Hypothetical force-carrying particle (gauge boson) for gravitation. Although there is, as yet, no generally accepted quantum theory of Attractive force between all matter - one of the four fundamental forces. Click on Term to Read More, it is widely believed that it should be possible to formulate gravitation in quantum terms with the gravitational interaction between particles of matter conveyed by gravitons. The hypothesized graviton has zero mass, zero charge and a spin value of 2 (in units of h/2π).
Some or all content above used with permission from J. H. Wittke.