  Two-particle azimuthal correlations have been measured in neutral current
deep $\mbox{inelastic}$ $\textit{ep}$ scattering with virtuality $Q^2 > 5$
GeV$^2$ at a centre-of-mass energy $\sqrt{s}=318$ GeV recorded with the ZEUS
detector at HERA. The correlations of charged particles have been measured in
the range of laboratory pseudorapidity $-1.5 < \eta < 2.0$ and transverse
momentum $0.1 < p_{\textrm{T}}~< 5.0$ GeV and event multiplicities
$N_{\textrm{ch}}$ up to six times larger than the average $\left<
N_{\textrm{ch}} \right>\approx5$. The two-particle correlations have been
measured in terms of the angular observables $c_n\{2\}=\left< \left< \cos{ n
\Delta\varphi} \right> \right>$, where $n$ is between 1 and 4 and
$\Delta\varphi$ is the relative azimuthal angle between the two particles.
Comparisons with available models of deep inelastic scattering, which are tuned
to reproduce inclusive particle production, suggest that the measured
two-particle correlations are dominated by contributions from multijet
production. The correlations observed here do not indicate the kind of
collective behaviour recently observed at the highest RHIC and LHC energies in
high-multiplicity hadronic collisions.
