Department of Physics and
Astronomy
presents
The February Jubilee of Physics and Astronomy
A series of public lectures on science and its implications
Martin Perl, 1995 Nobel Laureate in Physics for his discovery of the tau, a much heavier version of the electron, will visit on February 10-12 as the first Walter Selove Distinguished Lecturer in experimental physics. Perl will give a seminar
Searching For Isolated Particles With Fractional Electric Charge
on the search for the isolated fractionally charged particles predicted in some theories of the fundamental particle interactions at 10:30 AM on February 11. His colloquium at 4:00 on the 12th on
Craft and Art in Experimental Science
will emphasize the human and emotional aspects of science which are almost always omitted from sociological, historical and philosophical discussions of scientific research.
Abstracts
Searching
For Isolated Particles With Fractional Electric Charge
10:30 AM, Tuesday, February 11;
David Rittenhouse Laboratory, Room A2
Two premises of the modern theory of elementary particles are: (a) that the only particles with fractional electric charge are quarks, and (b) quarks are bound in hadrons and cannot be individually isolated. The experimental evidence for these premises is broad but not conclusive. Hence we have developed and are using an improved Millikan falling liquid drop method to search for isolated particles with fractional electric charge. Our interest is in such particles that may have been produced in the early universe.
In the talk, various methods which have been used to search for fractional electric charge particles at accelerators, in cosmic rays, and in bulk matter are described. Existing experimental limits are summarized.
Our experiments use a CCD video camera to image
the trajectories of liquid drops falling thru air in the presence of a vertical,
alternating electric field. The images of the trajectories are computer
processed in real time, the electric charge on a drop being measured with
an rms error of 0.025e. This apparatus, our first published results, our
dreams, and our program are explained.
Craft
and Art in Experimental Science
4:00 PM, Wednesday, February 12;
David Rittenhouse Laboratory, Room A1
Martin Perl, 1995 Nobel Laureate in Physics, looks back on his forty years of research in experimental physics to reflect on experimental science as a craft and as an art. His reflections, illustrated with slides, emphasize the human and emotional aspects of science which are almost always omitted from sociological, historical and philosophical discussions of scientific research. Among his topics are:
[ Jubilee | Harrison Schmitt | Martin Perl | Supernova 1987A ]
Paul Langacker (pgl@langacker.hep.upenn.edu)
Last updated 1/18/97