Multijet production at low $x_{\mathrm{Bj}}$ in deep inelastic scattering at HERA

Abstract

Inclusive dijet and trijet production in deep inelastic $ep$ scattering has been measured for $10<Q^2<100$ GeV${}^2$ and low Bjorken $x$, $10^{-4}<x_{\mathrm{Bj}}<10^{-2}$. The data were taken at the HERA $ep$ collider with centre-of-mass energy $\sqrt{s} = 318 \gev$ using the ZEUS detector and correspond to an integrated luminosity of $82{\mathrm{pb}}^{-1}$. Jets were identified in the hadronic centre-of-mass (HCM) frame using the $k_T$ cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of $Q^2$, $x_{\mathrm{Bj}}$, jet transverse energy, and jet pseudorapidity. As a further examination of low-$x_{\mathrm{Bj}}$ dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at $\mathcal{O}(\hat{I}{\pm }_s^3)$ generally describe the trijet data well and improve the description of the dijet data compared to the calculation at $\mathcal{O}(\hat{I}{\pm }_s^2)$.

27 pages, 12 figures, 5 tables, submitted to Nucl. Phys. B