[Paper Review] European Strategy for Accelerator-Based Neutrino Physics

S. Bertolucci, Alain Blondel+23 more|arXiv (Cornell University)|Aug 2, 2012

Neutrino Physics Research6 references17 citations

TL;DR

This paper proposes a coordinated European strategy for accelerator-based neutrino physics, advocating for a long-baseline neutrino program centered on CERN's SPS facility. It recommends a two-pronged approach: a conventional neutrino beam (CN2PY) to the Pyhasalmi mine in Finland and a 10 GeV Neutrino Factory for precision CP violation studies, both aiming to resolve key questions in neutrino oscillations and sterile neutrino searches.

ABSTRACT

Massive neutrinos reveal physics beyond the Standard Model, which could have deep consequences for our understanding of the Universe. Their study should therefore receive the highest level of priority in the European Strategy. The discovery and study of leptonic CP violation and precision studies of the transitions between neutrino flavours require high intensity, high precision, long baseline accelerator neutrino experiments. The community of European neutrino physicists involved in oscillation experiments is strong enough to support a major neutrino long baseline project in Europe, and has an ambitious, competitive and coherent vision to propose. Following the 2006 European Strategy for Particle Physics (ESPP) recommendations, two complementary design studies have been carried out: LAGUNA/LBNO, focused on deep underground detector sites, and EUROnu, focused on high intensity neutrino facilities. LAGUNA LBNO recommends, as first step, a conventional neutrino beam CN2PY from a CERN SPS North Area Neutrino Facility (NANF) aimed at the Pyhasalmi mine in Finland. A sterile neutrino search experiment which could also be situated in the CERN north area has been proposed (ICARUS-NESSIE) using a two detector set-up, allowing a definitive answer to the 20 year old question open by the LSND experiment. EUROnu concluded that a 10 GeV Neutrino Factory, aimed at a magnetized neutrino detector situated, also, at a baseline of around 2200 km (+-30%), would constitute the ultimate neutrino facility; it recommends that the next 5 years be devoted to the R&D, preparatory experiments and implementation study, in view of a proposal before the next ESPP update. The coherence and quality of this program calls for the continuation of neutrino beams at CERN after the CNGS, and for a high priority support from CERN and the member states to the experiments and R&D program.

Motivation & Objective

• To establish a high-priority, coordinated European program in accelerator-based neutrino physics to explore physics beyond the Standard Model.
• To address the fundamental questions of leptonic CP violation and neutrino mixing parameters through long-baseline experiments.
• To support the development of next-generation neutrino facilities, including a Neutrino Factory and deep underground detectors.
• To ensure sustained support for neutrino beam operations at CERN beyond the CNGS program.
• To provide a coherent, competitive, and scientifically robust roadmap for the next European Strategy for Particle Physics (ESPP) update.

Proposed method

• Proposes a conventional neutrino beam (CN2PY) from CERN's SPS North Area Neutrino Facility (NANF) directed toward the Pyhasalmi mine in Finland, at a baseline of ~2200 km.
• Recommends a two-detector setup (ICARUS-NESSIE) in the CERN North Area to search for sterile neutrinos, building on LSND anomaly hints.
• Outlines a design study for a 10 GeV Neutrino Factory as the ultimate facility for precision measurements of neutrino oscillations.
• Advocates for a 5-year R&D and preparatory phase to develop technologies and conduct implementation studies for the Neutrino Factory.
• Integrates two complementary design studies: LAGUNA/LBNO (focused on deep underground detectors) and EUROnu (focused on high-intensity neutrino sources).
• Emphasizes the need for coordinated infrastructure and funding from CERN and member states to ensure long-term program sustainability.

Experimental results

Research questions

• RQ1 Can leptonic CP violation be observed in long-baseline neutrino oscillation experiments?
• RQ2 What is the nature of the anomalous LSND signal, and can it be confirmed or ruled out via a dedicated sterile neutrino search?
• RQ3 What are the optimal parameters for a future Neutrino Factory to achieve the highest precision in measuring neutrino mixing parameters?
• RQ4 How can a coherent, large-scale European neutrino program be structured to maximize scientific impact and international competitiveness?
• RQ5 What infrastructure and R&D investments are required to realize a 10 GeV Neutrino Factory by the next ESPP update?

Key findings

• The CN2PY beam from CERN's SPS to the Pyhasalmi mine offers a viable, high-precision long-baseline neutrino experiment with a baseline of approximately 2200 km.
• The ICARUS-NESSIE two-detector setup in the CERN North Area is proposed as a definitive test for the LSND anomaly, capable of resolving the 20-year-old sterile neutrino question.
• A 10 GeV Neutrino Factory is identified as the ultimate facility for precision studies of neutrino oscillations, enabling the highest sensitivity to CP violation.
• The EUROnu study concludes that a 5-year R&D and implementation phase is essential before a formal proposal can be submitted for the next ESPP update.
• The strategy calls for sustained support of neutrino beams at CERN beyond the CNGS program to maintain scientific momentum and infrastructure readiness.
• The combined LAGUNA/LBNO and EUROnu design studies provide a coherent, science-driven roadmap for Europe’s next major neutrino initiative.