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arXiv 1806.07355hep-ex
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用ATLAS探测器在$\sqrt{s} = 13$ TeV的PDMATHAAB碰撞中在$H \rightarrow aa \rightarrow 4b$通道中寻找与矢量玻色子联合产生并衰变为两个自旋零粒子的希格斯玻色子

Search for the Higgs boson produced in association with a vector boson and decaying into two spin-zero particles in the $H \rightarrow aa \rightarrow 4b$ channel in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

ATLAS Collaboration

摘要:

本文研究了希格斯玻色子衰变为一对自旋为零的粒子$H \rightarrow aa$的奇异衰变过程,其中$a$玻色子迅速衰变为$b$夸克或平均固有寿命$cτ_a$达到6 mm,质量在$20-60$ GeV范围内.搜寻是在希格斯玻色子与$W$或$Z$玻色子结合产生的事件中进行的,产生了一个或两个带电轻子(电子或μ子)的签名和$b$夸克衰变的多个喷流。该分析基于2015年和2016年由欧洲核子研究中心大型强子对撞机的ATLAS探测器记录的$\sqrt{s} = 13$ TeV质子-质子碰撞数据集,对应于36.1 fb $^{-1}$的积分光度。没有观察到明显超过标准模型背景预测的事件,并推导出$pp \rightarrow WH$,$ZH$及其组合的生产截面的95%置信水平上限,乘以衰变链$H \rightarrow aa \rightarrow 4b$的分支比。对于迅速衰变的$a$ -玻色子,$WH$和$ZH$的截面与$H \rightarrow aa \rightarrow 4b$的分支比之和的上限在3.0 pb($m_a= 20$ GeV)到1.3 pb($m_a = 60$ GeV)之间,假设$WH$和$ZH$的截面比遵循标准模型的预测。对于具有较长固有寿命的$a$ -玻色子,在$cτ_a \sim 0.4$ mm处,最严格的极限分别为1.8 pb和0.6 pb。

英文摘要:

A search for exotic decays of the Higgs boson into a pair of spin-zero particles, $H \rightarrow aa$, where the $a$-boson decays into $b$-quarks promptly or with a mean proper lifetime $cτ_a$ up to 6 mm and has a mass in the range of $20-60$ GeV, is presented. The search is performed in events where the Higgs boson is produced in association with a $W$ or $Z$ boson, giving rise to a signature of one or two charged leptons (electrons or muons) and multiple jets from $b$-quark decays. The analysis is based on the dataset of proton-proton collisions at $\sqrt{s} = 13$ TeV recorded in 2015 and 2016 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. No significant excess of events above the Standard Model background prediction is observed, and 95% confidence-level upper limits are derived for the production cross-sections for $pp \rightarrow WH$, $ZH$ and their combination, times the branching ratio of the decay chain $H \rightarrow aa \rightarrow 4b$. For $a$-bosons which decay promptly, the upper limit on the combination of cross-sections for $WH$ and $ZH$ times the branching ratio of $H \rightarrow aa \rightarrow 4b$ ranges from 3.0 pb for $m_a= 20$ GeV to 1.3 pb for $m_a = 60$ GeV, assuming that the ratio of $WH$ to $ZH$ cross-sections follows the Standard Model prediction. For $a$-bosons with longer proper lifetimes, the most stringent limits are 1.8 pb and 0.6 pb, respectively, at $cτ_a \sim 0.4$ mm.

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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