¥Using the Fast vertex
requires that the prompt signals of all T0 counters are aligned in time.
¥The current alignment
procedures align the centroid of the wide T0 time distributions with an
accuracy of 100 ps or better.
¥A more accurate
alignment can be made by comparing the vertex distributions obtained with
individual T0 counters.
¥Small differences in
alignment will result in displacement of the vertex difference distributions (zT0 - zSi) from 0.