From 1970 to 2009 Yan worked at
Cornell University, in particular the Cornell High-Energy Synchrotron Source and Laboratory for Elementary-Particle Physics (combined into the
Cornell Laboratory for Accelerator-based Sciences and Education as of 2006). He became a professor and in 2010 he reached the status of professor emeritus in physics. Other affiliations during Yan's life and work are: • 1968–1970: research associate at
SLAC • 1973–1974: visiting scientist to SLAC • 1977–1978: scientific associate at
CERN • 1974–1978:
Sloan Fellowship • 1986: visiting chair professor at the physics department of NTU • Since 1991: a fellow of the
American Physical Society • 1991–1992: special chair professor, Institute of Physics, Academia Sinica, ROC • 1997: Director, National Center of Theoretical Sciences, ROC In the 1970s, Yan and
Sidney Drell investigated the important
Drell–Yan process of massive
lepton pair production in
hadronic collisions, which provides a crucial experimental probe into the
parton distribution functions. These describe the way that the
momentum of an incoming high-energy
nucleon is partitioned among its constituent
partons. In the same decade, he pioneered the
Cornell potential, shedding light on the properties of heavy quark–antiquark systems (
charmonium), with
Estia J. Eichten,
Toichiro Kinoshita,
Ken Lane and
Kurt Gottfried. ==Works==