h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

It's time to update this article. Douglas Adams would have really liked to know all about the discovery of the Higgs boson at CERN. Does anyone here know what were his thoughts on the subject?

The Waldegrave Challenge winners was a great inclusion in the original article, but the "Politics and the Higgs", copied many times in expository pieces about the Higgs, definitely needed some updating from someone who actually knew what they are talking about.

So here is my suggestion for a revision /addition. I don't think I missed changing a single word from the Waldegrave, and the thought experiment is an original one (something that you definitely cannot get away with on Wikipedia, for instance. Enjoy.

Higgs without the Politics
By Daniel Shawen

1. The Higgs Mechanism in 2D

Imagine a rather large billiard table with a number of what appear to be ordinary billiard balls evenly spaced and partially submerged in 1/2" of liquid helium (composed of bosons) uniformly distributed across its perfectly flat level surface. For the purposes of the analogy, assume that the liquid helium will not be able to climb up the edges of the billiard table or siphon itself off in a similar manner. The liquid helium is there to remove the usually spooky "action at a distance" from this thought experiment in a manner that does not require filling a room with politicians, or members of the press. This is a much clearer explanation than those that rely on the propagation of rumors. It also helps with the visualization of boson energy / mass exchange, since liquid helium is essentially a superfluid composed entirely of bosons.

Each of the balls inexplicably contains a pump mechanism that continuously sucks liquid helium out of the surface of the shallow pool through porous holes in the bottom. For the purposes of the analogy, assume that the cue ball, which represents a particle of ordinary matter moving through space has more suction than the other evenly spaced balls on the surface of the table, which represent Higgs bosons. The suctioned liquid helium evaporates or dispelled in such a manner that the fluid taken in or expelled does not affect the 2D momentum of any of the balls or groups of balls that are set in motion. The liquid helium level on the table does not change because an external pump continuously replenishes the liquid helium level. Balls are more strongly attracted to something like a cue ball because it has more suction, and will cluster round it as it moves through clusters of other balls on the table. It attracts the balls closest to it, while the balls in its wake return to their more or less even spacing after the cue has passed. The cluster of balls surrounding the cue as it moves acquire a greater mass, and have more momentum for the same speed of movement across the table. Once moving , the cue and its cluster of balls is harder to stop than the cue ball alone. Once stopped, it is harder to get the cue and its cluster moving again because of the additional mass of the cluster. This is very similar to the way inertial mass works.

In three dimensions, and with inertial dynamics consistent with the theory of Special Relativity, this is the Higgs mechanism. In order to give particles mass, a background field (liquid helium and evenly spaced billiard balls) is invented which becomes locally distorted whenever any particle having mass (or energy) moves through it. The clustering of the field around particles moving or at rest - generates the particle's mass. The idea of the Higgs mechanism comes more or less from the physics of solids. A solid that is a conductor of electricity contains a lattice of positively charged atoms in a crystalline lattice. When an electric current flows, the atoms are attracted to moving electrons, causing the electron's effective mass to be as much as 80 times the mass of a free electron.

The Higgs field is a sort of hypothetical lattice of virtual Higgs bosons in the vacuum which pervades all of spacetime. We need it for the Standard Model because otherwise, it is impossible to explain why the Z and W bosons (carriers of the electroweak nuclear force), are hundreds of times more massive than a hydrogen atom, while the photon (which carries electromagnetic forces) is for all intents and purposes, massless.

2. The Higgs Boson

Now consider the effect of a moving drain passing through our pool table of evenly spaced balls. The drain is small, and with a perforated cover so that that billiard balls cannot prevent liquid helium from draining out . Those balls nearest the moving drain hole will likewise cluster around it. A wave of clustering passes through the room. It may spread to all the corners or it may form a compact bunch which carries the news along a straight line to other side of the table. Since the momentum is carried by clusters of balls and since it was clustering that gave the extra mass to the wave of clustering, then the drain following clusters also have mass.

The Higgs boson is predicted to be a clustering of bosons in the Higgs field. The Higgs has been discovered, so there is now no question of this. Waves of clustering without or without a massive particle such as the W or Z bosons produce waves that can behave as if they are particles. They are called photons and they too are bosons.

OK, obviously, I missed one seminal idea that would have helped the simulation.

If the billiard table were filled just a bit higher with liquid nitrogen, it would have provided for there to be waves (particles with no mass) riding on the surface of the liquid helium, enough to weakly interact with the dynamics of the billiard balls (give them mass, perhaps?), while also clearly demonstrating how waves such as light (photons) can propagate in the medium without getting bogged down with having too much mass.

Others like Sean Carroll ('Particle at the end of the universe' fame) have suggested that the Higgs field be visualized as a sort of thick energetic fog, because it limits the range of the weak force to just what it needs to be in order for there to be hadrons, nuclei and atomic structure in general.

Obviously, a lot more work needs to be done both at CERN and elsewhere to determine if the Higgs just discovered is the only boson of its kind, or whether it has some other symmetric partner in the virtual particle world that allows it to do whatever needs to be done to keep the universe as we know it intact.

Yes, this entry definitely belongs in H2G2. If a Higgs cascade should occur, don't panic; just ride the wave. Thanks for your indulgence.