A determination of the CPT violation parameter Re(delta) from the semileptonic decay of strangeness-tagged neutral kaons

We have improved by two orders of magnitude the Limit currently available for the CPT violation parameter Re(delta). To this purpose we have analyzed the full sample of neutral-kaon decays to e pi nu recorded in the CPLEAR experiment, where the strangeness of the neutral kaons was tagged at production and decay time. An appropriate function of the measured decay rates, including information from the analysis of pi(+)pi(-) decay channel, gives directly Re(delta). The result Re(delta) = (3.0 +/- 3.3(stat) +/- 0.6(syst)) X 10(-4) is compatible with zero. Values for the parameters Im(delta), Re(x(-)) and Im(x(+)) were also obtained. (C) 1998 Elsevier Science B.V. All rights reserved. Physics Letters B