Research suggests that the germanium isotope really does have a half-life of 11 days

The search for the elusive neutrino takes many forms. Detectors consisting of many tons of gallium are used in various experiments because neutrino interactions can occur on the stable gallium-71 (⁷¹Ga) nucleus and transform it into a radioactive isotope of germanium (⁷¹Ge) with a half-life of 11 days which can then be observed with traditional radiation detectors.

However, the rate of ⁷¹Ge production from these interactions has been observed to fall short of expectations. This has emerged as what has been referred to as ‘the gallium anomaly’ – a significant discrepancy that occurs when electron neutrinos bombard gallium and produce the gallium. ⁷¹Ge.

This anomaly cannot be explained by current theories. As a result, it has given rise to speculation that it could be a feature that can transform the neutrino into other exotic particles, such as sterile neutrinos, which interact even less with matter than a normal neutrino; if confirmed, this would be a huge discovery.

It was recently suggested that this anomaly could instead be explained by something more mundane: an incorrectly measured half-life of the ⁷¹Ge core. This is because the predicted rate of neutrino interactions depends on this half-life.

To test this possible explanation for the gallium anomaly, a team of scientists from the Lawrence Berkeley and Lawrence Livermore national laboratories used the ⁷¹Ge half-life with a series of carefully performed measurements, including two measurements alongside other long-lived radioactive isotopes with known half-lives. The research appears in Physical assessment C.

The team managed to capture the ball ⁷¹Half-life to an accuracy approximately four times better than any previous measurement. The work eliminates the incorrect measurement of ⁷¹Ge as an explanation for the anomaly, which must therefore have another origin – possibly in the existence of a fourth neutrinotype, called a sterile neutrino.

“The new half-life obtained by our team confirmed the previous results but placed them on a much firmer basis, definitively ruling out the possible explanation that the missing neutrinos were instead due to an incorrect ⁷¹Ge half-life,” says LLNL scientist and lead author Nick Scielzo. “That’s why the gallium anomaly remains a true mystery — one that may still require some kind of unexpected new neutrino behavior to understand.”

Other LLNL authors of the study include Narek Gharibyan, Ken Gregorich, Brian Sammis, Jennifer Shusterman and Keenan Thomas.