particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...

, V was a generic name for heavy, unstable subatomic particles that decay into a pair of particles, thereby producing a characteristic letter V in a

bubble chamber A bubble chamber is a vessel filled with a superheated transparent liquid (most often liquid hydrogen) used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded the 1 ...

or other

particle detector In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nu ...

. Such particles were first detected in

cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

interactions in the atmosphere in the late 1940s and were first produced using the

Cosmotron The Cosmotron was a particle accelerator, specifically a proton synchrotron, at Brookhaven National Laboratory. Its construction was approved by the U.S. Atomic Energy Commission in 1948, reaching its full energy in 1953, and continuing to r ...

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle ...

Brookhaven National Laboratory Brookhaven National Laboratory (BNL) is a United States Department of Energy national laboratory located in Upton, Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base and Japanese internment c ...

in the 1950s. Since all such particles have now been identified and given specific names, for instance

Kaon KAON (Karlsruhe ontology) is an ontology infrastructure developed by the University of Karlsruhe and the Research Center for Information Technologies in Karlsruhe. Its first incarnation was developed in 2002 and supported an enhanced version of ...

s or Sigma baryons, this term has fallen into disuse. V⁰ is still used on occasion to refer generally to

neutral particle In physics, a neutral particle is a particle with no electric charge, such as a neutron. The term ''neutral particles'' should not be confused with '' truly neutral particles'', the subclass of neutral particles that are also identical to their o ...

s that may confuse the

B-tagging b-tagging is a method of jet flavor tagging used in modern particle physics experiments. It is the identification (or "tagging") of jets originating from bottom quarks (or b quarks, hence the name). Importance b-tagging is important because: * ...

algorithms in a modern particle detector, as is used in Section 7 o
this ATLAS conference note

References

* * Subatomic particles {{particle-stub