Quarks, the basic constituents of much of matter, are so complicated that scientists have been unable to apply fundamental theory to precisely predict the mass of a quark-containing particle. Until now.
In the May 6 Physical Review Letters, researchers report their theoretical prediction of the mass of the rare particle known as the Bc meson, and that prediction agrees to within a few tenths of a percent with a not-yet-published experimental determination of the mass. The unprecedented match suggests that after a quest of more than 30 years, physicists may have finally fine-tuned a computational tool known as lattice quantum chromodynamics (QCD) so that it's equal to the challenge of quark physics.
"This is by far the most dramatic confirmation to date that [lattice QCD] can deliver the long-promised precision," comments experimentalist Ian P. Shipsey of Purdue University in West Lafayette, Ind.