In particle physics, majorons are a hypothetical type of Goldstone boson that are conjectured to mediate the neutrino mass violation of lepton number or B − L in certain high energy collisions such as e− + e− → W− + W− + JWhere two electrons collide to form two W bosons and the majoron J. The UB–L symmetry is assumed to be global so that the majoron is not "eaten up" by the gauge boson and spontaneously broken. Wikipedia