SHERPA+RECOLA 框架下环诱导过程的极化截面
Polarised cross sections for loop-induced processes with SHERPA+RECOLA
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中文总结 AI 辅助
本文扩展了SHERPA事件生成器以支持环诱导过程的极化计算，首次在LO及LO+部分子簇射级别实现，并研究了极化定义及QCD/QED重求和效应。
中文摘要 AI 辅助
近年来，研究矢量玻色子极化已成为大型强子对撞机（LHC）物理计划的重要组成部分，因为它提供了对电弱对称性破缺机制以及电弱标准模型规范扇区的独立检验。这些测量需要来自部分子簇射蒙特卡洛模拟的极化模板。其精度尚不能满足即将进行的测量的精度要求，导致在实验分析中出现显著的建模不确定性，这些不确定性将在HL-LHC阶段最迟限制LHC的极化灵敏度。极化的环诱导过程迄今为止尚未被纳入大多数部分子簇射事件生成器中，尽管它们对感兴趣的过程有显著贡献。在这项工作中，我们介绍了蒙特卡洛事件生成器SHERPA中极化框架的扩展，以涵盖固定领头阶（LO）以及LO与部分子簇射匹配的极化环诱导过程。除了描述基于RECOLA矩阵元生成器的极化振幅的方法论外，我们还讨论了相关包容性环诱导过程及其伴随喷注过程中的极化效应，其中几个过程是首次被讨论。我们研究了不同极化定义以及QCD和QED重求和效应的影响。
英文摘要
Studying vector boson polarisation has become an integral part of the LHC physics programme in recent years, as it provides an independent test of the electroweak symmetry-breaking mechanism and the gauge sector of the electroweak Standard Model. These measurements require polarised templates from parton-shower Monte Carlo simulations. Their accuracy does not yet meet the precision requirements of upcoming measurements, leading to significant modelling uncertainties in experimental analyses that will constrain the LHC's polarisation sensitivity at latest in the HL-LHC phase. Polarised loop-induced processes have so far not been included in most parton-shower event generators, despite contributing significantly to processes of interest. In this work, we present the extension of the polarisation framework in the Monte Carlo event generator SHERPA to polarised loop-induced processes at fixed LO and LO matched to parton shower. In addition to a description of the methodology based on polarised amplitudes from the RECOLA matrix element generator, we discuss polarisation effects in relevant inclusive, loop-induced processes and their jet-associated counterparts, several of them for the first time. Both the influence of different polarisation definitions and of QCD and QED resummation effects are investigated.
