In the Standard Model of particle physics, the Higgs mechanism is employed to give mass to certain elementary particles. The Higgs field, which permeates all of space, interacts with these particles, endowing them with mass through a process known as electroweak symmetry breaking. Here's a simplified explanation of how this mechanism works:
Electroweak Symmetry: At very high energies, the electromagnetic force and the weak nuclear force are unified into a single force called the electroweak force. In this unified state, the W and Z bosons, which mediate the weak nuclear force, and the photon, which mediates the electromagnetic force, are massless.
Higgs Field: The Higgs field exists throughout space and has a non-zero value even in empty space. It interacts with certain particles, including the W and Z bosons.
Spontaneous Symmetry Breaking: As the universe cools down and transitions to a lower energy state, the Higgs field spontaneously breaks the electroweak symmetry. This means that the Higgs field settles into a non-zero value, while the W and Z bosons and the photon acquire different properties.
Massive Gauge Bosons: The W and Z bosons, which were originally massless, interact with the Higgs field and acquire mass. This happens because the Higgs field exerts a drag-like effect on these bosons as they move through it. As a result, the W and Z bosons become massive, while the photon remains massless.
Fermion Masses: Fermions, which include quarks and leptons (such as electrons and neutrinos), also acquire mass through their interactions with the Higgs field. The precise details of how fermions obtain their masses involve the coupling of the Higgs field to these particles through a term in the Lagrangian, the mathematical framework that describes particle interactions.
In summary, the Higgs mechanism utilizes the Higgs field to break the electroweak symmetry, allowing particles such as W and Z bosons and fermions to acquire mass. The interaction between these particles and the Higgs field leads to the emergence of mass in the Standard Model of particle physics. The discovery of the Higgs boson at the Large Hadron Collider in 2012 provided experimental confirmation of this mechanism and was a significant milestone in our understanding of particle physics.