It is estimated that dark matter accounts for roughly 80% of all matter in the universe. Scientists have yet to fully crack its essential character, and it remains an enigma. A recent study by Stefano Profumo at the University of California, Santa Cruz, casts doubt on one such theoretical origin for dark matter. His groundbreaking ideas upend decades of orthodoxy surrounding this frequently misunderstood material. His study, published in Physical Review D, investigates the possibility that dark matter may not be an exotic particle but could emerge from conditions prevalent in the early universe.
Profumo’s research suggests that dark matter might be generated by the universe’s expanding “cosmic horizon,” a concept analogous to the event horizon of a black hole. This proposal represents an exciting new approach to probing the particle nature of dark matter. It moves beyond conventional models that have faltered without the benefit of experimental backing.
Exploring the Cosmic Horizon
Dark matter formation from the perspective of the cosmic horizon. As Profumo describes it, this new, expanding boundary could produce dark matter in manners entirely unthought of before.
“And they do so in a way that remains rooted in known physics—whether quantum field theory in curved spacetime, or the well-studied properties of SU(N) gauge theories—while extending them to new frontiers.” – Stefano Profumo
As such, this framework provides a testable hypothesis rooted in well-known physics to the age-old question, what is dark matter. Rather than searching for specific particles, Profumo’s theory changes the goal completely. This points to a deeper, more connected picture of how dark matter plays nice—or not—with the rest of the universe.
The Concept of a Hidden Sector
In his delightful and thought-provoking examination, Profumo proposes an important alternative approach. He proposes that dark matter comes from a hidden sector—from what he dubs as a hypothetical “mirror world” with its own particles and forces. This latter situation favors the interpretation of dark matter as heavy composite particles, referred to as dark baryons.
The concept of an unknown hidden sector has captured the imagination of many researchers. It complements neatly with ongoing discussions in the scientific community about the nature of dark matter. Most importantly, it inspires researchers to study new mechanisms outside of the established particle dark matter models. These traditional models are coming under increasing fire thanks to a series of recent experiments that have come up negative.
“Both mechanisms are highly speculative, but they offer self-contained and calculable scenarios that don’t rely on conventional particle dark matter models, which are increasingly under pressure from null experimental results.” – Stefano Profumo
By proposing these alternative frameworks, Profumo’s work adds depth to the ongoing discourse surrounding dark matter’s origins and its potential implications for cosmology.
UC Santa Cruz’s Legacy in Cosmology
It’s one of the hotbeds of University of California, Santa Cruz, cosmological research. It has done wonderful work in paving the path on which to develop the standard Lambda-Cold-Dark-Matter model. The institution has an established enthusiastic reputation on supporting synergies between theoretical and observational studies. This is particularly the case in the alluring fields of particle physics and astro-physics.
Michael Dine and Abe Seiden are two of the biggest names in the field of dark matter research. They have accomplished great things by pushing the frontier of both theory and experiment together. Dine is lauded for his pioneering work on the QCD axion, a leading dark matter candidate. At the same time, Seiden has had a huge impact on the design of high-energy physics experiments that study hadron structures.
Profumo’s research continues this legacy, using cutting-edge techniques to better calibrate and constrain particle dark matter models. His research reminds us that it’s crucial to continue asking questions about what we don’t even know lies beyond our immediate perception of the universe.
