particle physics Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...

, exotic baryons are a type of

hadron In particle physics, a hadron is a composite subatomic particle made of two or more quarks held together by the strong nuclear force. Pronounced , the name is derived . They are analogous to molecules, which are held together by the electri ...

(bound states of quarks and

gluons A gluon ( ) is a type of massless elementary particle that mediates the strong interaction between quarks, acting as the exchange particle for the interaction. Gluons are massless vector bosons, thereby having a spin of 1. Through the s ...

) with half-integer spin, but with a quark content different from the three quarks (''qqq'') present in conventional baryons. 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 bar ...

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 a particle physics detector collecting data at the Large Hadron Collider at CERN. LHCb specializes in the measurements of the parameters of CP violation in the interactions of b- and c-hadro ...

collaboration. Several types of exotic baryons that require physics beyond the

Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

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 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, entrepreneur, futurist, and inventor. He is involved in fields such as optical character recognition (OCR), speech synthesis, text-to-speech synthesis, spee ...

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 chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8: each oxygen atom has 8 protons in its ...

s composed of exotic baryons that would eventually constitute a new periodic table of elements 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