A proposed underground laboratory would be an important step in addressing three science questions of “paramount importance”, says a report released today by the National Academies.
The report evaluated the physics experiments that could be performed at the Deep Underground Science and Engineering Laboratory (DUSEL), a cavernous space physicists want dug out nearly 1,500 metres below ground in the abandoned Homestake mine near Lead, South Dakota (pictured).
The report, led by Andrew Lankford of the University of California at Irvine, found that three physics experiments would be particularly worthwhile in this quiet space, sheltered from the noisy cosmic ray particles that rain down on the Earth’s surface:
1) Dark matter. A giant detector on the order of a ton or more, filled with water or liquid argon, could detect and characterize dark matter, the elusive stuff that makes up 80% of the matter in the Universe.
2) Neutrino oscillation. This experiment would begin with a beam of neutrinos shot from Fermi National Accelerator Laboratory, 1,300 kilometres away in Batavia, Illinois. A detector at DUSEL would look for ways in which the neutrinos morphed from one flavour to another en route, and, in doing so, the experiment would shed light on the way that the Universe favours matter over antimatter.
3) Neutrino-less double-beta decay. This experiment would look for a rare particle decay that could measure the mass of the neutrino in absolute terms, rather than in the relative terms governed by flavour oscillation.
The report noted that an underground lab would also be useful for two less crucial, but still worthwhile physics experiments: setting stricter limits on the decay of the proton, and detecting neutrinos from a supernova, should one go off in the galaxy during the lifetime of the experiment. Moreover, the report notes, a lab like DUSEL would provide a home for valuable experiments in subsurface engineering, the geosciences, and the biosciences.
But the report’s glowing reviews of the science may all be moot. That’s because, in December, the National Science Foundation pulled out of the project, after its governing board balked at the price. That left the Energy Department wondering if it could afford to finance the facility on its own.
Last month, advisers to the Energy Department reviewed a report that looked at the cost of doing just that. The cheapest way of doing all three physics experiments at Homestake would still cost between $1.6 billion and $2.1 billion, according to that report, led by Jay Marx of the California Institute of Technology in Pasadena.