Friday, March 11, 2011

Who Ordered That? - Part 6

The Higgs Boson

The Higgs boson was theorized by a group in the mid 1960’s led by Peter Higgs. In this theory there is a Higgs field which permeates all space. Particles which interact with this field appear to us as having mass, particles which don’t, appear massless. This field explains why forces act the way they do.

The Higgs boson is an important element of the standard model theory. It is the only remaining particle predicted by the standard model that has not been observed. This was one of the main driving forces in the construction of the Large Hadron Collider in CERN and the Tevatron at Fermilab. In these accelerators it is hoped that we will get our first glimpse of this elusive particle.  The discovery of this particle would go a long way to helping physicists explain why particles have the mass they do and why forces work the way they do.
They is of course the question does the Higgs particle even exist? A positive or negative result would yield a change in understanding. If Higgs isn’t found it means we must find a new theory and if it is found we can build upon it to try and integrate gravity in to an all inclusive theory. So what lies beyond the standard model and the Higgs boson?

Beyond the Standard Model

The standard for all its power has limits to its knowledge which it cannot answer.
  • Can we unify all the fundamental forces?
  • Why only three generations of leptons and quarks?
  • Is there something more fundamental than the quark and lepton families?
  • What are Dark Matter and Dark Energy?
  • Why is there more matter than anti-matter?
  • What is the explanation of neutrino mass?
  • Why are the fundamental forces so vastly different in terms of strength?
  • Where does the cosmological constant originate from?

These are just some of the questions the standard model is not able to answer. To try to answer these questions there are several theories.

String theory is one of the major developments of the last 40 years. It attempts to find some common ground between quantum physics and general relativity. In this theory, it proposes that quark and leptons are one dimensional strings. The vibrations of these strings give rise to their apparent properties. This theory, it is hoped, will reconcile gravity with quantum theories and could possibly lead to a theory of everything. String theory isn’t without its flaws; it is by its nature untestable. It has also failed to make any concrete predictions. It is viewed by many as a mathematical framework rather than an actual physical theory.

Another candidate is the supersymmetric standard model. In this model each particle has a partner which is at a much higher energy level. This symmetry would help explain several key questions which the standard model fails to do. In this model it predicts that the fundamental forces are somehow bound at higher energies. This theory indicates that at some time proceeding the big bang there was a singular force called the super force. From this super force we got the four fundamental forces. As the universe cooled after the initial explosion these fundamental forces arose, gravity first followed by the strong, weak and finally EM force. Another prediction from this theory is a candidate for dark matter. We may get an answer for this theory very soon. In this theory the first of these super partners should be a particle called the neutralino. If predictions are correct it may be possible that it could be observed at CERN.

So here we are, with the LHC and Tevatron operational we are possibly on the verge of a major paradigm shift in physics. Just as at the beginning of the 20th century, when the first hints of atomic theory and quantum theory excited and fired the imaginations of physicists, here we await the first glimpses of new ground in the search for a theory of everything. 


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