The knowledge of the initial flux, energy and flavor of current neutrino beams is the main limitation for a precise measurement of neutrino cross-sections. The ENUBET ERC project is studying a facility based on a narrow-band neutrino beam capable of constraining the neutrino fluxes normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In ENUBET, the identification of large-angle positrons from [Formula: see text] decays at single particle level can potentially reduce the [Formula: see text] flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the [Formula: see text] cross-section at the GeV scale. This input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation projects. Furthermore, in narrow-band beams, the transverse position of the neutrino interaction at the detector can be exploited to determine a priori with significant precision the neutrino energy spectrum without relying on the final state reconstruction. This contribution will present the advances in the design and simulation of the hadronic beam line. Special emphasis will be given to a static focusing system of secondary mesons that can be coupled to a slow extraction proton scheme. The consequent reduction of particle rates and pile-up effects makes the determination of the [Formula: see text] flux through a direct monitoring of muons after the hadron dump viable, and paves the way to a time-tagged neutrino beam. Time-coincidences among the lepton at the source and the neutrino at the detector would enable an unprecedented purity and the possibility to reconstruct the neutrino kinematics at source on an event-by-event basis. We will also present the performance of positron tagger prototypes tested at CERN beamlines, a full simulation of the positron reconstruction chain and the expected physics reach of ENUBET.

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高精度窄带中微子束：ENUBET 项目

当前中微子束的初始通量、能量和味道的知识是精确测量中微子横截面的主要限制。ENUBET ERC 项目正在研究一种基于窄带中微子束的设施，该设施能够通过监测仪器化衰变隧道中的相关带电轻子来限制中微子通量标准化。在 ENUBET 中，从 [公式：见文本] 中识别大角正电子在单个粒子水平上衰变可以潜在地将 [公式：见文本] 通量不确定性降低到 1% 的水平。这种设置将允许在 GeV 尺度上对 [公式：见文本] 横截面进行前所未有的测量。这种输入将非常有利于减少下一个长基线振荡项目中系统不确定性的预算。此外，在窄带光束中，探测器处中微子相互作用的横向位置可用于先验地确定中微子能谱，而无需依赖最终状态重建。这一贡献将介绍强子束线的设计和模拟方面的进展。将特别强调可以耦合到慢提取质子方案的次级介子静态聚焦系统。随之而来的粒子速率和堆积效应的降低使得通过在强子倾倒后直接监测 μ 子来确定 [公式：见文本] 通量是可行的，并为带时间标记的中微子束铺平了道路。源处的轻子和探测器处的中微子之间的时间重合将实现前所未有的纯度，并有可能在逐个事件的基础上重建源处的中微子运动学。我们还将展示在 CERN 光束线上测试的正电子标记器原型的性能、正电子重建链的完整模拟以及 ENUBET 的预期物理范围。