Measurement of D+- and D0 Production in Deep Inelastic Scattering 
                    Using a Lifetime Tag at HERA

	                ZEUS Collaboration

                            Abstract  

The production of D+/- and D0 mesons has been measured with the ZEUS detector 
at HERA using an integrated luminosity of 133.6 pb^-1. The measurements cover 
the kinematic range 5 < Q2 < 1000 GeV2, 0.02 < y < 0.7, 1.5 < pT(D) < 15 GeV and 
|eta(D)|<1.6. Combinatorial background to the D meson signals is reduced 
by using the ZEUS microvertex detector to reconstruct displaced secondary 
vertices. Production cross sections are compared with the predictions of 
next-to-leading-order QCD which is found to describe the data well. 
Measurements are extrapolated to the full kinematic phase space in order 
to obtain the open-charm contribution, F2(ccbar), to the proton structure 
function, F2.