenach, European Center for
Nuclear Research (CERN)
Think quarks, leptons, and bosons are too small to harm you? Think again. Someday, they and their sister particles could unmake your whole cosmos.
Just in case you didn't have enough to worry about, think about this: A random fluctuation of the vacuum of space anywhere in the universe could flip the cosmic light switch to "off," plunging the whole of creation into darkness. Light and the electric force holding atoms together would disappear. All matter would disintegrate into lumpy disorder, and what was left of Earth would collapse under its own gravity.
According to physicist Benjamin Allenach of the European Center for Nuclear Research (CERN), this scenario comes from the theory of particle physics called supersymmetry. The theory proposes a set of sister particles -- "super-partners" -- for each of the known particles in the Standard Model of particle physics.
"Supersymmetry is really a beautiful mathematical symmetry between particles and forces," says Allenach. Beautiful, that is, unless it turns ugly. At some point in the history of the universe, supersymmetry got broken. As a result, the super-partner particles are all heavier than their known particle counterparts. And that could shake up the universe a bit.
In the Standard Model, the universe's vacuum isn't empty or quiet. It's fizzing with spontaneously appearing and disappearing particles, permeated by an energy field named for physicist Peter Higgs. The Higgs field particles fill the vacuum like a jelly, dragging at the particles that pass through it. If the jelly slows a particle down, it gets mass, and that's where the trouble begins.
A spontaneous "quantum flip" -- that is, the random spontaneous appearance of a pair of super-partner particles in the vacuum -- could introduce heavier Higgs super-partner particles, thickening the jelly. Photons passing through the thicker field would feel the drag, and these normally massless energy particles would gain mass. There would no longer be enough energy to produce photons, and light and other electromagnetic energy would disappear. The new, lower-energy state would spread to every corner of the universe.
So now what? Should you lie awake at night, trembling with apocalyptic worry? Allenach does not think so. The odds, he says, are less than one in 169 billion. You're more likely to win the lottery two weeks in a row. So go ahead and turn out the light.
"If one constrains simple models of low-energy supersymmetry with current data, one finds that most available parameter space lies in a meta-stable vacuum of the scalar potential. The global minimum is charge and color breaking, but the tunneling rate tends to be negligible; the lifetime of the meta-stable state being greater than the age of the observable universe."