V particle

In particle physics, 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 or other particle detector. Such particles were first detected in cosmic ray interactions in the atmosphere in the late 1940s ^[1] and were first produced using the Cosmotron particle accelerator at Brookhaven National Laboratory in the 1950s.^[2] Since all such particles have now been identified and given specific names, such as K meson or Sigma baryon, this term has fallen into disuse.

V⁰ is still used on occasion to refer generally to neutral particles that may confuse the B-tagging algorithms in a modern particle detector, as is used in Section 7 of this ATLAS conference note.

References

• Alford, W. L. (1953). The Mean Lifetime of V-Particles (PDF) (Thesis). California Institute of Technology. 
• Shelton, F. H. (1953). V-Particle Production (PDF) (Thesis). California Institute of Technology.