It is time to wrap up what turned out to be a much longer series of posts on the Higgs than I anticipated when I started it, probably with a lot more information than readers wanted to know! (For previous posts in this series, click on the Higgs folder just below the blog post title.)

The story of the detection of the Higgs is a prime example of what Thomas Kuhn described as ‘normal science’ in his classic work The Structure of Scientific Revolutions (1962). He said that most of the time, scientists are not seeking novelty but instead are carefully looking for things in which almost everything is known and anticipated, except for a few minor details. In the case of the Higgs, experimenters knew almost everything about it except its mass, and even then we had some idea of the possible range of values. It should not be surprising that the final confirmation comes as somewhat of an anti-climax. [Read more…]

As soon as the discovery of the Higgs was announced in July 2012, there was immediate talk of who would get the seemingly inevitable Nobel prize for it, with some anticipating that it would be awarded even as soon as the same year. This did not happen and I personally did not expect it. For one thing, the Nobel committee is cautious and usually wants to wait until a discovery is totally nailed down before they honor it. Since the LHC has been shut down for a couple of years for upgrades, the corroborating evidence could take some time in coming, although further analysis of the data already taken indicates that the spin of the particle matches that expected of the Higgs. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

So now that the Higgs has supposedly been discovered and an important prediction of the Standard Model confirmed, what’s next? Is it of any use or is it just going to sit on the particle physics shelf as a trophy to the success of big science? This is hard to answer now and may become easier as the properties of the Higgs are studied in more detail. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

Magnetism is weird but in a fun way. Who as a child has not played with magnets and wondered how they worked? And for many a scientist it was what first attracted them to their field. Magnets are our first introduction to the idea of invisible forces that seem to permeate all space and can act to move objects without being in contact with them. Gravity is also such a force but it is too ubiquitous and outside our control for us to notice its peculiarity. We grow up so used to the idea that released objects fall to the ground that we do not give a second thought as to why they behave that way. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

The most obvious design challenge to detect the Higgs particle is that the colliding particles needed to have energies that are sufficient to produce the Higgs. Not knowing the mass of the particle complicated things but having a good idea that the upper limit of mass should be around 1 TeV helped. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

It is time to turn to the issue of how to produce the Higgs particle. Particles that are too short-lived to be found in nature have to be produced in the laboratory. What one does is to use Einstein’s famous relation E=mc². If one has energy large enough, one can in principle produce any particle in the lab. The larger the mass of the desired particle, the larger the energy required. The way the particle is produced is by accelerating easily obtainable stable particles (i.e., those that do not decay quickly into other particles) like protons and electrons (and their anti-particles) and then colliding them with each other so that their energy of motion is converted into mass energy of the new particle. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

In the previous post, we had arrived at the seeming impasse concerning the detection of the Higgs particle in that the particles that we can detect (because they live long enough to reach the detectors) are either those that the Higgs does not directly decay into (photons) or have very small probabilities of doing so (electrons and muons). This is because the strength of the interaction between the Higgs particle and any other particle depends upon the other particle’s mass and the photon is massless while the electron and muon are extremely light. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

In the search for the Higgs particle, we had to overcome two problems: producing it and detecting it. Both those things are difficult and I will first look at the detection part.

The Higgs particle is unstable, in that left to itself it lasts for a very short time. We know this since its mass is much greater than that of other elementary particles and so it should decay into them. As such, in order to detect it, one has to first set up the conditions to produce it and then find ways to detect it either before it decays or, if that is not possible, to find ways to infer that it had existed for a short time. The production and detection of unstable particles like the Higgs stretched the limits of what we can do with current technology (and budgets) and provides a window into the world of particle physics. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

In the previous post in this series, we saw how the Higgs mechanism gave rise to the masses of the weak interaction force particles W⁺, W^–, and Z. We also saw how the process of spontaneous symmetry breaking that was part of that mechanism resulted in the Higgs field having a non-zero average value even in the vacuum, unlike every other field. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]

We have finally reached the stage where we can explain the Higgs mechanism.

In part 3 of this series, I said that the complete set of elementary particles consisted of six quarks, six leptons, six ‘gauge bosons’ (particles that are the agents of the four fundamental forces), and the Higgs particle. In part 7, I said that there were patterns among the 18 non-Higgs particles, apart from some anomalies. (For previous posts in this series, click on the Higgs folder just below the blog post title.) [Read more…]