AI 中文总结
利用ATLAS探测器在质子-质子碰撞中，通过X→SH→bˉbbˉb寻找新标量粒子，考虑两种事件拓扑，用高斯过程和归一化流分层模型估计背景，搜索特定质量范围，未发现显著过量，设定95%置信水平生产截面乘分支比上限。
AI 中文摘要
进行了一项搜索，寻找一种标量共振X，它衰变成一个标准模型希格斯玻色子H和另一个标量S，每个都衰变成一对底反底夸克对，产生bˉbbˉb的末态。考虑了两种事件拓扑结构，这取决于希格斯玻色子是从单个大半径喷注还是从一对小半径喷注中重建。该分析使用了大型强子对撞机上ATLAS实验在运行2期间收集的质心能量√s = 13 TeV的质子-质子碰撞数据，根据拓扑结构和相关触发条件，积分亮度为126 - 136 fb⁻¹。搜索范围为X的质量300 GeV - 6 TeV和S的质量70 GeV - 5 TeV。利用高斯过程和归一化流的分层模型估计了主要的多喷注和tˉt背景。未观察到超过标准模型背景预期的显著过量。设定了95%置信水平下生产截面乘以分支比的上限，范围从0.7 fb到2.6 pb。
英文摘要
A search is performed for a scalar resonance X decaying into a Standard Model Higgs boson H and an additional scalar S, each decaying into a bottom-antibottom-quark pair, giving a $b\bar{b}b\bar{b}$ final state. Two event topologies are considered, depending on whether the Higgs boson is reconstructed from a single large-radius jet or from a pair of small-radius jets. The analysis uses proton-proton collision data at $\sqrt{s} = 13$ TeV, collected by the ATLAS experiment at the Large Hadron Collider during Run 2, corresponding to an integrated luminosity of 126-136 fb$^{-1}$ depending on the topology and the associated triggers. The search covers masses of 300 GeV-6 TeV for X and 70 GeV-5 TeV for S. The dominant multijet and $t\bar{t}$ backgrounds are estimated with a hierarchical model using Gaussian processes and normalizing flows. No significant excess over the Standard Model background expectation is observed. Upper limits at 95% confidence level are set on the production cross-section times branching ratio, ranging from 0.7 fb to 2.6 pb.
Comments52 pages in total, author list starting page 35, 13 figures, 3 tables, submitted to Phys. Rev. D. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGP-2024-31/index.php
