  We observed the low-mass X-ray binary Sco X-1 for 12 nights simultaneously
using the Rossi X-Ray Timing Explorer and the Otto Struve Telescope at McDonald
Observatory at 1 second time resolution. This is among the most comprehensive
simultaneous X-Ray/optical data sets of Sco X-1. Evidence of reprocessing was
observed in the form of nine positive, near-zero lag peaks in the cross
correlation function, eight of which were relatively small and took the shape
of piecewise exponential functions. These peaks were initially identified by
eye, after which a computational identification scheme was developed to confirm
their significance. Based on their short lags (less than 4 seconds), as well as
their occurrence on the flaring branch and soft apex, the small cross
correlation features are likely to be caused by reprocessing off the outer
disc, although the companion could still make a contribution to their tails.
The Z track was parameterized using a rank number scheme so that the system's
location on the track could be numerically defined. Plotting the results
against the optical reveals an increasing step function when moving from the
horizontal to the normal to the flaring branch, with differential optical
levels at ~0.47, ~0.57, and ~1.1 respectively. An additional correlation
between Z track location and the optical was found on the upper flaring branch.
An optical intensity histogram reveals a transition region between the normal
and flaring branches with only intermediate fluxes.
