Speaker
Description
We study the impact of transverse-momentum-dependent (TMD) evolution on the low-(q_T) spectrum of Drell–Yan lepton-pair production at the Large Hadron Collider. We consider the process (pp \to Z/\gamma^* \to \mu^+\mu^- + X) at (\sqrt{s}=13.6) TeV in the (Z)-boson mass region, focusing on the kinematic regime (q_T \ll M_Z), where TMD factorization is applicable.The (q_T) distribution is calculated in impact-parameter space, with the TMD distributions evolved from an initial scale to the hard scale set by the dilepton invariant mass. We compare the evolved prediction with the corresponding unevolved result to quantify the effect of TMD evolution on the low-(q_T) spectrum. We also investigate the sensitivity of the prediction to the treatment of the large-(b_T) region, where nonperturbative transverse-distance effects become relevant. We find that TMD evolution broadens the low-(q_T) distribution, with the largest modification occurring at transverse momenta well below the hard scale and decreasing as (q_T) increases. The predicted spectrum is also sensitive to the treatment of the large-(b_T) region, indicating a nontrivial interplay between perturbative evolution and nonperturbative transverse-distance effects. Our results provide a focused study of the interplay between TMD evolution and large-(b_T) contributions in low-(q_T) Drell–Yan production, relevant for precision phenomenology and the interpretation of TMD observables at the LHC.