International collaboration of scientists proves existence of anti-hypernucleus
(PhysOrg.com) -- A collaboration of international physicists, including three from Michigan State University, has proven the existence of the antimatter hypernucleus - more than 50 years after it was predicted to exist.
When the hypernucleus was discovered in 1952, scientists predicted its effective opposite must also exist. After decades of work, the new discovery at Brookhaven National Laboratory proves that these predictions were correct.
The antimatter hypernucleus was discovered by the STAR Collaboration, which is a group of 584 scientists from 54 institutions around the world. STAR team members at MSU include Terry Tarnowsky, visiting research associate, Hui Wang, a doctoral student in physics, and Gary Westfall, a University Distinguished Professor of physics.
The three MSU STAR team members are involved in the research that occurs at Brookhaven National Laboratory and the Relativistic Heavy-Ion Collider, or RHIC. The antimatter hypernucleus was created by high-energy collisions of gold ions at the RHIC.
Normal tritons are composed of a proton and two neutrons. Hypertritons are composed of a proton, a neutron and a lambda hyperon, which takes the place of one of the neutrons. The lambda particle is called a hyperon because it contains a strange quark.
Antihypertritons are composed of an anti proton, an antineutron, and an anti lambda hyperon. The fact that this new this anti-hypernucleus contains an antistrange quark will help physicists and cosmologists understand more about the inner workings of neutron stars and about what happened immediately after the big bang.
The RHIC collider is complimentary to the National Superconducting Cyclotron at MSU, says Tarnowsky. He notes that the lower energy of the cyclotron is used to study different kinds of reactions, but they both are exploring some of the fundamental questions of nuclear physics.
The STAR team at MSU is studying how the ratio of matter and antimatter fluctuates. “There isn’t much antimatter around today,” Tarnowsky says. “You can find it naturally occurring when neutron stars merge and when black holes engulf material.”
As energy increases, the ratio between matter and antimatter approaches 1:1. The current explanation for why the universe is primarily made of matter is that there was slightly more matter than antimatter when the Big Bang occurred. Tarnosky says continuing research will help scientists better understand what the universe looked like as it was being created. Heavy ion collisions will also be studied using much higher energies at the new Large Hadron Collider in Geneva, Switzerland, where the ratio of matter to antimatter is expected to be close to one.
Provided by Michigan State University
