May 13 – 19, 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

Multiplicity dependence of azimuthal particle correlations as a probe of collectivity in deep inelastic electron-proton collisions at HERA

May 15, 2018, 2:40 PM
Sala Mosaici-1, 3rd Floor (Palazzo del Casinò)

Sala Mosaici-1, 3rd Floor

Palazzo del Casinò

Parallel Talk Collectivity in small systems Collectivity in small systems


Jacobus Onderwaater (Ruprecht Karls Universitaet Heidelberg (DE))


Recent observations at RHIC and the LHC of two- and multi-particle correlations
in high multiplicity relativistic proton-proton and proton-ion collisions and similarity of the results to those observed in central heavy-ion collisions are often interpreted as an evidence for collective particle production in small collision systems. These results motivate a study in even smaller systems, such as produced in relativistic electron-proton collisions.

A measurement is presented of two-particle correlations in collisions of electron beams at 27.5 GeV with beams of protons at 920 GeV, which corresponds to 318 GeV centre-of-mass energy. A sample of events equivalent to the integrated luminosity of 430 pb$^{-1}$ was recorded with the ZEUS experiment in 2003-2007. The correlations are measured for charged hadrons as a function of event multiplicity for the lab pseudorapidity range $-1.5<\eta_{\rm lab}<2$. To probe the possible contribution due to collective effects, the correlations are studied as a function of the particle's pair separation in pseudorapidity and the pair mean transverse momentum. The observed correlations are compared to available Monte Carlo models of deep inelastic electron-proton scattering. Observations based on the analysis of the ZEUS data put a limit on the possible collective effects in high multiplicity electron-proton collisions.

Collaboration ZEUS
Content type Experiment
Centralised submission by Collaboration Presenter name will be specified later

Primary authors

Matthew Wing (University College London) Jacobus Onderwaater (Ruprecht Karls Universitaet Heidelberg (DE))

Presentation materials