Dark matter is one of the most complex mysteries of modern cosmology. On the one hand, astronomers have gathered a lot of supporting evidence from galaxy clustering statistics, gravitational lensing, and the cosmic microwave background, but on the other hand, there are no particles in the Standard Model of Particle Physics to explain dark matter, and we have not been able to detect its effects locally.
It’s a solid theory that we haven’t been able to pinpoint. This often means we’re just a breakthrough away from confirming or overthrowing dark matter. The good news is that there are several projects investigating dark matter, and one of them, the IceCube neutrino observatory, has just published a new result.
As a neutrino observatory, IceCube cannot detect dark matter directly, but it can detect local effects of neutrino-producing dark matter. One of the main patterns of dark matter particles is large particles that mostly interact with each other and weakly interact with ordinary matter particles. These Weakly Interacting Large Particles, or WIMPs, may be lurking in the Earth’s core.
If the WIMP model is correct, when dark matter collides with a massive object such as a planet or star, the collision with dense ordinary matter should slow it down and cause some WIMPs to become gravitationally trapped within the body. These WIMPs occasionally collide with each other, causing the neutrino-producing particles to decay. This means that there must be more neutrinos from the center of the Earth for IceCube to detect it.
In this study, the team analyzed decades of IceCube data and found no evidence of neutrino excess. Given the energy cross section of the IceCube detectors, this effectively excludes WIMPs with masses greater than 100 GeV or just over 100 proton masses. This result is consistent with other studies that also excluded high-mass WIMPs. Lower-mass dark matter particles are still possible, but we now have a long history of eliminating dark matter candidates.
There are plans to upgrade IceCube to increase its sensitivity, which will allow more dark matter testing to look for lower-mass WIMPs. This may finally allow us to detect dark matter locally, but our options are quickly running out. We’ve eliminated a few dark matter candidates for now, and we may need to consider alternatives such as altered gravity. But that’s another story. Source
Source: Port Altele
