W and Z bosons are a group of elementary particles. They are bosons, which means that they have a spin of 0 or 1. Both had been found in experiments by the year 1983. Together, they are responsible for a force known as "weak force." Weak force is called weak because it is not as strong as the strong force. There are two W bosons with different charges, the normal W, and its antiparticle, the W . Z bosons are their own antiparticle.