I will talk about the work that I did with Roberto Peccei in 1976 that led to the idea of the QCD  axion, now a popular candidate for the particle that composes dark matter.

New ideas seldom arise in finished form, but the published record typically only gives us the completed result. I use this example to stress the importance of incomplete and partially wrong ideas, and how we learn from them.  I will also talk about the importance of early and long term efforts to search for such particles, and how this work contributes to the current popularity of the idea even as it begins to rule out some mass regions for such particles.

Helen Quinn is an Australian-born theoretical particle physicist and professor emerita at Stanford University and SLAC National Accelerator Laboratory. She earned her Ph.D. from Stanford in 1967 and has been widely honored for her contributions to particle physics, including work on the Peccei-Quinn symmetry and unified theories, as well as major awards like the Dirac Medal and the Sakurai Prize. Since retiring in 2010, she has been a prominent leader in science education reform, helping shape national K-12 science standards and championing physics outreach and education initiatives.

Eugene Feenberg (1906-1977) was a pioneering theoretical physicist whose work laid important foundations for the modern quantum many-body theory. A longtime member of the Washington University in St. Louis faculty, Feenberg made influential contributions to nuclear physics, quantum mechanics, and the theory of strongly interacting systems, and is especially recognized as a founder of correlated basis function theory. The Eugene Feenberg Memorial Lecture Series honors his legacy and his lasting impact as a scholar, mentor, and teacher by bringing leading physicists to campus to highlight ongoing advances in the field.