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In our experiment, the Fermilab accelerator division sends us a beam of protons, the same protons that compose our atoms. And the protons collide against the target and they produce secondary particles, which are called pions. The pions decay into muons. They are the ones that are responsible for producing the muons that we need to form a muon beam. And we can inject it into our storage rings. We start with a beam of polarized muons. It enters our magnet through the inflector, which allows the muons a straight shot into the main magnetic field of our ring. But because they're injected slightly off-center of our circular path, they get kicked by a
series of three kickers that changes the trajectory of the muons so that they end up on a circular path that goes directly around the ring. Then most of the ring is taken up by the electrostatic quadrupoles, which are devices that create an electric field that focuses the muon beam into the center of the storage region. As they enter the storage ring, it takes about 150 nanoseconds for muons to make one revolution of the storage ring. So eventually they're going to make more than 5,000 revolutions in the storage ring before they all die out. The muons go round and round in circles. Eventually those muons will decay, producing a positron, which is a positively charged electron. And that positron will enter our
detectors, where it produces light that we can detect and measure, and then we measure its energy and time of arrival. With this new experiment combined with the other ones, we're now pushing down to a precision level of about 190 parts per billion. So just to get a feel for that, that's the equivalent of, say, you laying out a million dollars on the floor and then us telling you, "Oh, it's a million dollars, give or take 20 cents."
