Majoron

Not to be confused with Majorana fermion.

Majoron

Composition	Elementary particle
Statistics	Bosonic
Status	Hypothetical
Symbol	J
Theorized	Y. Chikashige, R. N. Mohapatra, and R. D. Peccei
Mass	unknown
Electric charge	0
Spin	0

In particle physics, majorons (named after Ettore Majorana) are a hypothetical type of Goldstone boson that are theorized to mediate the neutrino mass violation of lepton number or B − L in certain high energy collisions such as

e− + e− → W− + W− + J

Where two electrons collide to form two W bosons and the majoron J. The U(1)_B–L symmetry is assumed to be global so that the majoron isn't "eaten up" by the gauge boson and spontaneously broken. Majorons were originally formulated in four dimensions by Y. Chikashige, R. N. Mohapatra and R. D. Peccei to understand neutrino masses by the seesaw mechanism and are being searched for in the neutrino-less double beta decay process. There are theoretical extensions of this idea into supersymmetric theories and theories involving extra compactified dimensions. By propagating through the extra spatial dimensions the detectable number of majoron creation events vary accordingly. Mathematically, majorons may be modeled by allowing them to propagate through a material while all other Standard Model forces are fixed to an orbifold point.

Searches

Experiments studying double beta decay have set limits on decay modes that emit majorons.

NEMO has observed a variety of elements . EXO and Kamland-Zen have set half-life limits for majoron decays in xenon.