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Quantum Bull's-Eye: Particle-mass prediction hits the mark

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.

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