ZZ diboson
Encyclopedia
ZZ dibosons are rare pairs of Z bosons that are extremely difficult to detect. They were first observed by the scientists of DØ collaboration at Fermilab
. They are force-carrying particles
produced in proton
–antiproton
collisions at the Tevatron
, the world’s second highest-energy particle accelerator
(after the CERN
Large Hadron Collider
). The observation of the ZZ dibosons was announced at a Fermilab seminar on 30 July 2008.
The rarest diboson processes after ZZ dibosons are those involving the Higgs boson
, so seeing ZZ diboson is an essential step in demonstrating the ability to see the Higgs boson. ZZ dibosons are the latest in a series of observations of pairs of gauge bosons (force-carrying particles) by DØ and its sister experiment CDF
(also at Tevatron).
Final analysis of the data for this discovery was done by a team of international researchers including scientists of American, Belgian, British, Georgian, Italian, and Russian nationalities. The observations began with the study of the already-rare production of W bosons plus photon
s ; then Z bosons plus photons ; then observation of W pairs ; then a mix of W and Z boson . The ZZ is the most massive combination and thus has the lowest predicted likelihood of production in the Standard Model
.
Fermilab
Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...
. They are force-carrying particles
Force carrier
In particle physics, quantum field theories such as the Standard Model describe nature in terms of fields. Each field has a complementary description as the set of particles of a particular type...
produced in proton
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
–antiproton
Antiproton
The antiproton is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived since any collision with a proton will cause both particles to be annihilated in a burst of energy....
collisions at the Tevatron
Tevatron
The Tevatron is a circular particle accelerator in the United States, at the Fermi National Accelerator Laboratory , just east of Batavia, Illinois, and is the second highest energy particle collider in the world after the Large Hadron Collider...
, the world’s second highest-energy particle accelerator
Particle accelerator
A particle accelerator is a device that uses electromagnetic fields to propel charged particles to high speeds and to contain them in well-defined beams. An ordinary CRT television set is a simple form of accelerator. There are two basic types: electrostatic and oscillating field accelerators.In...
(after the CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
Large Hadron Collider
Large Hadron Collider
The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....
). The observation of the ZZ dibosons was announced at a Fermilab seminar on 30 July 2008.
The rarest diboson processes after ZZ dibosons are those involving the Higgs boson
Higgs boson
The Higgs boson is a hypothetical massive elementary particle that is predicted to exist by the Standard Model of particle physics. Its existence is postulated as a means of resolving inconsistencies in the Standard Model...
, so seeing ZZ diboson is an essential step in demonstrating the ability to see the Higgs boson. ZZ dibosons are the latest in a series of observations of pairs of gauge bosons (force-carrying particles) by DØ and its sister experiment CDF
CDF
-Mathematics, science, and computers:* .cdf , the ANDI/netCDF mass spectrometry data interchange file format* Channel Definition Format, an XML standard* Charging Data Function, in the Session Initiation Protocol standard...
(also at Tevatron).
Final analysis of the data for this discovery was done by a team of international researchers including scientists of American, Belgian, British, Georgian, Italian, and Russian nationalities. The observations began with the study of the already-rare production of W bosons plus photon
Photon
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
s ; then Z bosons plus photons ; then observation of W pairs ; then a mix of W and Z boson . The ZZ is the most massive combination and thus has the lowest predicted likelihood of production in the Standard Model
Standard Model
The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. Developed throughout the mid to late 20th century, the current formulation was finalized in the mid 1970s upon...
.
See also
- DineutronDineutronA dineutron is a hypothetical particle consisting of two neutrons that was suggested to have a transitory existence in nuclear reactions produced by helions that result in the formation of a proton and a nucleus having the same atomic number as the target nucleus but a mass number two units greater...
- DiprotonDiprotonA diproton is a hypothetical isotope of helium nucleus consisting of two protons and no neutrons, and is predicted to be less stable than 5He...
- Pauli exclusion principlePauli exclusion principleThe Pauli exclusion principle is the quantum mechanical principle that no two identical fermions may occupy the same quantum state simultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles...
- Higgs bosonHiggs bosonThe Higgs boson is a hypothetical massive elementary particle that is predicted to exist by the Standard Model of particle physics. Its existence is postulated as a means of resolving inconsistencies in the Standard Model...
- List of particles
External links
- Fermilab Press Release
- Photos and graphics
- Diboson Physics at CDF by Anna Sfyrla