The study suggests that the germanium isotope does indeed have an 11-day half-life

The search for the elusive neutrino takes many forms. Detectors composed of many tons of gallium are used in some experiments because neutrino interactions can occur in stable gallium-71 (⁷¹Ga) nucleus and converts it into a radioactive isotope of germanium (⁷¹Ge) with an 11-day half-life that can then be observed with traditional radiation detectors.

However, the rate of ⁷¹Ge production from these interactions is observed to be short of expectations. This has manifested itself as what is called the “gallium anomaly” – an important discrepancy that occurs when electron neutrinos bombard gallium and produce ⁷¹Ge.

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

Recently, it was suggested that this anomaly could instead be explained by something more common – a poorly measured half-life for 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 Lawrence Berkeley and Lawrence Livermore National Laboratories determined ⁷¹The half-life of Ge with a set of carefully performed measurements, including two performed side-by-side with other long-lived radioactive isotopes with known half-lives. The research appears in Physical examination C.

The team was able to identify ⁷¹Its half-life is made with an accuracy about four times better than any previous measurement. Work eliminates the mismeasurement of ⁷¹Ge as an explanation for the anomaly, which thus must have a different origin – perhaps in the existence of a fourth type of neutrino, called a sterile neutrino.

“The new half-life obtained by our team confirmed the previous results, but put it on a much firmer footing, definitively ruling out the possible explanation that the missing neutrinos were due to an error. ⁷¹Half of its life, – said LLNL scientist and lead author Nick Scielzo. “Therefore, the gallium anomaly remains a real mystery—one that potentially still requires 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.