Precision Measurements of the Standard Model: PDFs, Pile-up, and Production of W+jets at 13 TeV with the ATLAS Detector

背景：将使用欧洲核子研究中心大型强子对撞机(LHC)的完整运行2数据集，进行矢量玻色子(W/Z)+喷注产生的精确标准模型测量。这种测量对于改善我们对这些过程的理解和建模很重要(在新的物理搜索的背景下也很重要，V+喷流通常构成重要的背景)。学生将特别负责(至少在第一次)Muon通道中的W+喷注测量，这是目前尚未发现的，因此从一开始就有很大的机会做出领先的贡献。V+JETS过程对质子结构也很敏感，学生将使用所进行的测量(与来自HERA和LHC的其他数据一起)来确定改进的质子部分分布函数(PDF)。此外，学生将在APPLfast项目的背景下，花费一定比例的时间来扩展PDF测定所需的最先进的工具，该项目提供了在PDF测定中包括新的LHC横截面数据的技术，并被世界各地的所有全球PDF Fiters使用。此外，学生将有很大的机会在以后的几年里扩展到其他领域，包括新的物理搜索，或希格斯测量。目的和目标：通过轮班和JetEtMisse小组内的作者资格鉴定任务，为ATLAS探测器的操作做出贡献，旨在改进连环相撞缓解技术。使用完整的2个ATLAS数据集执行分析，并调查这些测量和其他测量对约束质子PDF的影响。为世界范围内用于质子PDF测定的最先进的工具做出贡献。发布结果。研究和方法的新奇之处：测量将是迄今为止最精确的(使用完整的RUN 2数据集)。我们期待新的分析技术被开发出来，这也导致了系统学的改进。将使用新的蒙特卡罗模拟和最先进的计算(包括在提取质子PDF时)。对以前从未测量过的新观测值的定义，旨在优化QCD建模的敏感性，从而为改进MC模拟和为新的物理搜索更精确地确定背景提供宝贵的信息。开发最先进的质子PDF测定软件工具，将在世界范围内使用。可能首次测量罕见的希格斯衰变通道。

Context:Precision Standard Model measurements will be performed, of vector boson (W/Z) + jet production, using the full Run 2 dataset from the Large Hadron Collider (LHC) at CERN. Such measurements are important to improve our understanding and modelling of these processes (important also in the context of new physics searches, where V+jet often constitute significant backgrounds). The student will in particular be responsible (at least in the first instance) for the W+jet measurement in the muon channel, which is currently uncovered, so there is substantial opportunity to make a leading contribution from the start. V+jets processes are also sensitive to proton structure, and the measurements performed will be used by the student (together with other data from HERA and the LHC) to determine improved proton parton distribution functions (PDFs). In addition, the student will spend some proportion of their time extending the state-of-the-art tools required for PDF determinations, in the context of the APPLfast project, which provides the technology to include new LHC cross section data in PDF determinations, and is used by all global PDF fitters world-wide. In addition, there will be significant opportunity for the student to expand into other areas in later years, including new physics searches, or Higgs measurements.Aims and objectives: Contribute to the operation of the ATLAS detector via shifts, and authorship qualification tasks within the JetEtmiss group, aiming to improve pileup mitigation techniques. Perform analysis using the full Run 2 ATLAS dataset, and investigate the impact of those measurements, and others, on constraining proton PDFs. Contribute to state-of-the-art tools, used world-wide for proton PDF determination. Publish results.Novelty of research and methodology:Measurements will be the most precise to date (using the full Run 2 dataset). We expect new analysis techniques to be developed, leading also to improved systematics. New Monte Carlo simulations, and state-of-the-art calculations will be used (including in the extraction of proton PDFs). Definition of new observables, never before measured, aimed at optimising sensitivity to QCD modelling, thus providing invaluable information for improved MC simulations and more precise determinations of backgrounds to new physics searches. Development of state-of-the-art software tools for proton PDF determination which will be used world-wide. Possible first measurements of rare Higgs decay channels.