According to the current understanding of physics, photons and other point particles do not have mass. They are considered to be massless particles, meaning they do not have any physical substance or weight.
The concept of mass is different from the concept of existence. Mass is a measure of the amount of matter in an object, while existence refers to the presence of something. Photons and other point particles exist in the sense that they have energy and can interact with other particles, even though they do not have mass.
Despite not having mass, photons and other point particles can be affected by gravity. This is because gravity is not caused by mass alone, but by the curvature of space-time. Since photons and other point particles travel through space-time, they can also be affected by its curvature.
Photons and other point particles can move at the speed of light because they have no mass. According to Einstein's theory of relativity, objects with mass cannot reach the speed of light because their mass would become infinite. Since photons and other point particles do not have mass, they can travel at the speed of light.
While current theories do not assign mass to photons and other point particles, there are some theories that suggest they could have a small amount of mass. However, this is still a topic of debate and more research is needed to fully understand the nature of these particles.