How can there be a massless particle?

In particle physics, a massless particle is an elementary particle whose invariant mass is zero. The two known massless particles are both gauge bosons: the photon (carrier of electromagnetism) and the gluon (carrier of the strong force).

Why do massless particles exist?

Since according to relativity theory a massless particle must move at the speed of light and at that speed there passes no time at all, the particle -its state- is completely frozen in time so it cannot interact, express its existence, so no, there are no massless particles.

Can a massless object Exist?

Since photons (particles of light) have no mass, they must obey E = pc and therefore get all of their energy from their momentum. But an object with zero energy and zero mass is nothing at all. Therefore, if an object with no mass is to physically exist, it can never be at rest.

How is photon massless?

If there was a way (there isn’t; special relativity prohibits it) to observe a photon at rest, you would find it massless. All the relativistic mass of the photon comes from it’s energy. In particle physics when we say mass, we usually refer to the rest mass. This is why we usually say that photons are massless.

How are photons massless?

If there was a way (there isn’t; special relativity prohibits it) to observe a photon at rest, you would find it massless. All the relativistic mass of the photon comes from it’s energy. This is why we usually say that photons are massless.

Are protons massless?

The answer is yes, and the up and down quarks in the proton are already close enough to massless that the proton is hardly affected by making them completely massless.

What does it mean for a particle to be massless?

What it actually means for a particle to be massless is that it can never be brought to rest, it always must move at the speed of light. No one in the universe would ever see such a particle as moving more slowly than the speed of light. Because of that: because a massless particle moves – it has energy of motion and momentum too.

Can a massless particle travel at speed c?

Based on your formula for momentum p, even if a massless particle travels at speed C, p would still be zero (since mass is 0) and energy zero, therefore even massless particles travelling at speed C shouldn’t exist either.

Are photons and gluons massless?

Photons and gluons, two force-carrying particles, are fundamental, so they don’t host the internal tug-of-war of a composite particle. They are also unaffected by the Higgs field. Indeed, they seem to be without mass. Massless particles are purely energy.

Why can’t energy-free particles bounce off of massive particles?

The normal particle then is undisturbed by the collision. So massless particles traveling at speeds less than the speed of light cannot bounce off of massive particles. The other problem is 2) there is no barrier to spontaneous creation of these energy-free particles.