What does it mean for a particle to be on Shell?

On-shell describes fields that obey the equations of motion and real particles; off-shell describes fields that don’t have to obey the equations of motion and virtual particles. On-shell are momenta with p2=m2 with the right m2 for the given field; off-shell are momenta that don’t obey the condition.

What does on shell mean in physics?

In physics, particularly in quantum field theory, configurations of a physical system that satisfy classical equations of motion are called “on the mass shell” or simply more often on shell; while those that do not are called “off the mass shell”, or off shell.

What is the field in quantum field theory?

In a quantum field theory, what we perceive as particles are excitations of the quantum field itself. In it, two fields exist: the electromagnetic field and the “electron field”. These two fields continuously interact with each other, energy and momentum are transferred, and excitations are created or destroyed.

What is a charge in quantum field theory?

Abstractly, a charge is any generator of a continuous symmetry of the physical system under study. In the case of local, dynamical symmetries, associated with every charge is a gauge field; when quantized, the gauge field becomes a gauge boson. The charges of the theory “radiate” the gauge field.

What are Mandelstam variables in particle physics?

In theoretical physics, the Mandelstam variables are numerical quantities that encode the energy, momentum, and angles of particles in a scattering process in a Lorentz-invariant fashion. They are used for scattering processes of two particles to two particles.

What is the meaning of shelled out?

shell out. Pay, hand over, as in We had to shell out $1,000 for auto repairs. This expression transfers taking a seed such as a pea or nut out of its pod or shell to taking money out of one’s pocket. [

Are Mandelstam variables invariant?

Why is it important to distinguish on-shell and off-shell fields?

It’s important to distinguish them because on-shell and off-shell are opposite to each other, in a sense. On-shell describes fields that obey the equations of motion and real particles; off-shell describes fields that don’t have to obey the equations of motion and virtual particles.

What are the assumptions of shell theory?

Shell theories are based on the assumption that the strains in the shell are small enough to be discarded in comparison with unity. It is also assumed that the shell is thin enough that quantities, such as the thickness/radius ratio may be discarded in comparison with unity.

What are some examples of on-shell equations?

In classical mechanics for instance, in the action formulation, extremal solutions to the variational principle are on shell and the Euler–Lagrange equations give the on-shell equations. Noether’s theorem regarding differentiable symmetries of physical action and conservation laws is another on-shell theorem.

What is the difference between on mass shell and off mass shell?

In physics, particularly in quantum field theory, configurations of a physical system that satisfy classical equations of motion are called “on the mass shell” or simply more often on shell; while those that do not are called “off the mass shell”, or off shell.