2025/05/08 by Yang, Meng-Quan, Ru, Peng, Zhang, Ben-Wei
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2505.04906
Nuclear modifications to collinear parton distribution functions are conventionally quantified by the ratios r^\textrmAi(x,Q2) = f^\textrmA,protoni(x,Q2) / f^\textrmprotoni(x,Q2) . For a given nucleus A, these ratios generally depend on the parton momentum fraction x , the probing scale Q2 , and the parton species i . Determining these dependencies relies on a global analysis of diverse experimental data. However, in realistic observables, these dependencies are intricately intertwined, making their extraction challenging. In this paper, we propose a novel approach to effectively image the nuclear modification factors r^\textrmAi(x,Q2) at the observable level in proton-nucleus collisions at the Large Hadron Collider. Specifically, through a combined study of Z -boson production, Z +jet production, and Z+c -jet production, we separately enhance signals arising from light-quark, gluon, and heavy-flavor (charm) distributions in nuclei. This enables us to effectively image the r^\textrmAi(x,Q2) for specific parton species. The feasibility of this method is validated through perturbative calculations at next-to-leading order in the strong coupling constant, employing three sets of nuclear PDF parametrizations: EPPS21, nCTEQ15, and TUJU19. Future measurements of these observables are expected to provide more efficient constraints on nuclear PDFs and yield new insights into the detailed partonic structures of nuclei.