The Higgs Story-Part 10: The non-zero Higgs field in the vacuum

In order to understand the Higgs mechanism, we need to first understand how it came to be that the Higgs field, unlike all the other fields corresponding to the other 18 elementary particles, came to have a non-zero average value in the vacuum. As I said in the previous post in this series, this is the key fact about the Higgs field that leads to it giving mass to the other particles. So how did that come about? [Read more...]

The Higgs Story-Part 8: Gravity and the graviton

Although I will not be talking about the graviton much in this series, it is worthwhile to make a slight detour from the main story line to discuss the role of the gravity force. (For previous posts in this series, click on the Higgs folder just below the blog post title.)

I should point out that unlike with the other force fields, we have not as yet been able to find a way to ‘quantize’ the gravitational field, i.e., find a way to make its particle properties manifest, the way we have been able to do with the theories of the strong, electromagnetic, and weak forces. But despite this, we have been able to make great progress in understanding it. As this article points out, because we have the option of visualizing the behavior of fields using either a particle model or a wave model, we can choose which is the most convenient in any given context, and that has enabled us to overcome the lack of a quantized theory of gravity. [Read more...]

The Higgs Story-Part 7: How fields behave

Perhaps it would be good at this point to take a breath and summarize up the state of play so far. (For previous posts in this series, click on the Higgs folder just below the blog post title.)

In quantum mechanics we have the unifying idea that everything in the universe is made up of relativistic quantum fields that correspond to elementary particles and which I will refer to in the future as simply fields. These fields are wavy-like vibrations and differ from classical waves in that they are not vibrations of a medium (like water for ocean waves or air for sound waves) but vibrations of space itself, if you can imagine it. The word quantum in its name comes from the fact that the energy of vibrations of these fields can only change by small discrete amounts (or ‘quanta’) and not continuously, the way that classical vibrating fields can. [Read more...]

The Higgs Story-Part 6: Relativistic quantum fields

In the previous post in this series, I introduced the idea of fields and also said that while the Schrodinger equation and wave function overcame some of the problems with understanding how particles could also have wave properties, there were still difficulties in both interpretation and practice. The person who made the next major advance and created the framework for our present understanding of all matter was Paul Dirac (1902-1984) whose views on religion I wrote about over the weekend. [Read more...]

The Higgs Story-Part 5: Fields as a unifying concept

In the previous post in this series, I said that wave mechanics as represented by the Schrodinger equation was a major advance in our understanding of physics. It adopted the view that all entities had both particle-like and wave-like properties and each of them were manifested by constructing the appropriate experimental set-up. If you set up an experiment that looked for the wave characteristics of (say) an electron, you detected its wave properties. If you set up an experiment that looked for the particle characteristics, you saw that too. [Read more...]

The Higgs Story-Part 4: Particles and waves

To better understand the Higgs field and how it works its magic, we need to make a detour into the history of physics and look at the similarities and differences between particles and waves. In ordinary life (what we call the ‘classical’ world) a particle is a localized object that is usually of small size, has a fairly well defined boundary, and a mass. A grain of rice and a speck of dust are particles. A wave, on the other hand, is the name we give to the pattern of vibrations traveling through some medium (think of the waves in water or sound waves traveling through air) that is extended, has no sharp edges, and does not have mass. [Read more...]

The Higgs Story-Part 3: The basic elements of the Standard Model

All the stuff of everyday matter is composed of atoms that are made up of protons and neutrons and electrons. The three quarks in the protons and neutrons consist of just the up and down varieties and make up only about 1% of their masses, if we use the current quark mass values (see part 2 in this series). There are also gluons that hold the quarks within the proton and neutron so that they never become isolated free particles the way that (say) electrons do . [Read more...]

The Higgs Story-Part 2: What ordinary matter is made of

Everyday matter is made up of protons, neutrons, electrons, and something called electron neutrinos. These particles interact with each other via one or more of four forces: gravity, electromagnetic (which is the unified force of electricity and magnetism), strong nuclear, and weak nuclear. Almost all of everyday life could be explained pretty well with just this short list of four particles and four forces. [Read more...]

The Higgs Story-Part 1: The three faces of Higgs

Around the time of reports last year about the discovery of the Higgs particle at the LHC (Large Hadron Collider), reader Anthony in a private email to me asked a good question. The Higgs particle is repeatedly referred to as the means by which all other particles get their mass. If not for the Higgs, elementary particles like the electron, muon, and the like would be massless and like all massless particles would be zipping around at the speed of light. At present, there is no explanation for why these particles have mass at all let alone the actual values that they do have. According to current theory, it is the Higgs phenomenon that gives all the other particles their mass. So how does that happen? [Read more...]