Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

Abstract

The production of beauty quarks in $ep$ interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared $Q^{2} > 10 GeV^{2}$, using an integrated luminosity of $363 pb^{-1}$. The beauty events were identified using electrons from semileptonic $b$ decays with a transverse momentum $0.9 < p_{T}^{e} < 8 GeV$ and pseudorapidity $|\eta^{e}| < 1.5$. The fraction of events containing $b$ quarks was extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. Cross sections for beauty production were measured and compared with leading-order plus parton-shower Monte Carlo predictions and with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function $F_{2}$ was extracted from the double-differential cross section as a function of Bjorken-$x$ and $Q^{2}$.