Recent experiments have renewed interest in the stability of protons. These three elementary particles exist within the very nuclei of hydrogen and oxygen, two key ingredients for life. Although seemingly immutable, our best theories in physics predict that protons must decay after a very long time. Scientists have run dozens of tests at the Super-Kamiokande observatory in Japan to look for signs of this rare and bizarre phenomenon. If it does exist, it is expected to have an immensely long lifetime, greater than \(10^{33}\) years.
This scientific mystery of understanding proton decay comes from its importance in particle physics and cosmology. As researchers Julian Heeck and Ian Shoemaker explain, this continuing inquiry is crucial. It might even unlock amazing new discoveries about the fundamental nature of reality.
The Search for Proton Decay
The Super-Kamiokande observatory has hosted one of the most active players in the international hunt for proton decay. Located in Taka, Japan, the facility uses advanced detection methods. These approaches track individual protons looking for evidence that they decay into other, previously unknown, elementary particles. In all of its ambitious attempts, the observatory has not so far detected unambiguous signals that protons are decaying.
Meanwhile, two other significant experiments, the Jiangmen Underground Neutrino Observatory (JUNO) and the Deep Underground Neutrino Experiment (DUNE), aim to detect lower-energy proton decays that might elude previous searches. Together their complementary designs provide unmatched capabilities to awaken researchers to the possibility of probing protons decaying anywhere inside the Earth’s crust.
“Lowering the detection threshold will open a much wider window to include decays that might have fallen through the cracks in earlier searches,” – Ian Shoemaker
Implications of Proton Decay
For one, if proton decay does happen, this can lead to the generation of new elementary particles. One interesting candidate is so-called “sterile neutrinos.” These exotic neutrinos, that interact only through gravity, could provide an explanation of the origin of neutrino mass. The detection of sterile neutrinos could deepen scientists’ understanding of fundamental physics and the universe’s evolution.
Thus research on proton decay is more than an academic exercise. It profoundly shapes our understanding of the most basic building blocks of all life, and what makes up our entire universe. The possibility of discovering new colored particles would overturn the current understanding and lead to a revolution in new innovations in physics.
“Our initial exploration of these signatures hints at many novel exciting opportunities for theoretical and experimental work that could lead to the groundbreaking discovery of new physics,” – Shoemaker
Future Directions
As experimental techniques improve and new facilities begin operations, researchers are confident that they will someday find conclusive evidence of proton decay. Clarifying the apparent conflict between these three results — Super-Kamiokande, JUNO, and DUNE — their combined findings could give a more complete picture of this elusive phenomenon.
A recent Paper published in Physical Review Letters reviews these historic and current efforts in proton decay experimentation. It’s important to understand how these experiments will yield priceless insights that drive particle physics in the best way. Beyond that, they’ll continue to sharpen our understanding of complicated cosmic events.