What is the temperature of cold & hot dark matter?

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Cold and hot dark matter do not have well-defined temperatures; instead, these terms describe their behavior and interaction characteristics. Hot dark matter is highly-relativistic and was once thought to interact more strongly, while cold dark matter is non-relativistic and interacts very weakly. The concept of temperature applies to ensembles of particles in collisionally dominated systems, not to individual particles. Therefore, discussing the temperature of dark matter is not meaningful in a traditional sense. Understanding these distinctions is crucial for studying the nature of dark matter in cosmology.
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what is the temperature of cold & hot dark matter?
 
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Neither has a well-defined temperature.
The terms 'hot' and 'cold' refer to characteristics of the dark matter, and how they behave---namely, hot dark-matter would be highly-relativistic (and in the past, was believed to be more strongly interacting); while cold dark matter is non-relativistic (and incredibly weakly interacting).

'Temperature' is only well defined in a collisionally dominated ensemble of particles that are well described by certain statistical distributions. It doesn't really make sense to say what the temperature of a single particle (for instance) is.
 

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