•
Cosmon, hypothetical state containing the observable universe before the
Big Bang. Observed, but without sufficient evidence. •
Diquark, hypothetical state of two
quarks grouped inside a
baryon. •
Geons, electromagnetic or gravitational waves which are held together in a confined region by the gravitational attraction of their own field of energy. •
Kaluza–Klein towers of particles, predicted by some models of extra dimensions. The extra-dimensional momentum is manifested as extra mass in four-dimensional spacetime. •
Pomerons, used to explain the
elastic scattering of hadrons and the location of
Regge poles in
Regge theory. A counterpart to
odderons. •
True muonium, atom composed of a
muon and an anti-muon. Yet unobserved.
By type •
Branons, scalar fields predicted in brane world models. •
Composite Higgs, models that consider the
Higgs boson to be a composite particle. •
Higgs doublets are hypothesized by some theories of
physics beyond the Standard Model. •
Continuous spin particle are hypothetical massless particles related to the classification of the representations of the
Poincaré group. •
Cryptons, any particle from the dark sector of
string theory landscape. • Elementary particles that are not bosons or fermions: • Paraparticles, exotic particles that can survive in a 3D-space and follow
parastatistics •
Plektons, particles that follow
Braid statistics •
Exotic particles, particles with exotic properties like negative mass or complex mass. •
Exotic hadrons, particles composed of unusual combinations of quarks and gluons. •
Exotic mesons •
Exotic baryons •
Glueball, hypothetical particle that consist of only
gluons. • Quark bound states beyond the
pentaquark, like
hexaquarks and
heptaquarks. •
Leptoquark, hypothetical particles that are neither bosons or fermions but carry
lepton and
baryon numbers. •
Magnetic monopole is a generic name for particles with non-zero magnetic charge. They are predicted by Grand Unification Theories. These may include: •
Dirac monopoles, monopole that would allow charge quantization. •
't Hooft–Polyakov monopoles, Dirac monopole but without
Dirac strings. •
Wu–Yang monopoles, point-like monopole with potential of the form 1/
r. •
Dyons, extensions of the idea of a magnetic monopole. •
Majorana fermions, fermions that are their own anti-particle •
Mesonic molecule, two mesons bound together by strong force. •
Micro black hole, sub-atomic sized black holes. •
Black hole electron, microscopic black hole with the properties of an electron. •
Virtual black hole, microscopic black holes produced by fluctuations of space-time •
Minicharged particle are hypothetical subatomic particles charged with a tiny fraction of the electron charge. •
Mirror particles are predicted by theories that restore
parity symmetry. •
Neutronium, hypothetical nuclei consisting only of
neutrons (more than one). Examples include the
tetraneutron. •
Primons, particles with statistics related to the distribution of
prime numbers •
Preons were suggested as subparticles of quarks and leptons, but modern
collider experiments have all but ruled out their existence. • Rishons, particles from the
Rishon model of preons. • From superseded and obsolete theories •
Caloric rays used until the 19th century to explain
thermal radiation. •
Light corpuscles, hypothetical classical particles used to explain optical phenomena. •
Phlogiston, hypothetical combustible content in matter used to explain
thermodynamics before the 18th century. • Ultramundane corpuscles, from
Le Sage's theory of gravitation, used to explain gravitational phenomena. •
Strangelet, hypothetical particle that could form matter consisting of
strange quarks. •
R-hadron, bound particle of a quark and a supersymmetric particle. •
T meson, hypothetical
mesons composed of a
top quark and one additional subatomic particle. Examples include the
theta meson, formed by a top and an anti-top. •
Tachyons is a hypothetical particle that travels
faster than the speed of light so they would paradoxically experience time in reverse (due to inversion of the
theory of relativity) and would violate the known laws of
causality. A tachyon has an
imaginary rest mass. •
Unparticles, hypothetical particles that are massless and scale invariant. •
Weyl fermions, hypothetical spin-1/2 massless particles, only found as a
quasiparticle. == See also ==