Long-Baseline Neutrino Facility

Long-Baseline Neutrino Facility is a major international particle physics project under construction in the United States. It is designed to host the Deep Underground Neutrino Experiment (DUNE), a next-generation neutrino observatory. The facility will generate an intense beam of neutrinos at Fermilab in Illinois and detect them 1,300 kilometers away at the Sanford Underground Research Facility in South Dakota.

Overview

The project is a flagship endeavor of the U.S. Department of Energy's Office of Science and involves a vast global partnership of institutions. Its primary infrastructure includes a new neutrino beamline and upgraded accelerator complex at Fermilab, known as the Proton Improvement Plan-II. The far detector will be situated deep underground at the Sanford Underground Research Facility in the former Homestake Mine, a site with a rich history in physics including the Homestake experiment. This long-baseline configuration is critical for studying neutrino oscillations over a great distance.

Scientific Goals

The central physics program aims to make definitive measurements of neutrino oscillation parameters to determine the ordering of the three neutrino mass states, a key unknown known as the neutrino mass ordering. It will precisely measure the CP-violating phase in the lepton sector, which could help explain the matter-antimatter asymmetry of the universe through leptogenesis. Additional major goals include detecting neutrinos from a core-collapse supernova within our galaxy, searching for proton decay predicted by grand unified theories, and observing atmospheric neutrinos. These measurements have profound implications for the Standard Model and cosmology.

Experimental Design

The facility will produce the world's most intense beam of neutrinos using the Main Injector accelerator at Fermilab. The near detector complex, located at Fermilab, will characterize the initial beam before oscillations occur. The far detector, installed over a mile underground at the Sanford Underground Research Facility, will use advanced liquid-argon time-projection chamber technology. This technology, pioneered by experiments like ICARUS and MicroBooNE, allows for detailed, three-dimensional imaging of neutrino interaction events. The massive scale of the far detector modules provides the enormous target mass required for the rare interaction rates of these elusive particles.

International Collaboration

The project is built and operated by the DUNE collaboration, which consists of over 1,400 scientists and engineers from more than 200 institutions in over 30 countries. Major contributing nations include Brazil, Czech Republic, India, Italy, Switzerland, and the United Kingdom. Key international partners provide critical detector components, data systems, and computing resources. The CERN neutrino platform has been instrumental in prototyping the large-scale liquid-argon detectors, and institutions like the Rutherford Appleton Laboratory and the Istituto Nazionale di Fisica Nucleare are deeply involved in the construction and development efforts.

Timeline and Status

The project was formally approved by the U.S. Department of Energy in 2015. Major construction began with the excavation of the huge underground caverns at the Sanford Underground Research Facility, which started in 2017. The first neutrino beam from the upgraded accelerator complex is anticipated in the late 2020s. The far detector will be built in stages, with the first detector module expected to begin operation coinciding with the start of beam operations. Full scientific data-taking with the complete multi-module far detector is projected for the early 2030s, positioning it as a leading facility in global particle physics for decades.

Category:Particle physics facilities Category:Neutrino experiments Category:Research and development in the United States