In a groundbreaking development, scientists from the Raman Research Institute (RRI), an autonomous institute under the Department of Science and Technology (DST), have unveiled a novel approach to unravel the mysteries of cold dark matter (CDM). Comprising 25 percent of the current Universe, CDM has long perplexed scientists due to its elusive nature and enigmatic interactions.
The prevailing cosmic makeup consists of nearly 70 percent dark energy and 25 percent dark matter, elements shrouded in profound mystery. The elusive nature of dark matter, constituting an immense portion of the Universe, has spurred scientists to explore its characteristics and interactions. However, the existing models—particle physics and cosmological—have often presented conflicting insights into CDM.
The cosmological model offers a framework for understanding the vast-scale structures and dynamics of the universe, while the particle physics model delves into the fundamental building blocks of the universe. The two models, crucial for deciphering CDM, have not always aligned in their observations, leading to challenges in understanding the constituents of cold dark matter.
A prominent candidate in the quest for CDM is the Weakly Interacting Massive Particle (WIMP), a particle emerging naturally in extensions of the standard model of particle physics. Despite being a promising candidate, experimental searches for WIMP, such as those in Xenon-based experiments, have not yielded conclusive results. The theoretical framework of WIMP, often considered massive and stable, faced challenges as it conflicted with experimental data.
In a recently published paper, Professor Shiv Sethi from RRI, along with collaborator Abineet Parichha, has introduced a paradigm shift by relaxing certain assumptions about WIMP stability. By considering an unstable WIMP that decays, the researchers demonstrated its compatibility with existing observational and experimental constraints on the nature of cold dark matter. This innovative approach challenges the assumption of a massive, stable WIMP and opens up new possibilities for understanding dark matter.
“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,” explained Prof. Sethi, a senior faculty member of Astronomy and Astrophysics at RRI.
This research not only revalidates the viability of the WIMP model under revised assumptions but also points towards exciting possibilities in the dark matter sector, especially in light of data from space telescopes like the James Webb Space Telescope (JWST). The Indian scientists’ innovative approach charts a new course in the quest to decipher the secrets of dark matter, bridging the realms of particle physics and cosmology.