- One of four forces that act between bodies of matter and that are mediated by one or more particles. In order of decreasing strength, the four fundamental forces are the strong force, the electromagnetic force, the weak force, and gravity. The particles associated with these forces, known as force carriers, are the gluon, the photon, the intermediate vector bosons (the Z boson and the W boson), and the graviton, respectively. Some scientists believe that the weak force and the electromagnetic force are both aspects of a single force called the electroweak force. Decay processes in which a subatomic particle is converted into other particles are mediated by the fundamental forces, which relate the decaying particle to the resulting particles; for example, beta decay is mediated by the weak force.
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