Dark matter detector may have accidentally spotted the first detection of dark energy

A dark matter detector in Italy recorded 53 unexpected signals—possibly the first trace of dark energy.

Key Takeaways:

1. A dark matter detector may have unintentionally recorded the first direct evidence of dark energy.
2. Scientists propose that the signal could be caused by chameleon particles, a possible dark energy force.
3. The XENON1T experiment detected 53 unexplained events above the expected background noise.
4. Earlier theories suggested solar axions, but the new model points to dark energy instead.
5. Future experiments will determine whether this was a groundbreaking discovery or just a fluke.

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In a surprising turn of events, a dark matter detector may have accidentally captured the first direct evidence of dark energy—the mysterious force driving the universe’s accelerating expansion. Cambridge researchers propose that an unexplained signal in the XENON1T experiment might be due to “chameleon” particles, a theoretical component of dark energy.

A Mysterious Signal in XENON1T

Between 2016 and 2018, the XENON1T experiment in Italy aimed to detect dark matter particles by observing interactions in a tank filled with liquid xenon. If a dark matter particle collided with a xenon atom, the reaction would release light and electrons, which could be detected. However, when scientists analyzed the data, they found 53 unexpected events—far more than the predicted background noise of 232.

Initially, researchers suspected solar axions, hypothetical particles produced by the Sun. However, further analysis showed that an unrealistically high number of axions would be required to match the detected signal. This led Cambridge scientists to explore an alternative explanation: dark energy.

Chameleon Particles and the Case for Dark Energy

Dark energy is the force responsible for accelerating the universe’s expansion, but its nature remains unknown. One theory suggests that it could be carried by “chameleon” particles, named for their ability to change properties based on their surroundings. In dense environments, such as Earth, chameleons would have high mass but weak influence. In the near-empty expanses of space, they would have low mass but exert a stronger force. This would explain why dark energy affects galaxies but seems absent locally.

The Cambridge team modeled what would happen if chameleon particles were produced in a strongly magnetic solar region called the tachocline. The results closely matched the XENON1T signal, suggesting the detector may have picked up dark energy instead of dark matter.

However, the findings are not yet confirmed. Scientists stress that future experiments will need to replicate the excess events with a stronger signal to validate the discovery. If confirmed, this accidental detection could revolutionize our understanding of dark energy and its role in the cosmos.

The research was published in the journal Physical Review D.