AI 中文总结
本研究利用J-PARC $ν_μ$束流与NINJA乳胶探测器，测量水的带电电流相互作用末态运动学，为后续大样本NINJA数据分析建立了框架。
AI 中文摘要
我们利用暴露于J-PARC $ν_μ$聚焦束流的NINJA核乳胶探测器，记录了水的带电电流 inclusive $ν_μ$相互作用的通量积分样本，对其中的带电粒子多重数以及μ子、质子和带电π介子的运动学分布开展研究。该数据对应靶质子注量为$4.63×10^{20}$个，中微子能谱峰值位于0.7 GeV。本分析从质量为3.9 kg的水基准体积中选取了82个事例，对应运行期间暴露的总水靶质量的5%。将重建的分布与基于T2K实验所用相互作用模型的蒙特卡罗预测进行比较，观测到的分布在估计的不确定度范围内与预测总体一致，不过质子角分布与预测存在一定张力。当前结果受统计不确定度限制。本分析是首次利用核乳胶数据，在水靶上借助$ν_μ$聚焦束流开展对低至200 MeV/$c$质子动量敏感的质子运动学研究，并为未来使用大得多的NINJA数据样本的测量建立了分析框架。
英文摘要
We present a study of charged-particle multiplicities and the kinematic distributions of muons, protons, and charged pions in a flux-integrated sample of charged-current inclusive $ν_μ$ interactions on water recorded with the NINJA nuclear emulsion detector exposed to the J-PARC $ν_μ$-focused beam. The data correspond to an exposure of $4.63\times10^{20}$ protons on target, with a neutrino energy spectrum peaked at 0.7 GeV. In this analysis, 82 events are selected from a fiducial water volume with a mass of 3.9 kg, corresponding to 5% of the total water target mass exposed during the run. The reconstructed distributions are compared with Monte Carlo predictions based on the interaction model used in the T2K experiment. The observed distributions are generally consistent with the predictions within the estimated uncertainties, although the proton angular distribution exhibits some tension with the prediction. The results are currently limited by statistical uncertainties. This analysis provides the first study of proton kinematics with sensitivity to proton momenta as low as 200 MeV/$c$ with a $ν_μ$-focused beam on a water target using nuclear emulsion data and establishes the analysis framework for future measurements with substantially larger NINJA data samples.
Comments39 pages, 22 figures
