Bitenc, U (reprint author), J Stefan Inst, Ljubljana, Slovenia.
A search for mixing in the neutral D meson system has been performed using semileptonic D(0) -> K((*)-) e(+) nu and D(0) -> K((*)-) mu(+) nu decays. Neutral D mesons from D(*+)-> D(0)pi(+)(s) decays are used and the flavor at production is tagged by the charge of the slow pion. The measurement is performed using 492 fb(-1) of data recorded by the Belle detector. From the yield of right-sign and wrong-sign decays arising from nonmixed and mixed events, respectively, we measure the ratio of the time-integrated mixing rate to the unmixed rate to be R(M)=(1.3 +/- 2.2 +/- 2.0) x 10(-4). This corresponds to an upper limit of R(M) < 6.1 x 10(-4) at the 90% C.L.