Sterile neutrino search at the Fermilab Short Baseline Neutrino Program

作为短基线中微子（SBN）计划的一部分，短基线近探测器（SBND）将是沿费米实验室助推中微子束（BNB）轴线放置的三个液态氩时间投影室（LArTPC）中微子探测器之一。该探测器目前处于建设阶段，预计将于2022年下半年开始运行。SBND的特点是出色的成像能力，每年将记录超过一百万个中微子相互作用。由于其独特的测量分辨率和统计数据的结合，SBND将执行一个丰富的中微子相互作用测量计划和超越标准模型（BSM）的新物理搜索。它将通过执行非振荡事件率的精确特征，以及通过限制BNB通量和中微子-氩气横截面系统不确定性，实现整个SBN无菌中微子计划的潜力。该项目的目标是在VALOR分析框架内，对记录在snd上的几个关键的独占最终状态样本进行联合分析。这项工作的目的是i)改善SBN使用的GENIE模拟中中微子相互作用的现象学，ii)产生严格的SBN驱动的通量和横截面系统不确定性约束，以及iii)改进对ICARUS的非振荡事件率的估计，ICARUS是SBN计划的远探测器。该项目的目的是使整个SBN计划的振荡灵敏度，以确定5a排除LSND/MiniBooNE异常所建议的参数的光无菌中微子假设，依赖于将snd和ICARUS之间不相关的所有系统分类约束在1%水平的能力。该项目的另一个平行目标是促进SBND独家最终状态选择的发展，特别强调单介子的产生。

The Short-Baseline Near Detector (SBND) will be one of three liquid Argon Time Projection Chamber (LArTPC) neutrino detectors positioned along the axis of the Booster Neutrino Beam (BNB) at Fermilab, as part of the Short-Baseline Neutrino (SBN) Program. The detector is currently in the construction phase and is anticipated to begin operation in the second half of 2022. SBND is characterised by superb imaging capabilities and will record over a million neutrino interactions per year. Thanks to its unique combination of measurement resolution and statistics, SBND will carry out a rich program of neutrino interaction measurements and novel searches for physics beyond the Standard Model (BSM). It will enable the potential of the overall SBN sterile neutrino program by performing a precise characterisation of the unoscillated event rate, and by constraining BNB flux and neutrino-Argon cross-section systematic uncertainties. The goal of this project is to perform, within the VALOR analysis framework, a joint analysis of several key exclusive final state samples recorded on SBND. The purpose of this effort is to i) improve the phenomenology of neutrino interactions in the GENIE simulation used by SBN, ii) produce stringent SBND-driven constraints of flux and cross-section systematic uncertainties, and iii) improve the estimates of the unoscillated event rates at ICARUS, the far detector of the SBN program. The aim of this project is to enable the oscillation sensitivity of the full SBN program that, for the definitive 5a exclusion the hypothesis of light sterile neutrinos with the parameters suggested by the LSND/MiniBooNE anomaly, rests upon the ability to constrain at 1% level all the systematics that are uncorrelated between SBND and ICARUS. A parallel objective of this project is to contribute to the development of exclusive final state selections on SBND, with particular emphasis on single-pion production.