Correct calculation strengthens theory of quark-gluon interactions in nuclear particles When it comes to weighty matters, quarks and gluons rule the universe, a new study confirms. One of the largest computational efforts to calculate the masses of protons and neutrons shows that the standard model of particle physics predicts those masses with an uncertainty of less than 4 percent. Christian Hoelbling, affiliated with the Bergische Universtät Wuppertal in Germany, the Eötvös University in Budapest and the CNRS in Marseille, France, and his colleagues report their findings in the Nov. 21 Science. Nearly all the mass of ordinary matter consists of...