Finding a needle in a haystack might prove easier than finding the most accurate measure of gravitational waves, telltale ripples in space-time created when massive black holes crash into each other. Yet a University of Mississippi physicist and his team have made significant advances in that direction.

Leo Chaim Stein, UM assistant professor of physics and astronomy, has been working with Keefe Mitman, a graduate student at the California Institute of Technology, and Macarena Lagos, a postdoctoral researcher at Columbia University, to precisely model gravitational waves that result from these cosmic collisions.

Stein, Mitman and Lagos detail their findings in “Nonlinearities in black hole ringdowns,” an article published Feb. 21 in the journal Physical Review Letters. The article was selected as an “Editor’s suggestion,” a designation given to only about 15% of all papers and reserved for those that are “particularly important, interesting and well-written.”

We want to mathematically model how black holes ‘ring down’ like a bell, because we can use the frequencies in the ringdown to test Einstein’s theory of gravity, general relativity,” Stein said.

UM is part of the Laser Interferometer Gravitational-Wave Observatory, or LIGO, Scientific Collaboration. The LIGO collaboration, working with the European-based Virgo interferometer, first detected gravitational waves in 2015 and have continued to study the phenomena.

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University of Mississippi physicist Jake Bennett studies a group of fleeting subatomic particles in hopes of advancing understanding of the fundamental building blocks that make up matter in the universe, and he is part of a team that has precisely measured the lifespan of one such particle.

Bennett is part of an international group studying charmed baryons, which are similar to protons and neutrons, but contain heavy second-generation quarks not seen in typical matter. These particles, referred to as Λ_c⁺, can only exist in high-energy environments such as the universe right after the big bang or in particle accelerators, and they decay, or break down into smaller particles, within fractions of a second.

Physical Review Letters published Bennett’s most recent results, “Measurement of the Λ_c⁺ Lifetime,” on Feb. 21.

His work uses data from the Belle II experiment, a global collaboration of physicists and engineers dedicated to studying subatomic particles and their interactions. Launched in 2018, Belle II uses an electron-positron collider at the SuperKEKBfacility in Tsukuba, Japan, to crash electrons and positrons into one another at close to the speed of light.

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Congratulations to Asst. Professor Leo C. Stein, who was selected as one of the 2023 Sloan Research Fellows! This is the first Sloan Fellowship awarded to a faculty member at the University of Mississippi. The University’s newsroom covered this story here: https://news.olemiss.edu/um-physicist-named-alfred-p-sloan-fellow/.