An overview on the longitudinal Stern-Gerlach effect

The TE rf cavity system is undoubtedly very appealing since it gives the possibility of polarizing both proton and antiproton beams at the end of their acceleration cycles. Practically, this process is similar to the e{+-} self-polarization induced by synchrotron radiation. Should this method prove unsuccessful, the small polarizer ring can still be used for attaining polarized antiprotons. In fact, the rf requirements for the low energy ring are less demanding than for high energy colliders: a saw-tooth wave-form can be implemented, and the spin separation can be undergone by successive bursts of quasi-monoenergetic antiprotons. Stochastic cooling techniques, such as momentum to frequency pick-ups, can be directly useful for both methods, either in the very first tests or in the final operating modes. These techniques could also be employed in order to carry out experiments of elementary particles physics, even in presence of filamentation phenomena. In fact, the two bunches of particles with opposite spin states have a core whose particles will always undergo synchrotron oscillations with small amplitude, i.e. will never be entangled by filamentation. Therefore, these innermost particles could be time-tagged and used in either collider or fixed target experiments. Besides, when the bunch cores become empty, a rf reshuffling could pour other particles into them and this process can be iterated