Raman Research Institute (RRI) scientists have found a new approach to explore cold dark matter (CDM), a hypothetical dark matter that constitutes 25% of the current universe.
According to the Department of Science and Technology, in the current universe, nearly 70% constitutes dark energy whereas 25% is dark matter – about both of which there is scanty knowledge, till date.
The nature of dark matter and its interactions with the rest of the matter remains a mystery.
Scientists have, so far, been able to study a miniscule area of the universe which comprises everything -- the galaxies, stars, constellations, and meteors to name a few. It is very difficult to determine what the constituents of cold dark matter are.
The confusion escalated because the two models used to study CDM namely the particle physics model and the cosmological model were not in agreement.
The cosmological model provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate while the particle physics model describes the most basic building blocks of the universe. The success rate of the standard cosmological model has been good in recent decades.
One of the promising candidates of CDM is the Weakly Interacting Massive Particles (WIMP). Such particle arises naturally in extensions of the standard model of particle physics and predict the correct energy density of the CDM for a plausible range of interaction strength (WIMP miracle). However, inspite of intensive searches and orders of magnitude improvement in the sensitivity of lab experiments (e.g. Xenon based experiments), WIMP has not yet been detected. In addition, the parameter space suggested by the WIMP miracle had mostly been ruled out.
A recently published paper by RRI confirmed the relevance of WIMP by relaxing certain earlier assumptions and hence proved that theorising dark matter from particle physics was possible.
“We considered a model wherein the WIMP decays and one of the decay products of WIMPs acts as cold dark matter at late times. From a theoretical perspective, this scenario allows us to expand the permissible space of parameters. Additionally, we show that such a model leaves observable signatures on the Cosmic Microwave Background and the high redshift neutral hydrogen data,” said Prof. Shiv Sethi, senior faculty of Astronomy and Astrophysics at RRI.
