LBNO

LBNO
Name	LBNO
Full name	Long Baseline Neutrino Observatory
Type	Proposed particle physics experiment
Focus	Neutrino oscillation physics, mass hierarchy, CP violation
Status	Cancelled / Pre-project proposals
Countries	France, United Kingdom, Czech Republic, Poland, Switzerland, Russia, others
Institutions	CERN, INFN, STFC, CNRS, IHEP, JINR

LBNO

LBNO was a proposed long-baseline neutrino project intended to probe fundamental properties of neutrinos and to connect major European laboratory infrastructures with deep underground detector sites. The proposal sought to exploit accelerator facilities and large-scale detection technologies to address the neutrino mass ordering and leptonic CP violation, linking research programs at CERN, regional research agencies such as STFC and CNRS, and underground laboratories like Gran Sasso and proposed mines in Pyhäsalmi.

Overview

LBNO aimed to create a high-intensity neutrino beam from an accelerator complex and measure oscillated neutrinos at a distant underground detector to determine mass hierarchy and search for CP-violating effects. The concept built on precedents including T2K, NOvA, and MINOS while connecting to next-generation plans such as DUNE and Hyper-Kamiokande. LBNO proposals explored deep-underground siting analogous to SNOLAB and Laboratoire Souterrain de Modane to reduce cosmic backgrounds for searches comparable to those in Super-Kamiokande and SNO.

Scientific Objectives

Primary objectives included determination of the neutrino mass ordering (normal vs inverted) and precision measurement of the CP phase in the Pontecorvo–Maki–Nakagawa–Sakata matrix used for neutrino mixing, complementing goals of IceCube and KATRIN. The program also intended to measure oscillation parameters such as Δm^2_32 and θ_23 with precision comparable to results from KamLAND and RENO, and to search for sterile neutrinos motivated by anomalies seen in LSND and MiniBooNE. Additional physics targets included studies of supernova neutrino bursts relevant to Supernova 1987A analyses, proton decay channels predicted by grand unified theories tested in Proton decay searches, and neutrino interaction cross sections relevant to MINERvA and T2K ND280.

Experimental Design and Detector Technology

LBNO designs emphasized a far detector using large-mass technologies such as liquid argon time projection chambers (LArTPC) similar to those developed for ICARUS and later scaled for DUNE, and magnetized iron calorimeters reminiscent of MINOS designs. Near detector systems were planned to monitor the unoscillated beam with instrumentation concepts influenced by NA61/SHINE and HARP hadron-production experiments. Beamline proposals drew on accelerator expertise at CERN SPS and concepts tested in PS and SPS upgrades. Detector readout and cryogenics leveraged developments from FNAL programs and industrial partners experienced with large cryostats as in ATLAS and CMS infrastructure projects. Background mitigation strategies adopted deep-underground siting comparable to Gran Sasso and active veto systems like those used in Borexino.

Site and Baseline Considerations

LBNO proposed baselines on the order of several hundred to over a thousand kilometers to maximize matter effects for hierarchy determination, with candidate routes evaluated between accelerator complexes and deep mines such as Pyhäsalmi in Finland and underground facilities associated with Boulby and Modane. The choice of baseline balanced sensitivity to CP violation and mass ordering against geological access, infrastructure, and international logistics considerations analogous to deliberations for LBNE and DUNE site selection. Geotechnical surveys, seismic profiling, and mine shaft logistics were planned following practices used in projects at Sudbury and Baksan.

Collaboration and Project History

The LBNO initiative grew from European neutrino community planning exercises and roadmap processes led by organizations including CERN and national funding agencies such as STFC and CNRS. Scientific steering groups involved collaborations among institutes like IN2P3, INFN, CEA, and universities across United Kingdom, France, Poland, Czech Republic, and Switzerland. The proposal interacted with global efforts such as the European Strategy for Particle Physics and influenced subsequent proposals that fed into international projects like DUNE. Key figures and working groups from existing experiments such as ICARUS, OPERA, and T2K contributed technical expertise and cross-disciplinary personnel transitions.

Funding, Timeline, and Status

LBNO advanced through conceptual design and community review phases and sought funding from national agencies including STFC, INFN, and EU framework programs, but did not secure the full construction commitments required to reach realization. Following reviews and strategy updates, resources and scientific priorities shifted toward alternative large-scale projects such as DUNE and Hyper-Kamiokande, and LBNO in its original form was not pursued to completion. Elements of LBNO's technology studies and site investigations influenced later funded efforts through knowledge transfer to collaborations associated with CERN neutrino platform activities and regional underground laboratory developments like Pyhäsalmi Mine projects.

Category:Neutrino experiments