论文标题
建模$ W^+ W^ - $生产LHC的速度差距很快
Modelling $W^+ W^-$ production with rapidity gaps at the LHC
论文作者
论文摘要
储层计算是预测湍流的有力工具，其简单的架构具有处理大型系统的计算效率。然而，其实现通常需要完整的状态向量测量和系统非线性知识。我们使用非线性投影函数将系统测量扩展到高维空间，然后将其输入到储层中以获得预测。我们展示了这种储层计算网络在时空混沌系统上的应用，该系统模拟了湍流的若干特征。我们表明，使用径向基函数作为非线性投影器，即使只有部分观测并且不知道控制方程，也能稳健地捕捉复杂的系统非线性。最后，我们表明，当测量稀疏、不完整且带有噪声，甚至控制方程变得不准确时，我们的网络仍然可以产生相当准确的预测，从而为实际湍流系统的无模型预测铺平了道路。
We present a new calculation of $W^+ W^-$ production in the semi-exclusive channel, that is either with intact outgoing protons or rapidity gaps present in the final state, and with no colour flow between the colliding protons. This study provides the first complete prediction of the $W^+ W^-$ semi-exclusive cross section, as well as the breakdown between elastic and proton dissociative channels. It combines the structure function calculation for a precise modelling of the region of low momentum transfers with a parton-level calculation in the region of high momentum transfers. The survival factor probability of no additional proton-proton interactions is fully accounted for, including its kinematic and process dependence. We analyse in detail the role that the pure photon-initiated ($γγ\to W^+ W^-$) subprocess plays, a comparison that is only viable by working in the electroweak axial gauge. In this way, we find that the dominance of this is not complete in the proton dissociative cases, although once $Z$-initiated production is included a significantly better matching to the complete calculation is achieved. A direct consequence of this is that the relative elastic, single and double dissociative fractions are in general different in comparison to the case of lepton pair production. We present a direct comparison to the recent ATLAS data on semi-exclusive $W^+ W^-$ production, finding excellent agreement within uncertainties. Our calculation is provided in the publicly available SuperChic 4.1 Monte Carlo (MC) generator, and can be passed to a general purpose MC for showering and hadronization of the final state.
