Why is the Higgs boson so important to physicists? This is the question answered by Nathalie Besson, from the CEA, who studies the W and Z bosons with the Atlas detector at the LHC. This particle was only a prediction and its discovery validated the standard model, the basic theory of particle physics, which works very well but does not predict everything, for example dark matter and dark energy. Consolidated by the discovery of the Higgs boson, it can be better tested to, perhaps, lead physics towards new paths.
the Higgs bosonthrough the ” Brout-Englert-Higgs mechanism (BEH) and its scalar field, is the keystone of the standard model. This combines the equations of the electroweak model describing the electromagnetic forces and the radioactivity beta with those of the quantum chromodynamics (QCD) describing protons and neutronsbut leaves out the general relativity ofEinstein. In the beginning, the equations that were to become the basis of these modern theories of particle physics, the equations of Yang Mills that we find in particular at the heart of the electroweak model, led to a big problem. They seemed to forbid the mediating particles of the weak nuclear force (bosons related to the photon) to have massesthis must therefore have an infinite range, which is in strong contraction with all the observations.
The use of the BEH mechanism made it possible to give a mass to the W and Z bosons of this model, solving at the same time renormalization problems related to the appearance of infinite quantities in the calculations while observation gives finite measurements.
Measuring the Higgs boson is testing the standard model
Long before its discovery at Cern in 2012, the Higgs boson was already well known by calculations within the framework of the standard model, leading to verified predictions since the 1970s and, above all, 1980s. Its mass remained however enigmatic and some theories allowed to do without it more or less to build the standard model… or indicated that it did not exist.
In contrast, many of the theories that go beyond the Standard Model, including those that would explain the nature of dark energy and black matter, imply that the behavior and nature of the Higgs boson differs from what the Standard Model says. It was therefore important to verify its existence, so as to consolidate and clarify the predictions of the standard model, so as to be able to identify phenomena that escape it, or even open the gate on a new physics.
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