Hunch

Experimental physicists have found that the electron has an intrinsic mass or "weight" of about .0000000000000000000000000009 gram. This quantity is usually represented by the convenient symbol m. Both experimental and mathematical physicists have regarded m as a major constant of nature, a foundation stone of the universe.

Last week as hundreds of the nation's scientists journeyed home from the midwinter convention of the American Association for the Advancement of Science, physicists were excited and disturbed because doubt had been cast on the constancy of m. The doubter was Professor George Eric MacDonnell Jauncey of Washington University (St. Louis). In a specially arranged speech after the close of the meeting, he urged that m be considered a variable, offered experiments to back up his view.

In recent months Carl David Anderson of California Institute of Technology has been experimenting with a peculiar particle which showed up in the cosmic rays reaching earth. It appeared that this "X-particle" had a considerably higher mass than m, so Dr. Anderson, who had a natural and profound respect for the constancy of m, was quite sure it was not an electron. Jabez Curry Street of Harvard measured the X-particle's mass at 130 times m, although he said it might be subject to a 25% error either way.

Some weeks ago George Eric MacDonnell Jauncey got a hunch that the X-particle was originally an ordinary electron whose mass had somehow been increased. He imagined what would happen if a high-energy cosmic ray photon struck an electron in the upper atmosphere. Most of the transferred energy would simply give the electron a high-velocity kick. But some of it might be converted into matter which the electron would absorb, increasing its mass. The increase might be any amount at all, depending on the initial energy of the cosmic ray and the variable quantity of matter produced. Dr. Jauncey sent off a letter on these speculations to the editor of the Physical Review.

Then it occurred to him that perhaps the electrons emitted on earth by cathode ray tubes and radioactive substances might be variable in mass, too. If this tremendous hunch were true, some bothersome discrepancies in the behavior of beta rays (fast electrons) shooting out of radium would be cleared up. Also it would make the concept of the neutrino unnecessary. The neutrino is a hypothetical particle imagined by physicists as a carrier of energy which mysteriously disappears when one element is transmuted into another. If it is assumed that the vanished energy has taken the form of greater mass in the electron, the neutrino, which has never been found in the laboratory, loses its reason for existence.

Dr. Jauncey cudgeled his brain for some way to verify experimentally the variable mass of electrons. On December 18 he hit on the idea of passing the electrons from Radium E through a velocity selector, then into a magnetic field. If the particles, selected for uniform velocity, were also of uniform mass, they should be uniformly curved by the field and would strike a photographic film in the same place. By that time the physics department at Washington University was so excited that Jauncey was offered the run of the laboratory and all the help he wanted. He stayed in the laboratory on Christmas Eve instead of going home to his family. One hour before midnight he developed his first film. It showed, as he suspected, that electrons had struck it at different places. The distance between the impacts showed that the mass of some electrons was 2.4 times greater than m.

For two days & nights Jauncey and his helpers worked almost without interruption to make other films. When the A. A. A. S. meeting opened at Indianapolis on December 27, they were ready with their results but it was too late to fit them into the program. Nevertheless news of what Jauncey was doing had leaked out into the scientific world and the physicists were so anxious to hear him that a special conference was arranged. Dr. Charles Thomas Zahn of the University of Michigan, who had been independently working along the same line, was summoned by telegraph, arrived, reported that he was unable to confirm the Jauncey results. Zahn, however, had used a differently arranged apparatus. Nobel Laureate Arthur Holly Compton of the University of Chicago, a onetime colleague of Jauncey's at St. Louis, pored over his experiments, pronounced them competently done but would not commit himself as to their validity. Dr. Compton added somewhat superfluously that they would be of great importance to the whole structure of modern physics if they were confirmed.

Born 50 years ago in Australia, George Eric MacDonnell Jauncey arrived in the U. S. in 1914, studied at Lehigh, joined the Washington University staff in 1920. He likes detective stories and P. G. Wodehouse, is the author of some 75 technical articles and of Modern Physics, a popular college textbook. He realizes quite well the need for further checking of his findings. "I'm out on a limb now," he said philosophically last week. "I hope this thing stands up." He also said that he had got his original hunch while reading TIME'S story on the X-particle in the issue of November 29.

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