Center-of-mass energy dependence of intrinsic-$k_{\textrm{T}}$ distributions obtained from Drell–Yan production

The internal motion of partons inside hadrons has been studied through its impact on very low transverse momentum spectra of Drell–Yan (DY) pairs created in hadron-hadron collisions. We study DY production at next-to-leading order using the Parton Branching (PB) method which describes the evolution of transverse momentum dependent parton distributions. The main focus is on studying the intrinsic transverse momentum distribution (intrinsic-$k_{\textrm{T}}$) as a function of the center-of-mass energy $\sqrt{s}$. While collinear parton shower Monte Carlo event generators require intrinsic transverse momentum distributions strongly dependent on $\sqrt{s}$, this is not the case for the PB method. We perform a detailed study of the impact of soft parton emissions. We show that by requiring a minimal transverse momentum, $q_0$, of a radiated parton, a dependence of the width of the intrinsic-$k_{\textrm{T}}$ distribution as a function of $\sqrt{s}$ is observed. This dependence becomes stronger with increasing $q_0$.