Thursday 23 January 2025
The European Spallation Source neutrino super-beam project, ESSnuSB, is an ambitious endeavor aimed at precisely measuring the CP-violating phase in the leptonic sector of particle physics. The project involves a long-baseline neutrino experiment that will utilize the powerful European Spallation Source proton linear accelerator to create a high-intensity neutrino beam.
The goal of ESSnuSB is to measure the CP-violating phase with unprecedented precision, which would enable the selection of the correct theoretical model explaining the lack of antimatter in the universe. The project’s conceptual design report has been completed and published, outlining the plans for building a parallel experimental facility at ESS without interfering with its main mission.
The experiment will feature a long baseline setup, consisting of a far water Cherenkov detector located 360 kilometers away from the near detector complex. The near detector suite includes a water Cherenkov detector, a super fine-grained scintillator detector, and an emulsion detector. The high-intensity neutrino beam will be created by accelerating protons to 2.5 GeV kinetic energy and interacting them with a target.
One of the key benefits of ESSnuSB is its ability to measure the CP-violating phase at the second oscillation maximum, which provides a larger interference term and makes the measurement more stable against systematic errors. The project’s sensitivity for CP-violation discovery will reach about 12σ for maximal violation, and it will cover more than 70% of the range of true δCP values with a confidence level greater than 5σ.
In addition to its primary goal, ESSnuSB will also investigate the existence of sterile neutrinos using a short-baseline setup. The project’s design includes novel facilities such as a Low Energy nuSTORM ring and a Low Energy Monitored neutrino beam instrumented tunnel. These facilities will enable precise measurements of low-energy neutrino cross sections and provide opportunities for future physics cases.
The ESSnuSB+ project is the next phase of this endeavor, which aims to extend the instrumentation arsenal by adding two new neutrino beam devices and a near-near detector for precise low-energy neutrino cross-section measurements. The project will also explore the existence of sterile neutrinos using atmospheric neutrinos in the far detector.
The ESSnuSB experiment has significant implications for our understanding of the universe, particularly regarding the matter-antimatter asymmetry problem.
Cite this article: “European Spallation Source Neutrino Super-Beam (ESSnuSB) Project: A Precise Measurement of CP-Violating Phase and Sterile Neutrinos”, The Science Archive, 2025.
Neutrinos, Particle Physics, European Spallation Source, Cp-Violating Phase, Leptonic Sector, Long-Baseline Neutrino Experiment, Proton Linear Accelerator, Cherenkov Detector, Sterile Neutrinos, Nustorm Ring.
Reference: George Fanourakis, ESSnuSB Collaboration, “ESSnuSB status” (2025).
