论文标题

在CMS中最高夸克的蒙特卡洛样品中的参数重新加权的机器学习方法

Machine learning approaches for parameter reweighting in Monte-Carlo samples of top quark production in CMS

论文作者

Guglielmi, Valentina

论文摘要

在高能粒子物理学中,需要复杂的蒙特卡洛(MC)模拟来将理论预测与可测量的数量进行比较。需要生成许多和大的MC样品,以考虑所有系统学。因此,MC统计数据(因此MC建模不确定性)成为大多数测量值的限制因素。此外,这些程序的重大计算成本在大多数物理分析中成为瓶颈。因此,找到一种减少生成的MC样本以减少MC统计不确定性并降低计算成本的方法非常重要。在这些程序中,我们使用调整和重新加权的分类(DCTR)评估了一种称为深神经网络的方法。 DCTR是一种基于深层神经网络(DNN)的方法,可利用事件中的完整运动信息将模型或模型参数和拟合模拟的不同模型或拟合模拟。这种重新加权方法避免了需要通过将相关变化纳入单个样本中多次模拟检测器响应。通过这种方式,MC统计不确定性和计算成本都降低了。此外,与标准重新加权不同,在该标准重新加权上,在真实层面上进行了两个直方图的垃圾箱比例,多维信息和无键信息可以用作DNN的输入。此外,DCTR可以执行其他当前现有方法不可能执行的任务,例如连续重新加权作为任何MC参数的函数,同时重新重量对更多MC参数进行重新重量,并将MC模拟调整为数据。我们在顶级夸克对生产的MC模拟上测试了方法,我们将其重新为不同的SM参数值和不同的QCD模型。

In high-energy particle physics, complex Monte Carlo (MC) simulations are needed to compare theory predictions to measurable quantities. Many and large MC samples are needed to be generated to take into account all the systematics. Therefore, the MC statistics (and hence the MC modeling uncertainties) become a limiting factor for most measurements. Moreover, the significant computational cost of these programs becomes a bottleneck in most physics analyses. Therefore, it is extremely important to find a way to reduce the MC samples generated to decrease the MC statistical uncertainties and lower the computational cost. In these proceedings, we evaluate an approach called Deep neural network using Classification for Tuning and Reweighting (DCTR). DCTR is a method based on a Deep Neural Network (DNN) to reweight simulations to different models or model parameters and fit simulations, using the full kinematic information in the event. This reweighting methodology avoids the need for simulating the detector response multiple times by incorporating the relevant variations in a single sample. In this way, the MC statistical uncertainties and the computational cost are both reduced. Moreover, unlike the standard reweighting, in which the ratio in bins of two histograms at truth level is performed, multidimensional and unbinned information can be used as inputs to the DNN. In addition, DCTR can perform tasks that are not possible with other current existing methods, such as continuous reweighting as a function of any MC parameter, simultaneous reweighting of more MC parameters and tuning MC simulations to the data. We test the method on MC simulations of top quark pair production, which we reweight to different SM parameter values and to different QCD models.

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