This liquid hydrogen bubble chamber photograph is the third observation of the production of a negatively-charged Omega meson. The sketch beside the photograph shows the proper assignments of a particle to each track. The paths of neutral particles, which produce no bubbles in the liquid hydrogen and therefore leaves no tracks, are shown by dashed lines. The presence and properties of the neutral particles are established by the analysis of the tracks of their charged decay products or the application of the laws of conservation of mass and energy, or a combination of both. The incoming K-negative meson from the Alternating Gradient Synchotron collides with an unseen, stationary proton in the liquid hydrogen with the resultant production of a neutral K-meson, and positive K-meson, and the negative Omega-meson. The negative Omega-meson decays, after a lifetime of approximately one ten-billionth of a second, into a neutral Lambda hyperon and a negative K-meson. The Lambda hyperon then decays into a proton (p), and a negative Pi-meson. The photograph was taken in the 80-inch Liquid Hydrogen Bubble Chamber at Brookhaven National Laboratory. For this experiment a beam of about ten 5 Bev/c negative K-mesons entered the chamber every 2.5 seconds. This beam was produced by allowing the circulating proton beam of the Alternating Gradient Synchotron to strike a target and then separating the negative K-mesons from the other particles produced and conducting them to the 80-inch Bubble Chamber by means of a very long, (about 400 ft), array of magnets and electrostatic separators. The observation of the negative Omega-meson, whose existence was predicted by a group of theoretical physicists, is significant in that it may be the keystone to an orderly arrangement of the previously known particles. Photo circa 1964.
