Measurement of beauty photoproduction using dijet events with a muon with ZEUS at HERA 

Beauty photoproduction in dijet events was measured at HERA with the ZEUS
detector using an integrated luminosity of 124 pb-1.
Beauty was identified in dijet events with a muon in the final state by using
the transverse momentum of the muon relative to the closest jet.In addition, 
the long lifetime of the beauty quark was exploited in order to separate the
beauty signal from background, making use of the microvertex detector
to determine the impact parameter of the muon with respect to the
primary vertex. Cross sections for beauty production as a function of the muon 
and the jets variables are compared to QCD predictions and previous 
measurements without the microvertex detector tag. Dijet correlations were 
also measured and are compared to NLO calculations and Monte Carlo models.