  Pulsars are known for their superb timing precision, although glitches can
interrupt the regular timing behavior when the stars are young. These glitches
are thought to be caused by interactions between normal and superfluid matter
in the crust of the star. However, glitching pulsars such as Vela have been
shown to require a superfluid reservoir that greatly exceeds that available in
the crust. We examine a model in which glitches tap the superfluid in the core.
We test a variety of theoretical superfluid models against the most recent
glitch data and find that only one model can successfully explain up to 45
years of observational data. We develop a new technique for combining radio and
X-ray data to measure pulsar masses, thereby demonstrating how current and
future telescopes can probe fundamental physics such as superfluidity near
nuclear saturation.
