Stable, Doubly Heavy Tetraquark Mesons (Colloquium)
Nico van Kampen Colloquium presented at the University of Utrecht, April 4, 2018. (One typo corrected in version 2.)
General physics colloquium version. Research support: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.