Antimatter may seem the stuff of science fiction but it is indeed very real substance, made in our laboratories though rare in our Universe. The deep puzzle is that the laws of physics for antimatter are almost identical to the laws for matter, so how and when in the history of the Universe did the imbalance between them develop? (Note that if no such imbalance had occurred we would not be here to talk about it; the Universe today would contain no stars, no planets, no people. ) I will discuss what little we know about the answer to this question, how we know it, and what we can do to try to understand more.

Helen Quinn was born in Australia. She attended primary and high school in Victoria and started her undergraduate studies at the University of Melbourne before transferring to Stanford University. She received her Ph.D. from Stanford in 1967 and then held a postdoctoral position at the German Synchrotron Laboratory in Hamburg, Germany. She next spent seven years at Harvard University before returning to Stanford where she is now a Professor of Physics at the Stanford Linear Accelerator Center.

Some Important Contributions: Working with Howard Georgi and Steven Weinberg Helen showed how the three types of particle interactions (strong, electromagnetic, and weak) which look very different as we see their impact in the world around us become very similar in extremely high energy processes and so can possibly be viewed as three aspects of a single unified force. Suggested a possible near symmetry of the universe (now known as Peccei- Quinn symmetry) to explain how strong interactions can maintain the symmetry between particles and antiparticles (matter and antimatter) when weak interactions do not. One consequence of this theory is a particle known as the axion which has yet to be observed but is possibly the dark matter that pervades the Universe. (There is more than ten times more mass in dark matter in space than in all the stars.) Showed how physics of quarks can be used to predict certain aspects of the physics of hadrons (which are particles made from quarks) without knowng the details of the hadron's structure (with Enrico Poggio and Steven Weinberg). This useful property is now known as quark-hadron duality.

Honors: Fellow and Past President, American Physical Society Fellow of the American Academy of Arts and Sciences Member of the US National Academy of Sciences 2000 Dirac Medal of the International Center for Theoretical Physics, Trieste, Italy (with Howard Georgi and Jogesh Pati) for pioneering contributions to the quest for a unified theory of quarks and leptons and of the strong, weak, and electromagnetic interactions

When not working on sub atomic particles, Helen works with primary and high school teachers in California to make physics fun and exciting for students. Together with Professor Yosef Nir of the Weizmann Institute (Israel) she is working on a book for the general public with the same title as this lecture. She has given many public talks on this topic.

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Further information is available from: Dr Marc Duldig, ph. (03) 6232 3333,

e-mail: Marc.Duldig@aad.gov.au or Dr Elizabeth Chelkowska, ph. (03) 6226 2725,

e-mail: Elizabeth.Chelkowska@utas.edu.au.