CERN's ALICE experiment at the Large Hadron Collider has solved a long-standing mystery in nuclear physics, clarifying how fragile atomic nuclei called deuterons form in extreme environments. Scientists found these delicate particles do not survive initial high-energy collisions. Instead, they form later as the super-hot "fireball" cools. This breakthrough has significant implications for understanding cosmic rays and the search for dark matter in the universe.
A Long-Standing Puzzle Solved
For years, physicists observed deuterons and their antimatter counterparts, antideuterons, emerging from particle collisions at the Large Hadron Collider (LHC). This was puzzling because the LHC creates temperatures over 100,000 times hotter than the Sun's core. Deuterons consist of just one proton and one neutron, held together by a weak binding force. Under such intense heat, these fragile nuclei should break apart almost instantly.[sciencedaily+2]
The ALICE team's new findings show a different process. Deuterons are not surviving the initial chaos of the collisions. They are born later, after the extremely hot environment cools down. Protons and neutrons needed to create these tiny nuclei are released when ultra-short-lived, high-energy particles decay. Once freed, these particles can then join together to form deuterons. This newly identified process explains roughly 90 percent of the observed deuterons and antideuterons.[sciencedaily+4]
Unlocking Cosmic Ray Secrets
This discovery is crucial for making sense of cosmic rays, which are very energetic protons and atomic nuclei that hurtle through space. Cosmic rays often collide with other nuclei in outer space, similar to the high-energy collisions recreated at CERN. Scientists need to know which formation mechanisms are possible when predicting how light nuclei form in these cosmic events.[thehindu+4]
By building reliable models for how light nuclei and anti-nuclei are produced, physicists can better interpret cosmic-ray data. This is vital for astronomy research and for understanding signals from space. The ALICE team stated that these findings not only explain a puzzle in nuclear physics but also have far-reaching implications for astrophysics and cosmology.[thehindu+2]
Implications for Astrophysics and Dark Matter
The production of light nuclei and antinuclei is not limited to particle accelerators. These particles are also created when cosmic rays interact with the interstellar medium. Furthermore, they may even be formed in processes involving the mysterious dark matter that pervades the universe.[thehindu+1]
Understanding how deuterons form in these extreme conditions helps scientists distinguish signals coming from different sources in space. This improved understanding allows researchers to look for possible dark-matter signals more accurately. The research provides a clearer picture of fundamental nuclear processes, which is essential for advancing our knowledge of the universe.[thehindu+1]
