There are several subatomic particles that have zero rest mass. Here are some examples:
Photon: The photon is the elementary particle of light and other forms of electromagnetic radiation. It has zero rest mass and travels at the speed of light. Photons are the carriers of the electromagnetic force and do not experience gravitational interactions.
Gluon: Gluons are the force-carrying particles of the strong nuclear force, which binds quarks together to form protons, neutrons, and other particles. Gluons also have zero rest mass and mediate the interactions between quarks.
W and Z bosons (in certain contexts): The W and Z bosons are the force-carrying particles of the weak nuclear force, which is responsible for processes like radioactive decay. While the W and Z bosons are generally considered to have non-zero rest mass, in the context of the electroweak interaction, where the electromagnetic and weak forces are unified, the W and Z bosons can be treated as massless particles.
It's important to note that while these particles have zero rest mass, they can still possess energy and momentum due to their motion. Additionally, the concept of rest mass is distinct from relativistic mass, which takes into account the energy and momentum of a particle.