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the process

the process

Higgs Boson Discovery announcement by Peter Higgs

2y ago
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Description

4th of July 2012, this is the day the Higgs Boson was discovered by the human race. It must be fate that just as the American's gained independence from the British Empire on this day, so to does the origin of mass in our universe gain its independence in a unique field that permeates our universe. After 40 years of searching, Peter Higgs can now announce to the world how he has seen the culmination of his life's work finally blossom into a tangible result, a result which has brought an all too human emotion to this triumph. The Higgs field and resulting Higgs boson are a vital part of the Electroweak Interaction and the Standard Model of particle physics as a whole. In the absence of the Higgs field, when a Local Gauge is applied to the Lagrangian of the Electroweak Interaction we are left with force-carrying bosons that are mass-less, the W and Z Bosons. This would be okay for the Photon as it has no mass however the W and Z bosons are massive particles, with masses of ~80GeV and ~90GeV respectively. The Higgs mechanism was the most favoured explanation for solving this problem. In brief, the Higgs field is introduced to 'break' the symmetry of the Electroweak theory, which allows its bosons to have mass while at the same time conserving the principles of the standard model. This Higgs mechanism is important as it not only explains how the heavy bosons become massive but also provides an explanation as to how the fermions come to have mass. The Mechanism of the interaction is simple to understand. Where the Electroweak Interaction couples to electric and weak (or flavour) charges and the Strong Interaction couples to colour charge, the Higgs interaction couples to mass. The process by which the Higgs gives fermions mass is via the Yukawa potential. This potential gives the coupling strength of the Higgs to all types of fermions, the stronger the coupling, the more mass the particle will have. Hence the Higgs Boson couples more strongly to more massive particles, hence the energies of the LHC were necessary to create the most massive particles for the Higgs to couple with. Why we needed this boson is a bit more complicated, but here is a reasonably short explaination which corresponds to Peter Higgs (and my own) research into the matter. any feedback is always appreciated by fellow scientists. In the Electroweak interaction you can examine the Lagrangian in a similar way to those for Quantum Electrodynamics (QED) and also Quantum Chromodynamics (QCD). Starting with the Dirac Lagrangian, when a Local Gauge is applied the resulting Lagrangrian is not invariant under the transformation. The local gauge transformation applied to the Langrangian is dependent on the symmetry, for example for the weak force we use SU(2) symmetry as we want physics invariant under swapping up-like and down-like fermions. When a Local Gauge Symmetry is applied to the Electroweak Lagrangian it does not remain invariant under the gauge transformation. This can be rectified by the introduction of appropriate fields, which have associated mass-less bosons W1, W2, W3 and B. The SU(2)xU(1) symmetry of the electroweak theory is non-abelian which means that the bosons interact with each other as well as with fermions. The Electroweak theory needs to end up with three massive bosons (2 charged and 1 neutral) and also a mass-less boson. The Goldstone Theorem provides a mechanism by which the 4 mass-less bosons from the original symmetry can become the four Electroweak bosons described above. The Goldstone theorem states "that for any continuous symmetry broken, there exists a mass-less particle, the Goldstone boson." The result is that for each broken generator, there is a resulting mass-less scalar boson. The Higgs mechanism is the process applied to Electroweak theory. A complex doublet Higgs field can be included in the theory and this Higgs field breaks the symmetry of the problem while retaining local gauge invariance. This Higgs field (t...