# Measuring the Weizsäcker-Williams distribution of linearly polarized gluons at an electron-ion collider through dijet azimuthal asymmetries

Dumitru, Adrian (Department of Natural Sciences, Baruch College, CUNY, 17 Lexington Avenue, New York, New York 10010, USA) (The Graduate School and University Center, The City University of New York, 365 Fifth Avenue, New York, New York 10016, USA) ; Skokov, Vladimir (Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA) (RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA) ; Ullrich, Thomas (Brookhaven National Laboratory, Upton, New York 11973, USA) (Yale University, New Haven, Connecticut 06520, USA)

22 January 2019

Abstract: The production of a hard dijet with small transverse momentum imbalance in semi-inclusive DIS probes the conventional and linearly polarized Weizsäcker-Williams (WW) transverse momentum dependent (TMD) gluon distributions. The latter, in particular, gives rise to an azimuthal dependence of the dijet cross section. In this paper we analyze the feasibility of a measurement of these TMDs through dijet production in DIS on a nucleus at an electron-ion collider. We introduce the mcdijet Monte Carlo generator to sample quark-antiquark dijet configurations based on leading-order parton level cross sections with WW gluon distributions that solve the nonlinear small-$x$ QCD evolution equations. These configurations are fragmented to hadrons using PYTHIA, and final-state jets are reconstructed. We report on background studies and on the effect of kinematic cuts introduced to remove beam jet remnants. We estimate that with an integrated luminosity of 20 ${\mathrm{fb}}^{-1}/\mathrm{nucleon}$ one can determine the distribution of linearly polarized gluons with a statistical accuracy of approximately 5%.

Published in: Physical Review C 99 (2019)