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Case for axion origin of dark matter gains traction:
The existence of dark matter has been confirmed by several independent observations, but its true identity remains a mystery. According to this study, axion velocity provides a key insight into the dark matter puzzle. Previous research efforts have successfully accounted for the abundance of dark matter in the universe; however certain factors, such as the underproduction of axions with stronger ordinary matter interactions, remained unexplored.
By assigning a nonzero initial velocity to the axion field, the team discovered a mechanism—termed kinetic misalignment—producing far more axions in the early universe than conventional mechanisms. The motion, generated by breaking of the axion shift symmetry, significantly modifies the conventional computation of the axion dark matter abundance. Additionally, these dynamics allow axion dark matter to react more strongly with ordinary matter, exceeding the prediction of the conventional misalignment mechanism.
"The extensive literature on the axion was built upon the assumption that the axion field is initially static in the early universe," stated Keisuke Harigaya of the Institute for Advanced Study. "Instead, we discovered that the axion field may be initially dynamic as a consequence of theories of quantum gravity with axions."
Journal Reference:
Raymond T. Co, Lawrence J. Hall, Keisuke Harigaya. Axion Kinetic Misalignment Mechanism [open], Physical Review Letters (DOI: 10.1103/PhysRevLett.124.251802)
(Score: 1) by anubi on Saturday June 27 2020, @12:17PM (3 children)
How do we distinguish this from burned out stars?
They would still have mass, but no lumenosity, making them difficult to see.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 3, Interesting) by khallow on Saturday June 27 2020, @12:41PM
For me, the biggest problem with exotic particle dark matter is how do you get it moving slow enough that it can be captured and concentrated by a galaxy? For example, typical neutrinos have many orders of magnitude over the kinetic energy they need to escape from the galaxy and to our knowledge, they don't interact with anything. You couldn't get a cloud of neutrinos distorting galaxy gravitational fields, because they wouldn't stick around.
(Score: 4, Informative) by zocalo on Saturday June 27 2020, @12:47PM
Dark Matter, is generally thought of as a more diffuse distribution of mass - dust, gas, atomic particules - that we are currently unable to identify beause it's not emitting or reflecting enough light/energy for us to detect, but being distributed over a much larger area. We think of stars as large objects, but space is still almost entirely empty; if you distribute a stellar mass with the typical density of a stellar dust or gas cloud, it's going to occupy a volume that measures light years on a side. Same overall mass, but much less likely to have an appreciable impact of a stellar orbit, let alone one that we can detect.
UNIX? They're not even circumcised! Savages!
(Score: 0) by Anonymous Coward on Saturday June 27 2020, @06:44PM
maybe when one of those entities consciously couples with a black hole, whence that disturbance in the force is eventually detected by LIGO?
(wait, that was in the news this week... an entity was detected after merging with a black hole. it was speculated to be a black hole smaller than current idea of smallest black hole or a 'dark' neutron star)