In particle physics

Particle physics

Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...

, the Goldberger–Wise mechanism
is a popular mechanism that determines the size of the fifth dimension in Randall-Sundrum model

Randall-Sundrum model

In physics, Randall–Sundrum models imagine that the real world is a higher-dimensional Universe described by warped geometry...

s. The mechanism uses a scalar field that propagates throughout the five-dimensional bulk. On each of the branes that end the fifth dimension (frequently referred to as the Planck brane and TeV brane, respectively) there is a potential for this scalar field. The minima for the potentials on the Planck brane and TeV brane are different and causes the vacuum expectation value of the scalar field to change throughout the fifth dimension. This configuration generates a potential for the radion causing it to have a vacuum expectation value and a mass. With reasonable values for the scalar potential, the size of the extra dimension is large enough to solve the hierarchy problem

Hierarchy problem

In theoretical physics, a hierarchy problem occurs when the fundamental parameters of some Lagrangian are vastly different than the parameters measured by experiment. This can happen because measured parameters are related to the fundamental parameters by a prescription known as renormalization...

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