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arXiv 2106.03584hep-ex
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ATLAS $b$-喷注触发器在 Run 2 期间的配置与性能

Configuration and performance of the ATLAS $b$-jet triggers in Run 2

ATLAS Collaboration

AI总结:

本文报告了 ATLAS 实验在 Run 2 期间对 $b$-喷注触发器的软件改进与性能测量,使轻味喷注抑制能力较 Run 1 提升一个数量级,并首次在重离子数据采集中运行专用 $b$-喷注触发器。

摘要:

在大型强子对撞机 Run 2 数据采集期间(2016 至 2018 年),对 ATLAS 用于识别包含 $b$-强子喷注($b$-喷注)的触发器实施了多项改进。这些改进包括重新配置 $b$-喷注触发软件,以改进主顶点寻找,并使其在高堆积(pile-up)条件下运行更加稳定,同时实现了在在线环境中运行离线重建所使用的复杂标记器(taggers)所需的功能。与 Run 1(2011-2012 年)的性能相比,在相同的 $b$-喷注识别效率下,这些改进使轻味喷注抑制能力提高了一个数量级。此外,还测量了触发器中识别 $b$-喷注的效率,以及满足离线 $b$-标记要求的 $b$-喷注通过触发器的条件效率。推导出校正因子,用于校准模拟中的 $b$-标记效率,使其与数据中观测到的效率一致。相关的系统不确定度显著小于以往测量。此外,在重离子数据采集期间首次运行了 $b$-喷注触发器,使用了专门开发的触发器,通过选择几何上重叠的 μ 子和喷注事件来识别半轻子 $b$-强子衰变。

英文摘要:

Several improvements to the ATLAS triggers used to identify jets containing $b$-hadrons ($b$-jets) were implemented for data-taking during Run 2 of the Large Hadron Collider from 2016 to 2018. These changes include reconfiguring the $b$-jet trigger software to improve primary-vertex finding and allow more stable running in conditions with high pile-up, and the implementation of the functionality needed to run sophisticated taggers used by the offline reconstruction in an online environment. These improvements yielded an order of magnitude better light-flavour jet rejection for the same $b$-jet identification efficiency compared to the performance in Run 1 (2011-2012). The efficiency to identify $b$-jets in the trigger, and the conditional efficiency for $b$-jets that satisfy offline $b$-tagging requirements to pass the trigger are also measured. Correction factors are derived to calibrate the $b$-tagging efficiency in simulation to match that observed in data. The associated systematic uncertainties are substantially smaller than in previous measurements. In addition, $b$-jet triggers were operated for the first time during heavy-ion data-taking, using dedicated triggers that were developed to identify semileptonic $b$-hadron decays by selecting events with geometrically overlapping muons and jets.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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