Harvard Physicists Trap New Cosmic Corpuscle in "Cloud Chamber"; Nameless, It Can Pierce 10 Cm. of Lead Plates

Putting salt on the tail of a cosmic corpuscle which can penetrate 10 centimeters of lead is no mean feat, but Jabez C. Street, assistant professor of Physics, and Edward C. Stevenson, instructor in Physics, have succeeded in doing just that, according to announcements from Jefferson Research Laboratory.

Many and bewildering are the tiny speeks of matter which participate in the phenomena of nuclear physics, and the last few years have seen a frantic scientific big-game hunt which has successively laid low electrons, protons, positrons, photons, neutrons, alpha and gamma particles. After approximately three years of research, physicists Street and Stevenson have definitely decided that yet another particle should be added to the list. They haven't named it yet, feeling that they should become a little better acquainted with their research-child before they give it an identity.

The machine used to trap this elusive iota is known as a cloud chamber. Nothing new, this apparatus has been in use since 1910; it consists of a chamber containing a mixture of liquid and gas and several lead plates, through which the cosmic radiations pass--the gas is cooled, and produces a fog track along the path of ions formed by the charged corpuscles. This track of condensed vapor can be easily seen with the naked eye and also photographed, showing up as a bright streak on the film. Thus electrons, protons and the new particles, although far too infinitesimal to be directly seen by any optical instrument known, are tricked into disclosing their presence to the human observer.

What got observers Street and Stevenson to thinking that a new sort of corpuscle was in the offing was that the behavior of the cosmic ray particles was not at all like the accepted manner of an electron, which characteristically forms high energy photons, which in turn form more electrons to produce the phenomena known as "electron showers." Due to these showers electrons soon lose their energy, and consequently haven't enough "push" to make much progress through lead. These newly-discovered specks, however, pass through ten centimeters of the metal almost undeviated, with little appreciable loss of energy, and producing no showers.

They cannot be protons, since protons of the same curvature in a magnetic field produce a much thicker trail and are stopped completely at the first lead barrier, unlike the new particles, which pass through all. They cannot be neutrons (neutral particles) since they possess the same charge as the electron or the proton, although the mass is somewhere between these two. Therefore, concluded the investigators, they must be something new, and quite different.

Roughly equal numbers of the particles bearing positive and negative charges have been observed, he said, in spite of earlier erroneous press reports that only negative ones exist.

Curiously enough, Neddermeyer and Anderson of the California Institute of Technology have arrived at the same results as Street and Stevenson, working independently but along somewhat parallel lines. Their results are to be published in an early number of the American Physical Review.