  We experimentally investigate the response of a sheared granular medium in a
Couette geometry. The apparatus exhibits the expected stick-slip motion and we
probe it in the very intermittent regime resulting from low driving.
Statistical analysis of the dynamic fluctuations reveals notable regularities.
We observe a possible stability property for the torque distribution,
reminiscent of the stability of Gaussian independent variables. In this case,
however, the variables are correlated and the distribution is skewed. Moreover,
the whole dynamical intermittent regime can be described with a simple
stochastic model, finding good quantitative agreement with the experimental
data. Interestingly, a similar model has been previously introduced in the
study of magnetic domain wall motion, a source of Barkhausen noise. Our study
suggests interesting connections between different complex phenomena and
reveals some unexpected features that remain to be explained.
