Word: neutrinos
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Since 1968 scientists have been monitoring huge detectors for signs of these fleeting visitors from the sun. But so far, the results have been both disappointing and intriguing: the experiments have detected far fewer neutrinos than solar models predicted. Scientists were especially baffled by a recent report from a Soviet-American research team that set up a detector to monitor neutrinos emitted by the fusion of hydrogen atoms, the sun's main reaction. After four months of operation near the Soviet town of Baksan, the experiment has yet to turn up a single solar neutrino...
...case of the missing solar neutrinos has stirred growing excitement in the physics world. There are three possibilities: the Baksan experiment is wildly wrong, scientists don't understand the sun as well as they thought they did, or scientists have underestimated the elusiveness of the neutrino. The answer to the mystery could have profound implications for physicists' understanding of the universe. Two eminent theorists, John Bahcall of the Institute for Advanced Study in Princeton, N.J., and Cornell University's Hans Bethe have co-authored a paper that elaborates on an intriguing solution to the puzzle: neutrinos escape detection by changing...
...basic "family" of particles is supplemented by two more exotic families, each of which has a parallel structure: two quarks, a type of electron and a type of neutrino. These two extra families are all but extinct in the modern universe, but they apparently existed in the searing heat of the Big Bang, and only accelerators can re-create them. In fact, all of the quarks in all of the families have been found or re-created -- except for the one called the top, which is believed to be the heaviest of all (its mass is at least 90 times...
...familiar with can be subsumed within one family of particles. This family includes the common electron, which hovers around the nucleus of the atom; the "up" and "down" varieties of quarks, now known to be the constituents of protons and neutrons; and an obscure particle known as the electron neutrino. Neutrinos have no charge and no measured mass, yet are thought to be among the most abundant particles in the universe...
Physicists had long speculated about the existence of neutrinos, particles that appear in all radioactive processes. Because the elusive neutrino is essentially without mass or charge, it was difficult to pin down. Lederman calculates that a single neutrino has only a fifty-fifty chance of being deflected when streaming through 100 million miles of solid steel. The young physicists used the powerful accelerator in Brookhaven, L.I., to produce and aim a flood of protons at a beryllium metal target. The stupendous collisions of protons slamming into the barrier shattered atomic nuclei, releasing new particles, including neutrinos. The particles then...