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arXiv 2410.04465hep-ex
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环形正负电子对撞机(CEPC)中希格斯玻色子到强子末态的衰变分支比测量

Measurements of decay branching fractions of the Higgs boson to hadronic final states at the CEPC

Xiaotian Ma, Zuofei Wu, Jinfei Wu, Yanping Huang, Gang Li, Manqi Ruan, Fábio L. Alves, Shan Jin, Ligang Shao

AI总结:

本文在CEPC实验假设场景下,利用与Z玻色子联合产生(Z衰变为μ子对)的希格斯玻色子样本,通过PFN模型分离衰变通道并结合迁移矩阵法,实现了其到强子末态分支比的高精度测量并分析了不确定度。

摘要:

环形正负电子对撞机(CEPC)是一种旨在使电子和正电子在高能下碰撞的大型粒子加速器。CEPC的主要目标之一是实现对希格斯玻色子性质的高精度测量,这得益于可产生大量希格斯玻色子且污染极低。本文在CEPC实验背景下,假设质心能量为240 GeV、碰撞数据量为5600 fb⁻¹的场景,呈现了希格斯玻色子衰变为$b\bar{b}/c\bar{c}/gg$以及$τ\bar{τ}/WW^*/ZZ^*$(其中W或Z玻色子强子衰变)的分支比测量结果。本研究中,希格斯玻色子与Z玻色子联合产生,Z玻色子衰变为一对μ子($μ^+μ^-$),该过程具有高效率和高分辨率。为同时高精度分离所有衰变通道,研究考虑了粒子流网络(PFN)——一种基于图的机器学习模型。PFN提供的精确分类用于通过迁移矩阵方法测量分支比,该方法可准确修正各衰变通道中的探测器效应。测量得到的分支比统计不确定度在$H→b\bar{b}$末态中为0.55%,在$H→c\bar{c}/gg/τ\bar{τ}/WW^*/ZZ^*$末态中约为1.5%-16%。此外,本文还讨论了分支比测量的主要系统不确定度来源。

英文摘要:

The Circular Electron Positron Collider (CEPC) is a large-scale particle accelerator designed to collide electrons and positrons at high energies. One of the primary goals of the CEPC is to achieve high-precision measurements of the properties of the Higgs boson, facilitated by the large number of Higgs bosons that can be produced with significantly low contamination. The measurements of Higgs boson branching fractions into $b\overline{b} /c\overline{c} /gg$ and $τ\overlineτ /WW^{*} /ZZ^{*} $, where the $W$ or $Z$ bosons decay hadronically, are presented in the context of the CEPC experiment, assuming a scenario with 5600 fb$^{-1}$ of collision data at a center-of-mass energy of 240 GeV. In this study the Higgs bosons are produced in association with a $Z$ boson, with the $Z$ boson decaying into a pair of muons $(μ^{+}μ^{-})$, which have high efficiency and high resolution. In order to separate all decay channels simultaneously with high accuracy, the Particle Flow Network (PFN), a graph-based machine learning model, is considered. The precise classification provided by the PFN is employed in measuring the branching fractions using the migration matrix method, which accurately corrects for detector effects in each decay channel. The statistical uncertainty of the measured branching ratio is estimated to be 0.55% in $H\to b\overline{b}$ final state, and approximately 1.5%-16% in $H\to c\overline{c} /gg/τ\overlineτ/WW^{*} /ZZ^{*} $ final states. In addition, the main sources of systematic uncertainties to the measurement of the branching fractions are discussed.

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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