Annihilation

[1] The total energy and momentum of the initial pair are conserved in the process and distributed among a set of other particles in the final state.

Otherwise, the process is understood as the initial creation of a boson that is virtual, which immediately converts into a real particle + antiparticle pair.

When a low-energy electron annihilates a low-energy positron (antielectron), the most probable result is the creation of two or more photons, since the only other final-state Standard Model particles that electrons and positrons carry enough mass–energy to produce are neutrinos, which are approximately 10,000 times less likely to produce, and the creation of only one photon is forbidden by momentum conservation—a single photon would carry nonzero momentum in any frame, including the center-of-momentum frame where the total momentum vanishes.

The inverse process, pair production by a single real photon, is also possible in the electromagnetic field of a third particle.

The newly created mesons are unstable, and unless they encounter and interact with some other material, they will decay in a series of reactions that ultimately produce only photons, electrons, positrons, and neutrinos.

[4] Similar reactions will occur when an antinucleon annihilates within a more complex atomic nucleus, save that the resulting mesons, being strongly interacting, have a significant probability of being absorbed by one of the remaining "spectator" nucleons rather than escaping.

In 2012, the CERN laboratory in Geneva announced the discovery of the Higgs in the debris from proton–proton collisions at the Large Hadron Collider (LHC).

The strongest Higgs yield is from fusion of two gluons (via annihilation of a heavy quark pair), while two quarks or antiquarks produce more easily identified events through radiation of a Higgs by a produced virtual vector boson or annihilation of two such vector bosons.