Dark matter detector may have accidentally detected dark energy instead

It looks like a cool model, chameleon particles arising from a dynamical scalar field associated w/ dark energy. Looking at the paper [1], it's important to note that actually the solar axion model provides a better description of the xenon1t data. However, the axion model is disfavored due to constraints derived from observations of stellar evolution. The authors claim that while the chameleon model is a slightly worse fit to the xenon1t measurements, it is able to evade those astrophysical constraints. That is, those observations cannot be used as evidence for or against the chameleon model as the chameleon particles apparently aren't expected to have any impact on stellar evolution. I didn't read the paper closely enough to say, but this could be due to the characteristically weaker interaction of the chameleon particles in the vicinity of a dense/massive star. Or it could be due to a much more complicated reason!

[1] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.104.0...

Its exciting to see a hint of something from xenon1t. For many years these ultra low background dark matter experiments have been in a loop of measuring 0, setting a limit, then coming out with a more sensitive version of the experiment and repeating. It will be quite exciting if it doesn't turn out to be background and is seen in other devices.

The next version of this detector is called XENONnT and will have closer to 8 tons of xenon plus lower background. It's being built now. In these kinds of experiments the detection volume is typically position sensitive, which allows for events closer to the outside to be thrown out, as they are more likely to be caused by background. This self-shielding effect lowers effective background just by adding more material.