Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass

Abstract: The production of beautyand charm quarksin ep interactions has been studied with the ZEUS detector at HERAfor exchanged four-momentumsquared 5 < Q2< 1000 GeV2 using an integrated luminosity of 354 pb−1. The beautyand charm content in events with at least one jet have been extracted using the invariant massof charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q2, Bjorken x, jet trans- verse energy and pseudorapiditywere measured and compared with next-to-leading-order QCD calculations. The beautyand charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q2. The running beauty-quark mass, mb at the scale mb, was determined from a QCD fit at next-to-leading order to HERAdata for the first time and found to be mb(mb) = 4.07 ± 0.14 (fit)− 0.07+ 0.01(mod.)− 0.00+ 0.05( param.)− 0.05+ 0.08(theo.) GeV.