论文标题
范德梅尔扫描光度测量和梁梁校正
Van der Meer Scan Luminosity Measurement and Beam-Beam Correction
论文作者
论文摘要
校准大型强子对撞机（LHC）的亮度的主要方法是范德梅尔扫描，横梁互相横跨彼此。这种美丽的方法是在1968年发明的。尽管年龄很高，但它仍然是HADRON COLLIDERS的最佳工具。它提供了最低的校准系统学，这通常仍然主导着LHC实验的整体光度不确定性。该方法的各种细节将在本文中讨论。限制质子 - 普罗顿范德梅尔扫描精度的主要因素之一是梁梁电磁相互作用。它改变了碰撞束的形状，并偏向了测得的光度。在运行的头几年中，四个主要的LHC实验没有试图纠正偏见，因为其复杂性。在2012年，提出了一种校正方法，然后随后由所有实验使用。但是，它基于梁梁力的简化线性近似，因此准确性有限。在本文中，提出了一个新的模拟，该模拟考虑了确切的非线性力。根据光束参数，新方法的结果与$ \ sim1 \％$不同。这需要在2012年以后的所有LHC横截面测量值中传播。新模拟将在LHC中在未来的发光度校准中使用。
The main method for calibrating the luminosity at Large Hadron Collider (LHC) is van der Meer scan where the beams are swept transversely across each other. This beautiful method was invented in 1968. Despite the honourable age, it remains the preferable tool at hadron colliders. It delivers the lowest calibration systematics, which still often dominates the overall luminosity uncertainty at LHC experiments. Various details of the method are discussed in the paper. One of the main factors limiting proton-proton van der Meer scan accuracy is the beam-beam electromagnetic interaction. It modifies the shapes of the colliding bunches and biases the measured luminosity. In the first years of operation, four main LHC experiments did not attempt to correct the bias because of its complexity. In 2012 a correction method was proposed and then subsequently used by all experiments. It was based, however, on a simplified linear approximation of the beam-beam force and, therefore, had limited accuracy. In this paper, a new simulation is presented, which takes into account the exact non-linear force. Depending on the beam parameters, the results of the new and old methods differ by $\sim1\%$. This needs to be propagated to all LHC cross-section measurements after 2012. The new simulation is going to be used at LHC in future luminosity calibrations.
