Saturday, June 23, 2012

Where does Mass Come From? Announcement July 4th, 2012!

On July 4th in Melbourne, Australia, the 5000 physicists of the ATLAS and CMS collaborations from the Large Hadron Collider in Geneva, Switzerland are going to announce their results on the search for a particle that has to do with the origin of mass—the Higgs boson.

In December of 2011, these two giant groups of scientists, engineers, computer programers and support staff, announced their first concrete results on the search for the Higgs boson.  Now, they have about twice the data, and they will be able to make a much more definitive claim.  Scientists and nonscientists around the globe are waiting excitedly for the unveiling of the results.

So what is the Higgs boson?

Imagine a world where everything is like light, able to zip around at 300,000 km/s (186,000 mi/hr).  Light is made up of just one kind a particle, called a photon.  If all the particles were like that, they would be massless.  They would not form into atoms and molecules.  Except for the frequency (color) of the various kinds of light, everything would be much the same.

It turns out our understanding of particle physics is very much like that, except that there is a mechanism which gives the particle mass so most things can't travel at the speed of light, and so they aren't all the same, and they can form atoms and molecules.  That "except" part is all due to a mechanism called "spontaneous symmetry breaking" (never mind the big term for now).  So we have a beautiful theory of lightlike massless particles which is "fixed" to explain the world as we see it by this mechanism.  The theory has been tested backwards and forwards—all of it except for this crucial mechanism.

And that's where the Higgs boson comes in.  The mechanism predicts that this particle must be there.  The trouble is, it requires an enormous amount of energy (on the scale of elementary particles) to make one, and so our biggest colliders have not been big enough to produce it.  Until now.

The Large Hadron Collider is big enough and collides enough particles per second to see it.  If the Higgs is there, as predicted in the simplest model, the LHC should see it and report evidence or even observation of it on July 4th.  If they don't see it (contrary to the rumors), then the simplest model is wrong.

So this July 4th, keep an ear and eye peeled for news about the origin of mass and the Higgs boson.

P.S.: Please never refer to the Higgs boson as the "God particle", a term made up by a PR guy, because it simultaneously insults religion and science. (It's particularly ironic because the Higgs boson doesn't do anything, not even give mass to particles—it is the smoking gun for the mechanism which does.)