A bilepton is a hypothetical particle predicted by the minimal 331 model

331 model

The 331 model in particle physics offers an explanation of why there must exist three families of quarks and leptons. One curious feature of the Standard Model is that the anomaly cancels exactly, for each quark-lepton family, of which we know three...

. It is a spin one gauge boson

Gauge boson

In particle physics, gauge bosons are bosonic particles that act as carriers of the fundamental forces of nature. More specifically, elementary particles whose interactions are described by gauge theory exert forces on each other by the exchange of gauge bosons, usually as virtual particles.-...

 which appears with single and double electric charge

Electric charge

Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...

 and with lepton number

Lepton number

In particle physics, the lepton number is the number of leptons minus the number of antileptons.In equation form,so all leptons have assigned a value of +1, antileptons −1, and non-leptonic particles 0...

 L=+2 and L=-2. It can mediate exotic processes such as V+A muon

Muon

The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...

 decay and muonium

Muonium

Muonium is an exotic atom made up of an antimuon and an electron, which was discovered in 1960 and is given the chemical symbol . During the muon's lifetime, muonium can enter into compounds such as muonium chloride or sodium muonide . Due to the mass difference between the antimuon and the...

-antimuonium conversion. It can also give rise to exotic scattering processes such as electron plus electron goes to muon plus muon which is forbidden in the Standard Model

Standard Model

The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. Developed throughout the mid to late 20th century, the current formulation was finalized in the mid 1970s upon...

. Detailed measurements made at the Paul Scherrer Institute

Paul Scherrer Institute

The Paul Scherrer Institute is a multi-disciplinary research institute which belongs to the Swiss ETH-Komplex covering also the ETH Zurich and EPFL...

 (PSI) have searched for the exotic muon decay and placed a lower bound on the bilepton mass of about 1 TeV. Studies of muonium-antimuonium conversion, also at PSI, have imposed a similar bound. Higher statistics experiments are planned. The bilepton could alternatively be discovered in electron-electron collisions or in multi TeV proton-proton collisions at the Large Hadron Collider

Large Hadron Collider

The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....

.

This particle was at first misnamed "dilepton", with a different pre-existing usage; the present name was introduced in 1996.