Design and performance of the ENUBET monitored neutrino beam

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.

The ENUBET monitored neutrino beam: moving towards the implementation of a high precision cross section experiment at CERN

“…An event building algorithm cluster energy deposits correlated in space and time within predefined cuts and a Neural Network is employed to discriminate the signal from the background exploiting differences in the energy deposition pattern. Positrons from 𝐾 𝑒3 are reconstructed with an efficiency of 22% and a S/N∼2, whereas muons from 𝐾 𝜇𝜈 are identified with an efficiency of 34% and a S/N∼6 [6]. Fig.…”

“…The narrow momentum bandwidth and the short baseline of ENUBET allow for an a-priori determination of the neutrino energy that is based on its strong correlation with the radial distance of the interaction vertex from the beam axis induced by the 2-body decay kinematics ("narrow band off-axis" technique). By selecting interactions in radial windows, the incoming neutrino energy can be determined with a precision given by the width of the pion peaks ranging from 10 to 25% in the DUNE energy domain [6]. Such a precise determination at source of the neutrino energy allows to mitigate the uncertainties affecting its measurement through the reconstruction of the interaction final state.…”

Future Long-Baseline Neutrino Experiments

“…This potential is currently being explored within the framework of the ESSnuSB+ design study. Specifically, utilizing less than 10% of the current LINAC's power, without requiring any upgrades, can support a monitored neutrino beam based on the ENUBET concept [62,63]. This beam would enable the measurement of neutrino cross-sections at the percent level below 1 GeV.…”