The law of conservation of energy is one of the pillars of modern physics. However, some experiments in the 30s seemed to indicate that the energy was not conserved. The evidence was so strong that scientist such as Niels Bohr were considering that maybe in some circumstances the energy could not be conserved.
To solve this issue, Wolfgang Pauli postulated the existence of a new and elusive particle which would explain the missing energy.
In 1956, a revolutionnary experiment from Cowan and Reines showed this particle did indeed exist: it was the neutrino. The observation of neutrinos is hard given its very low interaction rate with matter. However, it was found recently that neutrinos oscillate, which means thay change from one flavor to another. This means neutrinos have mass, something which was not foreseen in the particle physics standard model. Detailled studies of the nature and mass of the neutrinos is a very active field in the high energy physics community, given the huge impact these will have on our understanding of Nature. ANDES will host experiments investigating these lines.
In addition to the participation of the ANDES laboratory in the worldwide campaign on the nature of neutrinos, the location of ANDES as only underground laboratory in the southern hemisphere opens the door to totally new experiments.
Nowadays, many experiments detect neutrinos produced by a particle accelerator located at hundreds of kilometers of distance.
The distance of ANDES to the main accelerators can be used to its advantage. As an example, the propagation of neutrinos in matter induces specific effects on the oscillations (MSW effect), that at a distance of 7500km cancel many terms allowing a precision measurement of factors that are very difficult to measure at other distances.
ANDES is located at 7650km of Fermilab, in Chicago, one of the three main worldwide particle accelerators, allowing such a measurement. Furthemore, the neutrino beam of KEK, in Japan, would have to cross 12500km to reach ANDES, meaning it would have to go through the core of the Earth, allowing measurements on the MSW effect no other neutrino experiment could produce.
Finally, ANDES could contribute to the new field of geoneutrino detection. Geoneutrinos are neutrinos produced in the Earth in the decays from the planet own radioactive matter.
These geoneutrinos seem necessary to understand the thermal equilibrium of the Earth. While very difficult to detect in Europe, Japan or Northern America due to the neutrino background produced by nuclear reactors, they would be clearly visible in ANDES.