Correction of temperature drifts in the timing from beam scintillators and RPCs

We present evidence for significant drifts with ambient temperature of the timing measurements by beam scintillators and barrel RPCs. The average drift of the time of flight measured by the barrel RPCs is ~60 ps/°C. For the observed temperature variations in the 2002 data taking, this drift leads to an additional fluctuation with sigma(t) ~ 200 ps, which is large on the scale set by the intrinsic RPC time resolution of sigma(t)~160 ps. For the best possible time resolution which is essential for π/e separation by time of flight in the large-angle region, such drifts must be taken into account. Pertinent corrections have been developed which normalize the timing responses of detectors to 25°C ambient temperature.