SEARCHING FOR FRACTIONAL CHARGE ELEMENTARY PARTICLES IN METEORITIC

Motivation: All known elementary particles that can be isolated such as electrons, photons, and protons, have an electric charge given by nq where n is an integer, including 0, and q is the magnitude of the electron charge. (Quarks have fractional charge such as q/3 and 2q/3, but it is believed that quarks are always bound in other particles such as protons, and cannot be isolated.) There is no understanding of the observed rule that the charges of elementary particles that can be isolated are restricted to nq, hence this rule is simply built into modern elementary particle theory. For a number of years we have been testing this rule by searching for fractional electric charge in terrestrial, bulk matter, the anomalous charge assumed to come from the presence of fractional charge stable particles produced in the early universe. We have not found such particles. Meteoritic Material: There are geochemical and astrophysical reasons why fractional charge particles could exist in much greater abundance in some types of asteroidal material compared to accessible terrestrial materials. Therefore we have just begun a search using material from the Allende meteorite. Experimental Method: We use a modern variation of the Millikan oil drop method, in which a CCD camera and computer system records the trajectory of drops falling through an oscillating, horizontal electric field. The drops produced by our own design of a drop-on-demand ejector are about 20 µm in diameter. The charge on each drop is measured with an accuracy of about 1/30 of an electron charge. The drops consist of a semi-stable suspension of ground meteorite in mineral oil. I will describe the apparatus, the drop ejector and the method of making meteorite-oil suspension. Since we are novices in meteoritical science we welcome suggestions and comments about our first foray into that science.