The ghosts of matter weigh in Neutrinos have long perplexed both experimental and theoretical physicists

摘要

Once described by physicist Frederick Reines as "the most tiny quantity of reality ever imagined by a human being", neutrinos have long perplexed both experimental and theoretical physicists. Apart from being fiendishly hard to detect, theory suggested these particles are massless, whereas observational evidence hinted at the opposite. So in 1998, when the Super-Kamiokande experiment in Japan obtained the first convincing evidence that neutrinos do indeed have mass, what had been one of the most fundamental puzzles in particle physics was finally settled.