Exotic baryons are a type of
hadron
In particle physics, a hadron (; grc, ἁδρός, hadrós; "stout, thick") is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the ele ...
(bound states of
quarks
A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly ...
and
gluons
A gluon ( ) is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks. It is analogous to the exchange of photons in the electromagnetic force between two charged particles. Gluons bind qua ...
) with
half-integer spin, but with a quark content different from the three quarks (''qqq'') present in conventional
baryons
In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classifie ...
. An example would be
pentaquark
A pentaquark is a human-made subatomic particle, consisting of four quarks and one antiquark bound together; they are not known to occur naturally, or exist outside of experiments specifically carried out to create them.
As quarks have a bary ...
s, consisting of four quarks and one antiquark (''qqqqq̅'').
So far, the only observed exotic baryons are the pentaquarks , discovered in 2015,
in 2019 and in 2022 by the
LHCb
The LHCb (Large Hadron Collider beauty) experiment is one of eight particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parame ...
collaboration.
Several types of exotic baryons that require physics beyond the
Standard Model
The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. I ...
have been conjectured in order to explain specific experimental anomalies. There is no independent experimental evidence for any of these particles. One example is
supersymmetric
In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of supersymmetric theorie ...
R-baryons, which are bound states of 3 quarks and a
gluino. The lightest R-baryon is denoted as S and consists of an up quark, a down quark, a strange quark and a gluino. This particle is expected to be long lived or stable and has been invoked to explain ultra-high-energy cosmic rays. Stable exotic baryons are also candidates for
strongly interacting dark matter.
It has been speculated by
futurologist Ray Kurzweil
Raymond Kurzweil ( ; born February 12, 1948) is an American computer scientist, author, inventor, and futurist. He is involved in fields such as optical character recognition (OCR), text-to-speech synthesis, speech recognition technology, and ...
that by the end of the 21st century it might be possible by using
femtotechnology to create new
chemical element
A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
s composed of exotic baryons that would eventually constitute a new
periodic table of elements
The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of ch ...
in which the elements would have completely different properties than the regular chemical elements.
[ Kurzweil, Ray '' The Age of Spiritual Machines'' 1999]
References
{{Authority control
Baryons
Hypothetical composite particles