Toni Ziegler - University of Wisconsin Madison. http://www.primate.wisc.edu/wprc/faculty/ziegler.html
There are actually quite a few people dong marmoset research at UW.
A Google search: "primate AND researcher AND marmoset" will return tons of papers which will then give you researcher names and affiliations. You may want to narrow the search by a specific behavioral topic as behavior is a huge body of literature.