Design and Diagnostics of High-Precision Accelerator Neutrino Beams

Abstract

Neutrino oscillation physics has entered a new precision era, which poses major challenges to the level of control and diagnostics of the neutrino beams. In this paper, we review the design of high-precision beams, their current limitations, and the latest techniques envisaged to overcome such limits. We put emphasis on “monitored neutrino beams” and advanced diagnostics to determine the flux and flavor of the neutrinos produced at the source at the per-cent level. We also discuss ab-initio measurements of the neutrino energy–i.e., measurements performed without relying on the event reconstruction at the ν detector–to remove any flux induced bias in the determination of the cross sections.

Development and optimization of the ENUBET beamline

“…To this purpose ENUBET employs a narrow-band neutrino beam, with secondary particles focused at 8.5 GeV/c and with a ±5-10% momentum bite. A narrow band beam can be exploited for using the Narrow-Band Off-Axis (NBOA) technique [6,7], to directly correlate the neutrino energy to its impact radius at the near detector with a O (10%) precision, and to achieve a full energy-radius separation between kaon and pion neutrinos. Another critical constraint for the ENUBET beam is to keep the rate of events at the instrumented tunnel walls below a critical pile-up threshold: to ensure this, ENUBET relies on the slow resonant extraction of the primary protons.…”

A New Generation of Neutrino Cross Section Experiments: Challenges and Opportunities

“…A quantitative study of the corresponding systematic uncertainty based on data from current facilities is detailed in [4,56,64]. Once more, designing high-precision facilities [65] to decouple σ ν e (E) from ν e (E)σ ν e (E) or, at least, perform a high precision measurement of ν e (E)σ ν e (E) using the same target as the long-baseline experiments (water or liquid argon) would be a remarkable asset.…”

A New Generation of Neutrino Cross Section Experiments: Challenges and Opportunities

“…A quantitative study of the corresponding systematic uncertainty based on data from current facilities is detailed in [4,55,63]. Once more, designing high-precision facilities [64] to decouple σ ν e (E) from ν e (E)σ ν e (E) or, at least, perform a high precision measurement of ν e (E)σ ν e (E) using the same target as the long-baseline experiments (water or liquid argon) would be a remarkable asset.…”