The world deep underground laboratories

Abstract

This paper is an introduction to a series of coordinated articles of an EPJ Plus Focus Point on underground physics laboratories, written by the directors of the larger ones and by the coordinators of the principal new projects. The paper is largely based on the text of my lecture Perspectives of underground physics, given at the Enrico Fermi Varenna International School, Course CLXXXII (2011), Neutrino physics and astrophysics, reproduced here by permission of the Italian Physical Society. Underground laboratories provide the low radioactive background environment necessary to explore the highest energy scales that cannot be reached with accelerators, by searching for extremely rare phenomena. Experiments range from the direct search of the dark-matter particles that constitute the largest fraction of matter in the Universe, to the exploration of the properties of the neutrinos, the most elusive of the known particles and which might be particle and antiparticle at the same time, to the investigation on why our universe contains only matter and almost no antimatter, and much more.