Physics Department News Archive

October 26, 2006

Particle Decays into Z + Photon Unlikely

Batavia, IL - Our current understanding of the universe includes four forces: gravity, electromagnetism, the strong force, and the weak force. Particle physics provides, through the standard model, explanations of three of these forces. The electromagnetic force is carried (propagated) by photons; the strong force is carried by gluons; and the weak force is carried by Z and W bosons. Gravity, however, has so far not been successfully incorporated into the standard model, indicating that our understanding of the fundamental forces is incomplete. New experimental results, such as the detection of new particles not predicted by the standard model, are therefore interesting, as they might provide clues as to why we do not understand the gravitational force.

Augustana College Assistant Professor Drew Alton is the primary author of a new publication from the D0 collaboration at FermiLab that places stringent new limits on one possible decay mode of several new particles. In a search for particles decaying into a Z boson and a photon, no evidence was found for particles with mass above 100 GeV/c 2 . This result places limits on theoretical predictions that go beyond the standard model.

The results are published in the current issue of Physics Letters B.

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