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In particle physics, annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron to produce two photons. The total energy and momentum of the initial pair are conserved in the process and distributed among a set of other particles in the final state. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of such an original pair are zero. Hence, any set of particles may be produced whose total quantum numbers are also zero as long as conservation of energy, conservation of momentum, and conservation of spin are obeyed.
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The
J/ψ
(J/psi) meson is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium" or psions. The
J/ψ
is the most common form of charmonium, due to its spin of 1 and its low rest mass. The
J/ψ
has a rest mass of 3.0969 GeV/c2, just above that of the
η
c, and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected.
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John William Harris is an American experimental high energy nuclear physicist and D. Allan Bromley Professor of Physics at Yale University. His research interests are focused on understanding high energy density QCD and the quark–gluon plasma created in relativistic collisions of heavy ions. Dr. Harris collaborated on the original proposal to initiate a high energy heavy ion program at Cern in Geneva, Switzerland, has been actively involved in the CERN heavy ion program and was the founding spokesperson for the STAR collaboration at RHIC at Brookhaven National Laboratory in the U.S.
Olga Evdokimov is a Russian born professor of physics at the University of Illinois, Chicago (UIC). She is a High Energy Nuclear Physicist, who currently collaborates on two international experiments; the Solenoidal Tracker At RHIC (STAR) experiment at the Relativistic Heavy Ion Collider (RHIC), Brookhaven National Laboratory, Upton, New York and the Compact Muon Solenoid (CMS) experiment at the LHC, CERN, Geneva, Switzerland.
Claude Pruneau is a Canadian-American experimental high-energy nuclear physicist. He is a Professor of Physics at Wayne State University and the author of several books. He is best known for his work on particle correlation measurements in heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.
Reinhard Stock is a German experimental physicist, specializing in heavy-ion physics.
References
- ↑ D. H. Perkins (2000). Introduction to High Energy Physics, Cambridge University Press.
- ↑ Gross, David J.; Wilczek, Frank (25 June 1973). "Ultraviolet Behavior of Non-Abelian Gauge Theories". Physical Review Letters. 30 (26): 1343–1346. Bibcode:1973PhRvL..30.1343G. doi: 10.1103/physrevlett.30.1343 .
- ↑ Adcox, K.; et al. (PHENIX Collaboration) (2002). "Suppression of Hadrons with Large Transverse Momentum in Central Au+Au Collisions at √sNN = 130 GeV". Physical Review Letters. 88 (2): 022301. arXiv: nucl-ex/0109003 . doi:10.1103/physrevlett.88.022301. PMID 11801005. S2CID 119347728.
- 1 2 Adler, C.; et al. (STAR Collaboration) (26 February 2003). "Disappearance of Back-To-Back High-pT Hadron Correlations in Central Au + Au Collisions at √sNN = 200 GeV". Physical Review Letters. 90 (8): 082302. arXiv: nucl-ex/0210033 . doi:10.1103/physrevlett.90.082302. PMID 12633419. S2CID 41635379.
- ↑ "LHC experiments bring new insight into primordial universe" (Press release). CERN. November 26, 2010. Retrieved December 2, 2010.
- ↑ Aad, G.; et al. (ATLAS Collaboration) (13 December 2010). "Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions at √sNN = 2.76 TeV with the ATLAS Detector at the LHC". Physical Review Letters. 105 (25): 252303. doi: 10.1103/physrevlett.105.252303 . PMID 21231581.
- ↑ Chatrchyan, S.; et al. (CMS Collaboration) (12 August 2011). "Observation and studies of jet quenching in Pb-Pb collisions at √sNN = 2.76 TeV". Physical Review C. 84 (2): 024906. doi: 10.1103/physrevc.84.024906 . hdl: 1721.1/67342 .
- ↑ CERN (18 July 2012). "Heavy ions and quark-gluon plasma".
