Emulsion data for track multiplicity

The dataset was extracted from the official OPERA data repository. It contains 817 muon neutrino interactions with the lead target where a muon was reconstructed in the final state. This happens in the so-called charged-current interactions of a muon neutrino. For this data sample, the Collaboration performed a dedicated analysis, with a detailed classification of all particles produced at the neutrino interaction on top of the muon. Indeed, in a muon neutrino interaction with the nucleons of the lead target, different hadrons are produced: the so-called shower hadrons and nuclear fragments produced in the break-up and in the evaporation of the target nucleus. The detailed study of the multiplicity of the hadrons produced provides insights on the mechanism of the hadronic shower formation. This data record contains the information of the neutrino interaction vertices including all the emulsion tracks produced in the interactions. The location of the neutrino interaction and the measurement of the trajectories of all the particles produced is the final step of the event analysis, after the identification of the neutrino interaction bricks done with the electronic detector data. The tracks include nuclear fragments moving both forward and backward. The available information includes minimum ionisation tracks produced in the hadronic shower, heavy ionising particles produced in the nuclear break-up and evaporation.

该数据集源于官方OPERA数据仓库。其中收录了817次μ子中微子与铅靶的相互作用事件，这些事件中在最终态成功重建了μ子。这一现象发生在中微子μ子与铅靶核子之间的所谓带电流相互作用中。对于此数据样本，合作团队执行了专项分析，对中微子相互作用过程中产生的所有粒子进行了细致的分类。实际上，在μ子中微子与铅靶核子的相互作用中，会产生多种强子：所谓的 shower 强子和在靶核分裂及蒸发过程中产生的核碎片。对产生强子的多重性的详细研究，有助于揭示强子 shower 形成机制。该数据记录包含了中微子相互作用顶点的信息，以及相互作用中产生的所有乳胶轨迹。中微子相互作用的定位以及对所有产生粒子轨迹的测量是事件分析的最后一步，此步骤在利用电子探测器数据识别中微子相互作用砖块之后完成。轨迹包括向前和向后移动的核碎片。可用的信息包括在强子 shower 中产生的最小电离轨迹，以及在与核分裂及蒸发相关的重电离粒子。