Charm and beauty production with semi-leptonic decay 
          into electrons in DIS and PHP at ZEUS

                   ZEUS Collaboration

                        Abstract 

The production of heavy quarks in ep interactions has been studied with 
the ZEUS detector at HERA in the photoproduction and DIS regimes using an 
integrated luminosity of 360 pb-1. The heavy flavour events were 
identified using electrons with a transverse momentum of at least 
pT(e)>0.9 GeV in the range eta(e)<1.5. The fractions of events containing 
the heavy quarks were extracted from a likelihood fit using variables 
sensitive to electron identification as well as to semileptonic decays. 
Total and differential cross sections for beauty, and in the case of 
photoproduction also for charm, were measured and compared with 
next-to-leading-order QCD calculations and Monte Carlo models. For squared 
four-momentum exchange of 10<Q^2<1000 GeV^2 the beauty contribution to the 
proton structure function, F2b, was extracted from the double differential 
cross section as a function of x and Q^2.