Dark matter is a mystery. The only thing known is that it constitutes 85% of the matter of universe. Now Hungarian and German scientists have discovered some information on a dark matter particle that has been postulated, called the axion.
Scientists have discovered that axions can have mass between 50 and 1500 micro electron volts, that is, some ten billion times lighter than the electron. This computation has been published in the journal Nature. These calculations were done numerically using a (Bluegen/Q) super computer, JuQueen, housed in the Julich Supercomputer Centre in Germany.
Dark matter is known because of its weak interaction with matter and also as it is difficult to detect. Well rapidly rotating galaxies stand as its indirect proof. These galaxies cannot be held together merely by the gravitational pull of the matter they contain. There has to be an invisible stuff ‘dark matter’ to prevent them from flying apart with the force of their own energies.
Several particles have been hypothesized constituting dark matter- both massive as well as light weight – but none of the experiments have detected any such particle so far, directly.
Axions are particles proposed by extending quantum chromodynamics (QCD). The theory that describes “strong interactions,” the way quarks and gluons bond to form matter particles such as protons, neutrons etc. Though there are experiments to study them (for example: the Axion Dark Matter Experiment, ADMX) , there has been no real control on these until now.
The work sets a mass bound on the axions. And according to this, there should exist ten million such particles for every cubic centimeter of the universe. And also because axions occur in clumps there should be nearly a trillion axions per cubic centimeter in our galaxy, Milky Way.