Forgotten particle could answer mystery of why we exist, say physicists

Why we exist is one of the strangest mysteries science has to grapple with, but scientists may have finally found the answer.A pair of theoretical physicists from the University of Southampton and the Indian Institute of Technology Kanpur claim that the key to our existence lies in a forgotten particle.The researchers argue that a strange entity known as the decoupled heavy neutrino could have played a vital role in shaping conditions in the early universe.And if it weren't for this often–overlooked particle, none of us would exist today.Co–author Dr Rishav Roshan, from the University of Southampton, told the Daily Mail: 'The decoupled right–handed neutrino has often been dismissed due to its weak interactions and high mass, making it appear irrelevant in many frameworks of particle physics.'However, its potential implications for cosmology and particle interactions had not been fully appreciated until recent studies.'Scientists believe that a forgotten particle known as a decoupled heavy neutrino could be the key to understanding why the universe as we know it exists today. Pictured: The Crab Nebula As scientists have tried to understand how the universe as we know it came into existence, they have uncovered a rather perplexing issue.According to our best theories, when matter was being created shortly after the Big Bang, every particle should have formed alongside a corresponding 'anti–particle'.When matter and antimatter come into contact, they are annihilated, leaving behind nothing but radiation.But this creates a serious problem when we look at the universe around us.'While the Big Bang should have produced equal amounts of both, we see that the universe is predominantly made of matter,' says Dr Roshan.'This asymmetry is crucial for our existence, as the presence of matter allows for the formation of stars, planets, and ultimately life, while the scarcity of antimatter raises questions about why it is so rare.'Scientists call this the matter–antimatter asymmetry, and understanding it is absolutely critical to learning why and how our universe came into existence.In their new paper, published in Physical Review Letters, the researchers suggest that the key is a rarely studied particle called the decoupled heavy neutrino. Some scientists believe that the universe contains three heavy neutrino particles that make up about 0.67 per cent of the mass in the universe What is antimatter? Antimatter is the mirror of ordinary matter.Normal atoms are made up of positively–charged nuclei orbited by negatively–charged electrons.However, their antimatter counterparts are the other way round.They have negative nuclei and positively–charged electrons, known as positrons.When matter and antimatter meet, they instantly annihilate each other, releasing a burst of detectable energy. A neutrino is a tiny, electrically neutral fundamental particle that very rarely interacts with other types of matter.To explain why the normal neutrino is so small, some theories of particle physics suggest that there must also be three heavy 'right–handed neutrinos'.The third 'decoupled' heavy neutrino has largely been ignored by scientists because it interacts so rarely with the rest of the universe.However, the researchers believe that it might have had a huge influence on how the universe developed in its very earliest stages.Because they interact so little and decay relatively slowly, these particles may have briefly contained more energy than all the radiation around them.That would have driven a period of rapid expansion in the early universe, which would have altered the temperature at which matter and antimatter were forming.Dr Roshan says: 'A neutrino, particularly a heavy right–handed neutrino, can influence the creation of matter and antimatter.'By affecting the interactions and decays of particles during the early universe, these neutrinos can help favour the production of matter over antimatter.' Neutrinos are a type of electrically neutral particle, which interacts with matter so rarely that scientists need to use specialised detectors sunk to the bottom of the ocean (pictured) to find them The researchers used theoretical models to examine the dynamics of these particle interactions in the early universe, and what impact these strange particles might have.According to their calculations, the presence of decoupled heavy neutrinos could create a very slight imbalance between matter and antimatter.If these processes created even slightly more particles than anti–particles, perhaps as little as one extra particle per billion, the leftover matter after annihilation would be enough to make everything we see in the universe today.Importantly, this is currently just a theoretical suggestion, and scientists haven't proven that these heavy neutrinos actually exist.However, the researchers remain optimistic that evidence to support their ideas could be found in the future.Dr Roshan says: 'This theory could be tested experimentally through upcoming gravitational wave detectors and particle physics experiments.'These tools may help us detect signatures related to heavy neutrinos and their role in the early universe, providing insights into the matter–antimatter asymmetry.'