Report hints at the existence of a new and massive elementary particle In a weak moment, researchers have found an unexpected asymmetry in particle production that could hint at exotic physics. The tentative evidence, announced August 21, could be the fingerprint of a massive elementary particle that would help unify three of the four known forces in nature. The physicists collected data for nearly a decade at the Belle particle accelerator experiment in Tsukuba, Japan. In the experiment, known as a B factory, beams of electrons and positrons collide to produce millions of pairs of B mesons and anti-B mesons....