⚛️ A "mirror world" to explain the mystery of dark matter

The Universe still holds many mysteries, and among them, dark matter remains one of the most intriguing. This invisible substance makes up the majority of cosmic matter, influencing the rotation of galaxies and the large-scale structure of the cosmos, without us knowing precisely what it is made of.

Recent work by Professor Stefano Profumo from the University of California, Santa Cruz, provides innovative insights into its possible origins, relying on well-established physical theories but pushing them to their limits.


In a first study published in Physical Review D, Profumo explores the hypothesis of a 'hidden sector' of the Universe, a kind of mirror world with its own particles and forces, invisible to us but obeying the same physical laws.

Inspired by quantum chromodynamics, which describes how quarks are bound within protons and neutrons, this scenario postulates the existence of 'dark quarks' and 'dark gluons' forming massive composite particles. Under certain primordial conditions, these could gravitationally collapse into tiny stable black holes, thus explaining dark matter without requiring new detectable exotic particles.

A second study by the same author, also published in Physical Review D, examines a different mechanism: the production of dark matter through the accelerated expansion of the early Universe. Profumo uses quantum field theory in curved spacetime to show that the cosmic horizon, analogous to that of a black hole, could have 'radiated' stable particles during a phase of rapid expansion.

This purely gravitational approach does not rely on any assumed interaction with ordinary matter and offers a range of possible masses for dark matter, enriching conventional models under pressure from negative experimental results.

These two theories, although speculative, are part of a research tradition at UC Santa Cruz, where the interconnection between theory and observation has long been valued. Profumo emphasizes that they remain grounded in known physics, such as gauge theories or general relativity, while opening new perspectives for linking particle physics to cosmological phenomena.

The implications of this work could be profound, offering testable frameworks for future cosmological observations and high-energy physics experiments. By exploring bold but calculable ideas, the researcher aims to advance our understanding of the dark Universe without resorting to ad hoc hypotheses, respecting the fundamental principles of science.