DUNE takes another step towards completion in storied American Particle Physics journey
By Noah Heywood
In a major move towards its 2031-planned unveiling, the Deep Underground Neutrino Experiment (DUNE) project has begun the assembly of its far neutrino detectors. By sending tiny particles on an underground path from Illinois to South Dakota, it is possible that we can identify why there is more matter than antimatter in the universe.
A term coined by Italian Physicist Enrico Fermi in the heyday of quantum physics, the neutrino, by virtue of its name, ‘little neutral one’, is similar to the neutron because of its neutral electric charge. Due to this neutral charge and the fact that neutrinos are not made of quark particles, they hardly interact with matter in the universe at all, making them able to pass through anything and everything virtually unimpeded. Trillions pass through your body each second, most of them emanating from the Big Bang, The Sun and nearby stars.
This means physicists want to go deep underground to investigate neutrinos, far from the background effects of the high energy particles that form cosmic rays.
As a result of their elusive nature, measuring neutrinos directly is not possible – you need to look for the unique, predictable products of an interaction with another particle. Scientists at the far detector site in Sandford, South Dakota are using fifteen Kilotons of Argon to do this, a material that will be used in both its gaseous and liquid forms to capture as many neutrino interactions as it can. Argon represents a departure from the water used in the Super-Kamiokande neutrino experiment in Japan, as that experiment is optimised for observing neutrinos from space.
CP (Charge Conjugation Parity) Violation is the study of antiparticles that do not behave in theoretically ‘symmetrical’ ways to their counterpart matter particles. This is at the heart of contemporary particle physics – if DUNE observes CP violation in neutrino interactions, we’ll have experimental evidence that could explain why the universe isn’t made of equal parts matter and antimatter.
Physicists want to go deep underground to investigate neutrinos, far from the background effects of high energy particles from cosmic rays
So why is this stage in construction so exciting? Because it represents a commitment to completion. Ever since its cancellation in 1993, the Superconducting Super Collider particle accelerator experiment has loomed over American physics as a symbol of a missed opportunity. Several years after its demise, it featured in an episode of The West Wing, such was its legacy in American scientific politics. Even with roughly one quarter of its tunnels successfully bored on its North Texas site, a combination of financial irresponsibility and an unfortunate case of gastroenteritis hitting George Bush at the precise wrong moment meant the era-defining experiment never came to be, despite almost half of its initially proposed budget having been spent at the moment of cancellation. Future revolutionary discoveries in particle physics were then made at CERN in Switzerland, far far away from Waxahachie, Texas.
For the Americans however, there is hope in this new generation of particle experiments – the more that is built, the more likely completion is, and the closer we are to understanding the mass imbalance that is our universe.
Image: US Department of Energy via Wikimedia Commons
