Precision calculations for beyond the Standard Model processes at the LHC

在大型强子对撞机中，对超越标准模型（BSM）过程的精确计算对于探索新物理特性以及在没有发现的情况下推导新粒子质量和新模型参数空间的极限至关重要。在有限数量的特定模型中，存在各种大型强子对撞机生产和衰变过程的精确计算，特别是在QCD的次先导阶。对于标准模型的最小超对称扩展（MSSM），它们被编码在公共计算机程序PROSPINO[1,2,11]中。然而，现有的计算有一个严重的缺点：它们是在一个特定的框架中进行的，不容易修改以描述不同BSM场景下的非标准超对称质谱或过程。新物理学自上而下的模型，如约束超对称，在大型强子对撞机的第一阶段受到了严重挑战。因此，为了将精度计算扩展到更广泛的BSM物理场景，人们需要一种更灵活的方法来运行即将到来的LHC。实现这一目标的唯一有效方法是通过自动化工具。这样的工具需要将QCD的次领先阶精度与大对数阈值修正的总和以及与parton淋浴蒙特卡罗程序的匹配结合起来。在过去的十年里，PROSPINO一直是解释在Tevatron和LHC早期阶段进行的超对称搜索的标准工具。项目A的目标是为即将到来的大型强子对撞机时代提供相应的更强大、更灵活的工具。

Precision calculations for beyond the Standard Model (BSM) processes at the LHC are crucial to explore the properties of new physics and, in the absence of a discovery, to derive limits on new particle masses and the parameter space of new models. Precision calculations, in particular at next-to-leading-order in QCD, exist for various LHC production and decay processes in a limited number of specific models. For the minimal supersymmetric extension of the Standard Model (MSSM) they are encoded in the public computer program PROSPINO [1,2,11]. However, the existing calculations have a severe drawback: they have been carried out in a specific framework and cannot easily be modified to describe non-standard supersymmetric mass spectra or processes in different BSM scenarios.Top-down models of new physics, like constrained supersymmetry, have been severely challenged in the first phase of the LHC. One thus needs a more flexible approach for the upcoming LHC run, in order to extend precision calculations to a wider class of BSM physics scenarios. The only efficient way to achieve this is through automated tools. Such tools need to combine next-to-leading order accuracy in QCD for generic BSM processes with a summation of large logarithmic threshold corrections and the matching with parton shower Monte Carlo programs.For the last decade PROSPINO has been the standard tool for interpreting supersymmetry searches at the Tevatron and at the early phase of the LHC. The goal of Project A is to provide the corresponding more powerful and flexible tool for the upcoming LHC era.