Measurement of charm and beauty production in deep inelastic ep scattering
                   from decays into muons at HERA
                  
                        ZEUS collaboration

		             Abstract

The production of charm and beauty quarks in ep interactions has been measured 
with the ZEUS detector at HERA for squared four-momentum exchange Q^2>20 GeV^2, 
using an integrated luminosity of 126 pb^-1. Charm and beauty quarks were 
identified through their decays into muons. Differential cross sections were 
measured for muon transverse momenta p_T^{mu}>1.5 GeV and pseudorapidities
 -1.6<eta^{mu}<2.3, as a function of p_T^{mu}, eta^{mu}, Q^2 and 
Bjorken x. The charm and beauty contributions to the proton structure function 
F_2 were also extracted. The results agree with previous measurements based 
on independent techniques and are well described by QCD predictions.