Dr. Christopher Bird

As most of you are aware by now, two weeks ago the Large Hadron Collider detected signs of the elusive Higgs boson and confirmed its existence. Yesterday I answered some of the technical questions around the Higgs mechanism, and so today I will try to answer some of the more general questions that readers have been asking.

What use is it to the average person?

This question has been asked of every scientific discovery since the dawn of time. Unfortunately the answer often involves technology so far into the future that it is not clear. For example, in 1901 physicists were concerned that their models predicted certain types of hot objects would be producing devastating levels of radiation, when in practice they didn't. Max Planck resolved this by requiring that radiation act as particles or as discreet packets of energy. It was a discovery only of interest to scientists, and clearly had no practical use. Thirty years later it had become the theory of quantum mechanics, and by the 1950 it was used to generate such things as lasers and transistors. In modern times, all computers, digital cameras, radios,TVs, and really all electronics depends on quantum mechanics. Our entire world is dependent on this simple little abstract idea from more than a century ago. 
The history of science and mathematics are filled with such examples. It was over a century after Riemann developed alternatives to traditional Euclidean geometry that they became required (through the theory of general relativity) for use in GPS and future space travel. Both the electric generator and the telephone were considered useless toys when first developed. Maxwell's theories on electromagnetic waves were considered just as abstract when presented, but a century later were turned into TV and radio signals. And it was NASA research into the upper atmosphere of Venus that led to the discovery of the Greenhouse effect.  So where will the Higgs lead us? No one knows.
Also there are side benefits to high level research. The same research facility that produced the Higgs, CERN, produced the world wide web which we associate closely with the modern internet. The advances in superconducting magnets will help advance the development of MRI machines in hospitals. A few months ago it was determined that the smaller particle accelerators that helped test equipment for the LHC could be used now to generate medical isotopes for cancer treatment. The LHC also needs to process huge amounts of data very quickly, and the algorithms and hardware developed for that purpose will undoubtedly find other uses in this modern computer dependent society.   So although finding the Higgs may seem esoteric, the side benefits now and the direct benefits in the coming decades make it a worthwhile venture.

What does it have to do with God?
 
Nothing. Unfortunately in the 1990s there came a popular physics book which nicknamed the Higgs as the 'God particle'. The name has stuck with reporters and science authors, but it has nothing to do with religion or deities at all.
 
Now that the Standard Model is complete, is physics over?

Not by a long way. The Standard Model was developed through the 1950s and 1960s to explain all of the known physics at the time. It describes all matter and (almost) all the forces that we experience in everyday life. Completing it with the Higgs was a huge accomplishment.
But much more has been discovered since it was first developed. Of the four fundamental forces of nature, only three have complete theories. The quantum theory of gravity is still a mystery, and has become the focus of a lot of research in recent years. In the past decade we also discovered that the bulk of the Universe - in fact 95% of the energy of the Universe - is in the form of dark matter and dark energy which are completely outside of the Standard Model. Add in technical points - such as why each parameter of the Standard Model takes the value it does, or why it has the number of particles that it does - and you quickly realize that the search of new physics is still flourishing.

I keep hearing about supersymmetry and its connection to the Higgs - what is it? 
 
There is one problem with the Higgs model that tends to be forgotten - the lightness of the particle. The mass of the Higgs depends on many other variables, among which is the inverse of the strength of gravity. Because gravity is so weak, this contribution is huge. So how do you have a mass, which is the sum of dozens of terms, some of which are 100,000,000,000,000 times larger than the observed Higgs mass, and get such a tiny value at the end?
There are actually a few ways to resolve this, but one of the simplest is through supersymmetry. If every particle has a twin, with almost identical properties but with a slightly different spin, then the terms will cancel out and everything works fine. Except that we have never found even one of these supersymmetric partners, when the theory predicts we should know of dozens of them. Maybe the LHC will find them, maybe it won't. There are alternatives, so it won't be as devastating as if the Higgs hadn't been found, but it will still be a huge discovery if they do find it.
 
Is this the end of the LHC? Has it completed its job and will shut down now?

Far from it. The LHC has enough energy and accuracy to now search for other signs of new physics. There is a good chance that it will discover dark matter particles, maybe supersymmetric particles, possibly signs of higher dimensions, maybe even small black holes (although I personally believe this won't happen due to constraints from astrophysics, but we can never be certain). 

All we know for certain is that the Large Hadron Collider will run for many more years, and likely provide many more great discoveries for the scientific community.