- Published on 21 October 2012
Deep Underground Science Laboratories and Projects Guest Editor: Alessandro Bettini
Physicists have developed a theoretical description of the elementary building blocks of matter and of the basic forces of Nature, called the Standard Model. It is the most comprehensive theory ever developed and has been tested with high precision up to energies of a few hundred times the proton mass. A new collider, the LHC, has started to work at still higher energies, discovering the last missing element of the SM, the so-called Higgs boson. However we know already that this, and any accelerator of the future, will not be sufficient.
The reason is that three of the four basic forces of Nature, namely strong, electromagnetic and weak, seem to become equal at high energies. Unfortunately the energy scale of the unification is extremely high, so high that we will never be able to reach it with an accelerator. Even higher is the Planck scale, the Big Bang energy, at which, presumably, also the fourth force, gravitation, becomes unified. We can exploit an indirect way, because phenomena characterised by a high-energy scale do, in fact, happen naturally even at the lower, every day, energies. However the higher their intrinsic energy scale is, the more rarely they happen.
The deep underground laboratories are dedicated to the search for these natural, but extremely rare nuclear and subnuclear phenomena, requiring a very low radioactive background environment. The background is due to cosmic rays and to decays of radioactive nuclei present, in traces, in all materials. Underground laboratories, shielded from cosmic and radioactive radiations, have been built in Europe, Japan and North America. More are planned in China, India and South America. They differ in size, depth and organisation, but their scientific programmes are similar and complementary. Other disciplines, like geodynamics and biology, can profit from the unique environment of the underground facilities.
The author of the paper of each laboratory or project is the Director of the given Lab or the PI of the given project.
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