South African researchers have defied convention, pioneering a groundbreaking method to unveil the secrets of Dark Matter, reshaping the future of astrophysics.
Johannesburg, South Africa (29 November 2023) – One of the most elusive enigmas in the vast expanse of our universe is Dark Matter and South African researchers seem to be at the forefront of this unprecedented discovery approach.
Comprising roughly a quarter of the cosmos, Dark Matter remains an enigmatic force that doesn’t readily interact with ordinary matter. While its existence has been affirmed through astrophysical and cosmological observations, the quest for experimental evidence has been a challenge, captivating the minds of physicists globally for decades.
In a groundbreaking development, researchers from the University of the Witwatersrand in Johannesburg, South Africa, have embarked on a pioneering journey to unravel the secrets of Dark Matter. Professor Deepak Kar, hailing from the School of Physics at Wits, along with his former PhD student Sukanya Sinha, now a postdoctoral researcher at the University of Manchester, have devised a novel approach that challenges conventional wisdom in the search for Dark Matter.
“This is the essence of why we delve into basic science, delving into the deepest mysteries of the universe. The Large Hadron Collider at CERN stands as the grandest experiment ever constructed, utilizing particle collisions to simulate conditions akin to the Big Bang, providing a unique opportunity to seek clues about Dark Matter,” explains Professor Kar.
Traditionally, researchers have focused their efforts on the search for Weakly Interacting Massive Particles (WIMPs) in collider experiments.
However, as Professor Kar notes, “As no evidence of WIMPs has been found, we realized that the search for Dark Matter required a paradigm shift.”
The duo’s curiosity led them to explore a new detector signature known as “semi-visible jets,” a concept hitherto overlooked by the scientific community.
Professor Kar elaborates, “We wondered if Dark Matter particles are actually produced within a jet of standard model particles.”
In high-energy proton collisions, the aftermath often manifests as a collimated spray of particles, forming what scientists term “jets.” Semi-visible jets emerge when hypothetical dark quarks partially decay into standard model quarks and partially into stable dark hadrons, constituting the elusive “invisible fraction” of Dark Matter. The imbalance of energy or missing energy in the detector becomes apparent when all the jets are not perfectly balanced, with the direction of the missing energy aligned with one of the semi-visible jets. The quest for semi-visible jets presents a unique set of challenges, as this event signature can also be attributed to mis-measured jets in the detector. Nevertheless, Kar and Sinha’s innovative approach to searching for Dark Matter opens new avenues in the quest for its existence.
Sinha, reflecting on her contribution, emphasizes, “Even though my PhD thesis does not unveil the discovery of Dark Matter, it establishes the first and stringent upper bounds on this production mode, already inspiring further studies.”
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