Mongillo Martina, Abdullahi Asli, Banto Oberhauser Benjamin, Crivelli Paolo, Hostert Matheus, Massaro Daniele, Molina Bueno Laura, Pascoli Silvia
Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zurich, Switzerland.
Theoretical Physics Department, Fermi National Accelerator Laboratory, Batavia, IL 60510 USA.
Eur Phys J C Part Fields. 2023;83(5):391. doi: 10.1140/epjc/s10052-023-11536-5. Epub 2023 May 10.
A vector portal between the Standard Model and the dark sector is a predictive and compelling framework for thermal dark matter. Through co-annihilations, models of inelastic dark matter (iDM) and inelastic Dirac dark matter (i2DM) can reproduce the observed relic density in the MeV to GeV mass range without violating cosmological limits. In these scenarios, the vector mediator behaves like a semi-visible particle, evading traditional bounds on visible or invisible resonances, and uncovering new parameter space to explain the muon anomaly. By means of a more inclusive signal definition at the NA64 experiment, we place new constraints on iDM and i2DM using a missing energy technique. With a recast-based analysis, we contextualize the NA64 exclusion limits in parameter space and estimate the reach of the newly collected and expected future NA64 data. Our results motivate the development of an optimized search program for semi-visible particles, in which fixed-target experiments like NA64 provide a powerful probe in the sub-GeV mass range.
标准模型与暗物质领域之间的矢量门户是热暗物质的一个具有预测性且引人注目的框架。通过共湮灭，非弹性暗物质（iDM）和非弹性狄拉克暗物质（i2DM）模型可以在不违反宇宙学限制的情况下，在兆电子伏特到吉电子伏特质量范围内重现观测到的遗迹密度。在这些情景中，矢量媒介子表现得像一个半可见粒子，避开了对可见或不可见共振的传统限制，并揭示了新的参数空间来解释μ子反常。通过在NA64实验中采用更具包容性的信号定义，我们利用缺失能量技术对iDM和i2DM施加了新的限制。通过基于重新分析的方法，我们将NA64的排除极限置于参数空间中，并估计新收集的以及预期未来NA64数据的探测范围。我们的结果推动了针对半可见粒子的优化搜索计划的发展，其中像NA64这样的固定靶实验在亚吉电子伏特质量范围内提供了强大的探测手段。
