Which force is carried by particles with no rest mass?

In the Standard Model, the electromagnetic force is mediated by photons, and photons have zero rest mass. A massless force carrier can travel indefinitely, which is why electromagnetic effects can be felt over huge distances. That is very different from the weak force, whose carriers, the W and Z bosons, are massive and therefore short-ranged. Photons also make up light, so the force and radiation are tightly linked. This simple feature helps explain why electromagnetism is so pervasive in everyday life.