Testing CPT with the Neutral-D System

Abstract

We investigate the issue of testing CPT invariance in the neutral-$D$ system, using $D$ events obtained either from fixed-target experiments or from a tau-charm factory. For both types of experiments we show that the expected suppression of mixing in the $D$ system, normally viewed as a disadvantage for CP tests, allows unsuppressed measurement of certain parameters describing CPT violation. Asymmetries are presented that permit the extraction of parameters for direct CPT violation in the $D$ system and for indirect CPT violation in the $K$ system. We also show that experiments on the neutral-$D$ system provide an alternative means for measuring conventional indirect $T$ violation in the kaon system.