Re-verification of the Gallium anomaly

Believe it or not, there are still some things that science just cannot fully explain, e.g., politics, my neighbor's cat, etc. The Gallium anomaly is one of them. When science stumbles across unpredicted results, things sometimes get very interesting and fun. Understanding unpredicted data is where new findings come from. Sometimes a Nobel Prize pops out. 

Here is the Gallium anomaly explained in simple terms: One isotope of Germanium, ⁷¹Ge, is radioactive. When a ⁷¹Ge atom decays, it is supposed to decay into a Gallium-71 atom, ⁷¹Ga. That is what the standard model of the universe predicts. But decades of measurements find that about 20% less ⁷¹Ga is produced than predicted. What happened to the other 20%? 

A paper in the nuclear physics journal, Phys. Rev. C 109, 055501 (May 30, 2024), has this abstract:

What this research showed, with greater precision than before, is that the rate at which ⁷¹Ge atoms decay is the same as what was previously measured with less accuracy.  Therefore, a postulated incorrect rate of decay cannot explain the Gallium anomaly. The anomaly is now re-verified as a true anomaly, not an experimental error. The missing 20% of ⁷¹Ga atoms has to have another explanation. 

Quanta magazine discusses the anomaly and the possibilities for new science:

Deep in the Caucasus Mountains, on the border between Russia and Georgia, an unusual experiment is taking place. In an underground lab shielded by a mountain of rock, highly radioactive material sits inside a vat of liquid [germanium?], blasting out particles called neutrinos that break the germanium down into atoms of gallium. [I am completely confused by the 2nd sentence here]

The goal is to resolve a little-known mystery of physics: the gallium anomaly. [but not little-known to the well-informed folks at Snowflake's Forum, right?]

Physicists have worked to rule out possible mismeasurements or inaccuracies that could explain the anomaly. Now they’ve eliminated another one. Eric Norman, a nuclear physicist at the University of California, Berkeley, and colleagues have announced that one possible solution, an incorrect calculation of the half-life of germanium, can’t be the cause.

“The half-life is correct,” Norman said. “This is not the explanation for the gallium anomaly.”

That leaves few possibilities. One is that some still-unknown experimental defect caused the anomaly. Perhaps a different mismeasurement is throwing things off, or a misunderstanding of nuclear physics. Or maybe, just maybe, the anomaly points to a monumental discovery, the existence of a new type of elementary particle called a sterile neutrino. Sterile neutrinos were initially proposed to explain why the masses of the three known neutrinos are so tiny, but they could also account for at least some of the invisible “dark matter” that fills the cosmos.

Sterile neutrinos and dark matter -- what a total hoot! My science genes are all fired up now.

Note: There is a slew of Germanium isotopes, ⁷¹Ge is just one of them.

⁷¹Br decays into ⁷¹Se, which decays into ⁷¹As, which decays into ⁷¹Ge, which decays into ⁷¹Ga, but only at a rate of 80% of what is predicted. 

Just for the halibut, two ways to get ⁷¹Ga, one from ⁷¹Zn, and the other from ⁷¹Ge.

Zn = zinc

Br = bromine

As = arsenic

Cu = copper

By Germaine: Not a nuclear physicist