NEUTRINO HUNTERS

An astrophysicist explains why scientists are eager to learn more about the elusive, “pathologically shy” neutrino.

“[N]eutrinos are the most abundant matter particles in the universe,” writes Jayawardhana (Observational Astrophysics/Univ. of Toronto; Strange New Worlds: The Search for Alien Planets and Life beyond Our Solar System, 2011, etc.). “[A]bout a hundred-trillion neutrinos produced in the nuclear furnace at the Sun's core pass through your body every second…yet they do no harm and leave no trace.” The author traces their discovery to the dawn of the quantum age, when the release of radioactive materials appeared to challenge conservation of energy. In 1930, physicist Wolfgang Pauli suggested the existence of a putative, still-undetected particle (the neutrino) as a way to balance the energy equation. At that time, only three elementary particles (the proton, the electron and the photon) were known. With the discovery of the neutron, the role of the neutrino in transformations between neutrons and protons became clearer. Jayawardhana explains that despite the fact that fission and fusion release “staggering bursts of these particles,” their experimental verification only became possible as an outgrowth of the effort to produce an atomic bomb in the days leading up to World War I. “Since then,” he writes, “we have realized that the shy neutrinos hold the key to unraveling a great many cosmic mysteries.” Further experiments led to new anomalies and the recognition that the ghostly neutrino was not, as first thought, without mass. Today, we may now be on the verge of “solving the great mystery of how matter came to dominate the universe.”

Jayawardhana includes a fascinating account of the disputes between the theorists and experimentalists in this epic scientific adventure story with—as of yet—no last chapter.