Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ ⁺ μ ^- decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10^-4 GeV^-1 level, improves the Z→μ ⁺ μ ^- mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass.

中文翻译：

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使用赝质量方法进行曲率偏差校正

对非常高动量带电粒子（例如来自电弱矢量玻色子衰变的μ子）的动量测量特别容易受到跟踪探测器未对准所引起的与电荷相关的曲率偏差的影响。对准过程中使用的低动量带电粒子对此类探测器的相干位移的灵敏度有限，因此无法将这些未对准完全限制到弱电物理研究所需的精度。因此，需要其他方法来理解和纠正这些影响。本文使用赝质量法研究了在质心能量 √( 处记录的质子-质子碰撞数据中存在的 LHCb 探测器上存在的曲率偏差s)= 2016 年、2017 年和 2018 年期间的 13 TeV。偏差通过以下公式确定Z→μ ⁺ μ ^-以数据采集周期、磁极性和μ子方向定义的间隔衰减。纠正这些偏差（通常在 10 ^-4 GeV ^-1水平）可以改善Z→μ ⁺ μ ^-质量分辨率提高约 18%，并消除了平均二μ子不变质量的运动学依赖性的几种病理趋势。