Click on the picture to view the original at the Fermilab E866 page.
The Meson Cloud Project is a group of undergraduate students working under the direction of Dr. Mary Alberg of the Seattle University Physics Department. We are investigating the asymmetric light antiquark distributions of the proton and looking at various quark-meson models to explain the asymmetry.
These pages are maintained by students and are always under development. Please come back as they are updated.
Ordinary matter is composed of protons, neutrons, and electrons. Of these, the electron appears to be a fundamental particle called a Lepton. The proton and neutron, however, are composed of yet smaller particles called quarks which are in turn held together by the strong force, mediated by gluons. Specifically, the proton (uud) contains two up quarks (u) and one down quark (d). The neutron (udd) is composed of two down quarks and one up quark.
In addition to the valence quarks (uud in the case of the proton), quark-antiquark pairs are constantly being created and destroyed within the proton. These q-qbar pairs (up-antiup, down-antidown, etc. ) are part of the proton "sea." Because the up and down quarks are approximately equal in mass, statistically they should be created in approximately equal numbers. However, recent experiments have shown that there are many more down antiquarks than up antiquarks within the proton sea. The Meson Cloud Project is working towards an explanation of this light antiquark flavor asymmetry by developing a more complete meson-cloud model.
Click here for a more complete introduction to the E866/NuSea Experiment.
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These pages were last modified 5.December, 2001 by Steven Troy.