Electron reconstruction in CMS
Electron reconstruction in CMS
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DOI：
10.1140/epjc/s10052-006-0175-5
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发表时间：
2007-03-01
影响因子：
4.4
通讯作者：
Sirois, Y.
中科院分区：
文献类型：
--
作者：
Baffioni, S.;Charlot, C.;Sirois, Y.
描述了结合跟踪和电磁量热信息重建CMS中孤立电子的能量和动量的方法。重点放在横向动量低于50GeV/c的初级电子上。沉积在电磁量热计中的能量是以团簇(超团簇)来测量的，这些团簇收集了沿着跟踪器体积中电子轨迹发射的韧致辐射光子。电子轨迹是由像素探测器中的种子构建的，该种子通过簇驱动的像素命中匹配算法找到，然后使用高斯和过滤器重建硅条跟踪器中的轨迹。使用对韧致辐射发射和跟踪器材料中的电磁簇射模式敏感的可观测数据对电子进行分类。对超星系团进行了依赖于电子类别的能量标度修正，并获得了相关误差的估计。电子能量是由修正的超星系团能量和跟踪器动量测量的加权组合得出的。电子方向是相互作用顶点处重构电子轨迹的方向。描述了用于物理分析的孤立电子候选者的预选。结合跟踪和量热信息，讨论了用于电子识别的类相关可观测量。
The reconstruction of the energy and momentum of isolated electrons in CMS combining tracking and electromagnetic calorimetry information is described. The emphasis is put on primary electrons with transverse momentum below 50 GeV/c. The energy deposited in the electromagnetic calorimeter is measured in clusters of clusters (superclusters) which collect bremsstrahlung photons emitted along the electron trajectory in the tracker volume. The electron tracks are built from seeds in the pixel detector found via a cluster-driven pixel hit matching algorithm, followed by a reconstruction of trajectories in the silicon strip tracker with a Gaussian sum filter. Electrons are classified using observables sensitive to the pattern of bremsstrahlung emission and electromagnetic showering in the tracker material. Energy scale corrections depending on the electron class are applied to the supercluster and estimates of associated errors are obtained. The electron energy is deduced from a weighted combination of the corrected supercluster energy and tracker momentum measurements. The electron direction is that of the reconstructed electron track at interaction vertex. The pre-selection of isolated electron candidates for physics analysis is described. Class-dependent observables combining tracking and calorimetry information are discussed for electron identification.