I have actually mostly quit composing stories about brand-new dark-matter prospects. Theoretical physicists keep creating more fancy situations to make dark matter more fascinating and less inert. Everything appears a bit forced. About the only thing that dark matter needs to do is offer mass. A particle that does not connect with electromagnetism at all fits the expense practically completely (and does almost absolutely nothing else).
Still, when there is speculative information to support it, I get thinking about dark-matter prospects once again. My cynicism aside, there are in fact a couple of outcomes spending time that appear tough to describe. For example, the hydrogen in the early Universe appears to have actually taken in less light than anticipated. The center of the galaxy releases an unforeseen quantity of gamma rays (though they may be due to common matter). And the neutrinos observed by the IceCube Neutrino Observatory in the Antarctic appear to be a bit unusual, too.
Neutrinos on ice
From all these, a current description for the IceCube information has actually captured my attention since it is fairly easy. This remains in contrast to a current proposition for a Bose-Einstein condensate of dark matter to describe the absence of hydrogen absorption, which appears hideously complicated.
IceCube is a huge neutrino detector in the Antarctic. For a while now, it has actually been taking a look at the high-energy neutrinos getting here from beyond the galaxy. The neutrinos are found in 2 various methods: by the track they leave in the detector and through the waterfall of light-emitting particles that they create when they hit the ice.
These 2 measurements do not appear to concur at the extremely greatest energies. Neutrinos can be found in 3 tastes– electron neutrinos, muon neutrinos, and tau neutrinos– and a single neutrino will oscillate amongst these identities as they take a trip. Designs anticipate that thanks to the large ranges the neutrinos have actually gone, there must be equivalent varieties of the various neutrinos. However IceCube sees even more electron neutrinos than anticipated.
To describe this inconsistency, a set of Danish theoreticians have actually proposed an undetectable neutrino decay path. In this case, a couple of of the tastes of neutrino decay into a particle called a marajon. The marajon is among a zoo of proposed dark-matter particles. This one now has 2 functions: it supplies the neutrino with mass, and it is produced by tau and muon neutrinos when they decay. This is a little a double win since the proof that neutrinos have mass is rather strong now– like from the taste oscillations from solar neutrinos, for example.
The great aspect of this design is that it in fact discusses a speculative inconsistency that is ending up being rather strong– the signal excess of electron neutrinos has about a one-in-10,000 opportunity of being a mishap at the minute. It is likewise great that the information is discussed by a rather very little adjustment: one dark matter particle of a sort that appears fairly well inspired by speculative information.
Now, neutrino decay into an undetectable particle is likewise extremely near not concurring with other speculative information (like supernova neutrinos). However the point is that the information does not dismiss neutrino decay yet. Or rather, the information permits 2 of the 3 neutrinos to decay, however one– the electron neutrino– needs to be steady.
The paper misses out on another essential aspect: we will require more information. The IceCube information set will have to get bigger so that we can be specific that the excess of electron neutrinos is genuine. (Beyond that, another information source would ready.) The issue there is that there are no other sources of high-energy neutrinos or big detectors to capture them, so it might be some time prior to we can validate that it’s something uncommon about the sources or detectors.
Physical Evaluation Letters, 2018, DOI: 101103/ PhysRevLett.121121802