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Dark matter is not known to interact with ordinary baryonic matter and radiation except through gravity, making it difficult to detect in the laboratory. The most prevalent explanation is that dark matter is some as-yet-undiscovered subatomic particle , such as either weakly interacting massive particles (WIMPs) or axions . [ 12 ]
Since this C-inversion does not affect gravitational mass, the CPT theorem predicts that the gravitational mass of antimatter is the same as that of ordinary matter. [5] A repulsive gravity is then excluded, since that would imply a difference in sign between the observable gravitational mass of matter and antimatter. [citation needed]
Dark matter is called ‘dark’ because it’s invisible to us and does not measurably interact with anything other than gravity. It could be interspersed between the atoms that make up the Earth ...
Collisionless: Dark matter particles interact with each other and other particles only through gravity and possibly the weak force; Dark matter constitutes about 26.5% [11] of the mass–energy density of the universe.
Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter.. There exists no formal definition of a WIMP, but broadly, it is an elementary particle which interacts via gravity and any other force (or forces) which is as weak as or weaker than the weak nuclear force, but also non-vanishing in strength.
As "dark matter", baryonic dark matter is undetectable by its emitted radiation, but its presence can be inferred from gravitational effects on visible matter. This form of dark matter is composed of "baryons", heavy subatomic particles such as protons and neutrons and combinations of these, including non-emitting ordinary atoms.
The dark matter can be modeled as a scalar field using two fitted parameters, mass and self-interaction. [4] [5] In this model the dark matter consists of an ultralight particle with a mass of ~10 −22 eV when there is no self-interaction.
An example of a hot dark matter particle is the neutrino. [5] Neutrinos have very small masses, and do not take part in two of the four fundamental forces, the electromagnetic interaction and the strong interaction.