Dark Matter Searches with LUX-ZEPLIN

使用 LUX-ZEPLIN 搜索暗物质

• 批准号: 2726959
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2726959
• 关键词: Dark; Matter; Searches; LUX; ZEPLIN

The LZ direct dark matter detector utilizes scintillation photons and electroluminescence photons created by electrons released by ionization to detect particle interactions. For the first science result in 2022, LZ relied upon a fast chain of simulations with parametrised response functions fit to calibration data to build the signal and background models used in setting initial limits. However, such simulations cannot handle the tail of distributions needed to be understood for the full planned exposure of 1000 days. A full chain simulation that tracks the emitted light and charge will be necessary to maximize LZ's sensitivity. LZ has such a simulation, completed prior to detector construction for the third mock data challenge, and used such that mock waveform events could be created to go through the entire reconstruction and analysis chain. Oxford played a leading role in this simulation development. Nicholas Fieldhouse's initial work will focus on the full simulation chain making waveforms that look precisely like waveforms recorded in the LZ detector. Improved simulations from electric field modelling code will be required to build ionization signals from first principles that appear as jagged as LZs do, in contrast to the previous LUX detector. Once an improved full chain simulation is in hand, and verified against extended calibration data sets, it can then be used for improving event processing and testing analyses.Nicholas' projects can then explore the use of the full simulation chain in two ways. The first will be improving our ionization signal reconstruction of integer numbers of extracted electrons by using the pulse substructure. This improved reconstruction can help lower the energy threshold, reduce the uncertainty on the measured energy, and hopefully increase discrimination against electronic recoil backgrounds. The second task would be developing new cuts against accidental coincidence events where the ionization signal is linked to the emission of electrons from the electrodes or from electrons trapped on the liquid surface. A large simulation dataset will play a key role in developing these cuts against rare events that have otherwise proved difficult to eliminate in our first science run.Finally, Nicholas will have hardware experience working on R&D studies of electron emission from electrodes as designs for the next generation liquid xenon TPC dark matter experiment. These hardware studies will benefit from the analysis and simulation work done for LZ, and can hopefully provide useful feedback to the LZ analysis too.

LZ直接暗物质探测器利用电离释放的电子产生的闪烁光子和电致发光光子来探测粒子相互作用。对于2022年的第一个科学结果，LZ依赖于一系列快速模拟，其中参数化响应函数适合校准数据，以建立用于设置初始限值的信号和背景模型。然而，这样的模拟不能处理分布的尾部，需要了解1000天的完整计划暴露。一个完整的链模拟，跟踪发射的光和电荷将是必要的，以最大限度地提高LZ的灵敏度。 LZ有这样一个模拟，在第三次模拟数据挑战的探测器构建之前完成，并用于创建模拟波形事件，以通过整个重建和分析链。牛津大学在这一模拟开发中发挥了主导作用。Nicholas Fieldhouse的初步工作将集中在完整的仿真链上，使波形看起来与LZ探测器中记录的波形完全相同。与以前的LUX探测器相比，需要改进电场建模代码的模拟，以根据第一原理建立电离信号，这些信号看起来像LZ一样锯齿状。一旦改进的全链仿真在手，并根据扩展的校准数据集进行验证，它就可以用于改进事件处理和测试分析。Nicholas的项目可以通过两种方式探索全链仿真的使用。第一个将改进我们的电离信号重建的整数个提取的电子通过使用脉冲子结构。这种改进的重建可以帮助降低能量阈值，减少测量能量的不确定性，并有希望增加对电子反冲背景的区分。第二项任务是开发新的切割方法，以防止偶然的巧合事件，其中电离信号与电极或液体表面捕获的电子的发射有关。一个大型的模拟数据集将在开发这些削减对罕见的事件，否则被证明很难消除在我们的第一次科学运行中发挥关键作用。最后，尼古拉斯将有硬件经验的研发研究的电子发射从电极作为设计的下一代液体氙TPC暗物质实验。这些硬件研究将受益于对LZ所做的分析和仿真工作，并有望为LZ分析提供有用的反馈。