- Hyperon
In
particle physics , a hyperon is anybaryon containing astrange quark , but nocharm quark s orbottom quark s.Properties and behavior of hyperons
Being baryons, all hyperons are
fermion s. That is, they havehalf-integer spin and obeyFermi-Dirac statistics . They all interact via thestrong nuclear force , making them types ofhadron . They are composed of three lightquark s, at least one of which is astrange quark , which makes them strange baryons. Hyperons decay weakly with non-conserved parity.Types of hyperons
There are three Sigma hyperons, SubatomicParticle|Sigma+, SubatomicParticle|Sigma0 and SubatomicParticle|Sigma-. They have rest energies of ~val|1190|u=MeV and lifetimes of ~val|1|e=-10|u=s with the exception of SubatomicParticle|Sigma0 whose lifetime is shorter than val|10|e=-14|u=s.
There is one Lambda hyperon, SubatomicParticle|Lambda0. It has a rest energy of val|1115|u=MeV with a lifetime of val|2.6|e=-10|u=s.
There are two Xi hyperons, SubatomicParticle|Xi0 and SubatomicParticle|Xi-. They have rest energies of val|1315|u=MeV and val|1320|u=MeV and lifetimes of val|2.9|e=-10|u=s and val|1.6|e=-10|u=s.
There is one Omega hyperon, the last discovered, SubatomicParticle|Omega-, with a mass of val|1670|u=MeV and a lifetime of val|8.2|e=-11|u=s.
Hyperon decay
Since
strangeness is conserved by thestrong interaction s, the ground-state hyperons cannot decay strongly. However, they do participate in strong interactions.Λ decay
SubatomicParticle|Lambda0 may also decay on rare occurrences via these processes
Σ decay
Ξ decay
SubatomicParticle|Xi particles are also known as "cascade" hyperons, since they go through a two-step cascading decay into a nucleon by first decaying to a SubatomicParticle|Lambda0 and emitting a SubatomicParticle|Pion+-.
Ω− decay
The SubatomicParticle|Omega- has a
baryon number of +1 andhypercharge of -2 giving it strangeness of −3.It takes multiple flavor-changing weak decays for it to decay into a proton or neutron.Murray Gell-Mann 's SU(3) model (sometimes called the Eightfold Way) predicted this hyperon's existence, mass and that it will only undergo weak decay processes.Experimental evidence for its existence was discovered in 1964 at
Brookhaven National Laboratory . Further examples of its formation and observation usingparticle accelerator s confirmed the SU(3) model.Hyperon research
The first research into hyperons happened in the 1950s, and spurred physicists on to the creation of an organized classification of particles. Today, research in this area is carried out on data taken at many facilities around the world, including
CERN ,Fermilab ,SLAC , JLAB,Brookhaven National Laboratory ,KEK , and others. Physics topics include searches forCP violation , measurements of spin, studies ofexcited state s (commonly referred to as "spectroscopy"), and hunts for exotic states such aspentaquark s anddibaryon s.List of hyperons
ee also
*
Delta baryon
*Hypernucleus
*Lambda baryon
*List of mesons
*List of particles
*Nucleon
*Omega baryon
*Physics portal
*Sigma baryon
*Timeline of particle discoveries
*Xi baryon References
*
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