Speaker
Description
The Parton-Branching method (PB) allows us to determine Transverse Momentum Dependent (TMD) parton densities from very small to large transverse momentum ($k_T$). In the small $k_T$ range, both intrinsic parton motion and soft gluons contribute. Our study highlights the importance of soft gluons below a resolvable scale for integrated and TMD parton densities.
PB TMD parton densities, coupled with NLO calculations in MC@NLO style, are used to predict Drell-Yan transverse momentum spectra across a broad mass range. Using a free parameter, the intrinsic-$k_T$ width is extracted comparing world data to PB-NLO-HERAI+II-2018 set2 TMD based predictions. Unlike other approaches, the width of the intrinsic-$k_T$ distribution is found independent of the mass of the Drell-Yan pair and of the center-of-mass energy $\sqrt{s}$.
