Beyond the God Particle by Leon M. Lederman, Christopher T. Hill Page A

symmetry (i.e. conserved parity) and a few reactions made no sense at all. The second deep idea was the possibility that rules and overriding laws of physics may in fact depend on the nature of the forces that are involved. As a crazy example, suppose the law of conservation of energy was valid for the electromagnetic forces, the strong forces, and the gravity force, but not valid for the weak force. The stock market value of radioactivity would go through the stratosphere! Not to worry—it isn't so.
     Back to the trip north on Friday evening, following the graceful weaving of the Saw Mill River Parkway, paralleling the Hudson River. Suddenly the musings on the Wu report exploded into an idea. Suddenly, I visualized an experiment one could do with the Nevis cyclotron, an experiment so simple that one could carry it out in a few hours. (In those days, experiments, even with three or four collaborators, took months to carry out—now they take decades.)
     My graduate student, Marcel Weinrich, had been working on an experiment involving muons. Muons are produced in the radioactive disintegrations of certain particles (pions) produced in the Nevis cyclotron. They behave, in all measurements, exactly like electrons—except that they are two hundred times as heavy. The issue of why nature created a heavy twin made muons a favorite object for study. Little did we dream of the treasure the muons would reveal! Marcel's set up, with simple modifications, could be used to look for a big effect. I reviewed the way muons were created in the Columbia accelerator. In this I was a sort of expert, having worked with John Tinlot on the design of external pion and muon beams some years ago when I was a brash graduate student, and the Nevis accelerator was brand new.
     In my mind I visualized the entire process: the accelerator, a 4,000 ton magnet with circular pole pieces about twenty feet in diameter, sandwiches a large stainless steel evacuated box, the vacuum chamber. A stream of protons is injected via a tiny tube in the center of the magnet. The protons spiral outward as strong radio-frequency voltages kick them, adding energy on each turn. Near the end of their spiral trip, the particles have an energy of 400 MeV (1 MeV = 1 million electron volts, as though the protons had been kicked by a 400 million volt battery). Near the edge of the chamber, almost at the place where we would run out of magnet, a small rod carrying a piece of graphite waits to be bombarded by the energetic protons. Their 400 million volts is enough energy to create new particles—pions—as they collide with a carbon nucleus in the graphite target.
     In my mind's eye I could see the pions spewing forward from the momentum of the proton's impact. Born between the poles of the powerful cyclotron magnet, they sweep in a gradual arc toward the outside of the accelerator and do their dance of disappearance; muons appear in their place, sharing the original motion of the pions. The rapidly vanishing magnetic field outside the pole pieces helps to sweep the muons through a channel in a ten-foot-thick concrete shield and into the experimental hall where we would be waiting.
     In the experiment that Marcel had been setting up, muons would be slowed down in a three-inch-thick filter and then be brought to rest in one-inch-thick blocks of various elements. The muons would lose their energy via gentle collisions with the atoms in the material and, carrying a negative electric charge, would finally be captured by the positive nuclei. Since we did not want anything to influence the muon's direction of spin, its capture into orbits could be fatal, so we switched to positive muons. What would positively charged muons do? Probably just sit there in the block spinning quietly until their time came to decay. The material of the block would have to be chosen carefully, and carbon seemed appropriate.
     Now came my key thought while