Design and performance of the ENUBET monitored neutrino beam

TL;DR

The paper presents the design of the ENUBET monitored neutrino beam, featuring an instrumented decay tunnel for precise neutrino flux measurement, enabling high-accuracy cross-section studies at the GeV scale.

Contribution

It introduces a novel monitored neutrino beam design with a new focusing system and instrumentation for single-particle lepton detection, improving flux control and measurement precision.

Findings

Achieves percent-level precision in neutrino cross-section measurements.

Demonstrates feasibility of a hornless focusing system for neutrino beams.

Provides an end-to-end design compatible with existing detectors.

Abstract

The ENUBET project is aimed at designing and experimentally demonstrating the concept of monitored neutrino beams. These novel beams are enhanced by an instrumented decay tunnel, whose detectors reconstruct large-angle charged leptons produced in the tunnel and give a direct estimate of the neutrino flux at the source. These facilities are thus the ideal tool for high-precision neutrino cross-section measurements at the GeV scale because they offer superior control of beam systematics with respect to existing facilities. In this paper, we present the first end-to-end design of a monitored neutrino beam capable of monitoring lepton production at the single particle level. This goal is achieved by a new focusing system without magnetic horns, a 20 m normal-conducting transfer line for charge and momentum selection, and a 40 m tunnel instrumented with cost-effective particle detectors. Employing such a design, we show that percent precision in cross-section measurements can be achieved at the CERN SPS complex with existing neutrino detectors.