nNNPDF3.0: evidence for a modified partonic structure in heavy nuclei
nNNPDF3.0: evidence for a modified partonic structure in heavy nuclei
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DOI：
10.1140/epjc/s10052-022-10417-7
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发表时间：
2022-01
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影响因子：
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通讯作者：
Rabah Abdul Khalek;R. Gauld;T. Giani;E. Nocera;T. Rabemananjara;J. Rojo
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文献类型：
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作者：
Rabah Abdul Khalek;R. Gauld;T. Giani;E. Nocera;T. Rabemananjara;J. Rojo
我们提出了一个更新的确定核部分子分布（nPDF）的全球非线性光学QCD分析的硬过程中的固定目标轻子核和质子核与对撞机质子核实验。除了中性和带电电流深非弹性和Drell-Yan核目标的测量，我们认为生产的电弱规范玻色子，孤立的光子，喷流对，并在大型强子对撞机的质子铅碰撞跨中心的质量能量为5.02 TeV（运行I）和8.16 TeV（运行II）的魅力介子提供的信息。第一次在全球nPDF分析中，这些不同的过程的约束都占在核PDF和自由质子PDF基线。nNNPDF3.0确定的广泛数据集，结合其模型独立的参数化，揭示了核诱导的重核部分子结构修改的强有力证据，特别是胶子和海夸克的小xshadowing，以及胶子的大xanti shadowing。作为一个代表性的唯象应用，我们提供了超高能中微子核子截面的预测，在中微子天文台的数据解释相关。我们的研究结果为正在进行的和未来的实验计划提供了关键输入，从受控对撞机环境中的重离子碰撞到高能天体物理过程的研究。
We present an updated determination of nuclear parton distributions (nPDFs) from a global NLO QCD analysis of hard processes in fixed-target lepton-nucleus and proton-nucleus together with collider proton-nucleus experiments. In addition to neutral- and charged-current deep-inelastic and Drell–Yan measurements on nuclear targets, we consider the information provided by the production of electroweak gauge bosons, isolated photons, jet pairs, and charmed mesons in proton-lead collisions at the LHC across centre-of-mass energies of 5.02 TeV (Run I) and 8.16 TeV (Run II). For the first time in a global nPDF analysis, the constraints from these various processes are accounted for both in the nuclear PDFs and in the free-proton PDF baseline. The extensive dataset underlying the nNNPDF3.0 determination, combined with its model-independent parametrisation, reveals strong evidence for nuclear-induced modifications of the partonic structure of heavy nuclei, specifically for the small-xshadowing of gluons and sea quarks, as well as the large-xanti-shadowing of gluons. As a representative phenomenological application, we provide predictions for ultra-high-energy neutrino-nucleon cross-sections, relevant for data interpretation at neutrino observatories. Our results provide key input for ongoing and future experimental programs, from that of heavy-ion collisions in controlled collider environments to the study of high-energy astrophysical processes.