Beauchesne Hugues, Cazzaniga Cesare, de Cosa Annapaola, Doglioni Caterina, Fitschen Tobias, di Cortona Giovanni Grilli, Zhou Ziyuan
Physics Division, National Center for Theoretical Sciences, Taipei, 10617 Taiwan.
ETH Zürich, Institute for Particle Physics and Astrophysics, 8093 Zurich, Switzerland.
Eur Phys J C Part Fields. 2023;83(7):599. doi: 10.1140/epjc/s10052-023-11775-6. Epub 2023 Jul 11.
This Letter proposes a new signature for confining dark sectors at the Large Hadron Collider. Under the assumption of a QCD-like hidden sector, hadronic jets containing stable dark bound states could manifest in proton-proton collisions. We present a simplified model with a boson yielding the production of jets made up of dark bound states and subsequently leading to the decays of those that are unstable to leptons and Standard Model quarks. The resulting signature is characterised by non-isolated lepton pairs inside semi-visible jets. We estimate the constraints on our model from existing CMS and ATLAS analyses. We propose a set of variables that leverage the leptonic content of the jet and exploit them in a supervised jet tagger to enhance the signal-to-background separation. Furthermore, we discuss the performance and limitations of current triggers for accessing sub-TeV masses, as well as possible strategies that can be adopted by experiments to access such low mass regions. We estimate that with the currently available triggers, a high mass search can claim a discovery (exclusion) of the boson with a mass up to 4.5 TeV (5.5 TeV) with the full Run 2 data of the LHC when the fraction of unstable dark hadrons decaying to lepton pairs is around , and with a coupling of the to right-handed up-type quarks of 0.25. Furthermore, we show that, with new trigger strategies for Run 3, it may be possible to access masses down to 700 GeV, for which the event topology is still composed of two resolved semi-visible jets.
本信函提出了一种在大型强子对撞机中限制暗区的新信号特征。在类量子色动力学隐藏区的假设下，包含稳定暗束缚态的强子喷注可能在质子 - 质子碰撞中显现。我们给出了一个简化模型，其中一个玻色子产生由暗束缚态构成的喷注，并随后导致那些对轻子和标准模型夸克不稳定的暗束缚态发生衰变。由此产生的信号特征是半可见喷注内的非孤立轻子对。我们根据现有的CMS和ATLAS分析估计了对我们模型的限制。我们提出了一组利用喷注的轻子成分的变量，并在一个有监督的喷注标记器中利用它们来增强信号与背景的分离。此外，我们讨论了当前用于探测低于 TeV 质量的触发机制的性能和局限性，以及实验可以采用的探测此类低质量区域的可能策略。我们估计，在目前可用的触发机制下，当不稳定暗强子衰变为轻子对的比例约为 ，且该玻色子与右手型上夸克的耦合为 0.2时，利用大型强子对撞机完整的运行2数据进行高质量搜索，可以宣称发现（排除）质量高达 4.5 TeV（5.5 TeV）的该玻色子。此外，我们表明，对于运行3采用新的触发策略，有可能探测到低至700 GeV的质量，此时事件拓扑结构仍由两个分辨的半可见喷注组成。
