T-REX Project

T-REX stands for “TPCs for Rare Event eXperiments”. The goal of the T-REX project is to develop novel particle detectors with higher potential to search for “Rare Events” in astroparticle physics experiments.

We call “Rare Events” to particle physics phenomena that have a very low rate of occurrence, usually linked with new physics at the frontier of our current knowledge. Examples are the detection of Dark Matter particles, like WIMPs or axions in terrestrial experiments, or physics associated with the elusive neutrinos.

Nowadays we have evidence that most of the Universe (more than 95%) is made of unconventional stuff that we call Dark Matter and Dark Energy. We don’t know the nature of Dark Matter, but theorists have hypothesized several candidates. WIMPs and axions are the names of two of the most important candidates. The experimental discovery of one of these particles would be a ground-breaking discovery of modern science, with major consequences for Particle Physics, Astrophysics and Cosmology.

Neutrinos are standard particles (we know they exist) but they are very poorly known. In particular we know they have mass but don’t know how much. We don’t know if they are their own antiparticles (i.e. are neutrinos and antineutrinos the same particle?). These questions are important, as they have links with particular cosmological issues, like the puzzling matter-antimatter balance (i.e. why the Universe seems to be dominated by matter over antimatter?). The double beta decay, is a particular form of nuclear decay that may happen in a number of nuclei (for example in Xe-136). There is a non-standard mode of this decay called neutrinoless double beta decay that may happen only if neutrinos and antineutrinos are the same particle. The detection of such nuclear decay is the most powerful experimental tool to demonstrate this important feature of neutrinos.

Time Projection Chambers are special detectors that use gaseous media and very complex pixelised readouts to “image” the passing of particles through the chamber. It is a sort of 3D photographic camera, but to register subatomic particles. Therefore they are very appealing to search for “Rare Events” like the previously described, because the topological information of the “image” can be used to distinguish the “wanted event” among the millions other events that constitute the background. As part of the T-REX project we have build a number of prototypes to develop novel TPC techniques to assess the application of these detectors in different type of searches.

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