Word: meson
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Dates: during 1960-1969
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Center of the scientific storm is a subatomic particle called the eta meson, which lives for only a billionth of a billionth of a second before breaking down into three smaller particles called pions-one positive, one negative, one without any electrical charge. According to the laws of symmetry, the positive and negative pions should have identical energies. But when a team led by Columbia University's Dr. Paolo Franzini examined 1,441 photographs of eta-meson decay in the Brookhaven bubble chamber (TIME, July 8), they found that in 53% of the photographs the positive pion apparently...
Reversing the Field. In their experiment at Geneva, the European physicists also studied eta-meson decay. They analyzed 10,665 photographs of tracks made by pions in the CERN spark chamber, and in their larger, more reliable statistical sample, they found no significant difference in the energy levels of positive and negative pions...
...Brookhaven experiment involved a fast-decaying subatomic particle known as an eta meson, which breaks down into three lighter particles known as pions-one with no electrical charge. According to the theory of symmetry, the positive and negative pions should not have shown any significant difference in speed. But 53% of the time, the positive pion zipped across the bubble chamber with more energy than its negative antiparticle...
This was just what Columbia's Dr. Paolo Franzini had in mind when he went to work with Brookhaven's synchrotron in January 1965. Along with his wife, Dr. Juliet Lee-Franzini, Drs. Charles Baltay and Lawrence Kirsch, he fired particles called pi mesons into a bubble chamber filled with liquid deuterium. About one-thirtieth of the times that a pi meson hit a deuterium nucleus, out came the eta meson, which decays into three pions. The pions streaked through the bubble chamber, the positive leaving a line that curved to the right, the negative peeling...
...clear enough: a particle must exist that has a negative electric charge and a mass- of 1,676 million electron volts. It should have a life span of one ten-billionth of a second after it is formed, and then decay into a xi particle and a pi-meson...