For ⟨0 +1 |, the mean (points) and confidence regions are the regions corresponding to 1σ (solid line) and 2σ (dotted line) | E3 | 3-1⟩ and ⟨3 −1 | E2 | 3 −1⟩Matrix elements (top), and ⟨0 +1 | E2 | 2 +1⟩ and ⟨2 +1 | E2 | 2 +1⟩Matrix elements (bottom). Credit: Physics Review Letter (2025). doi:10.1103/physrevlett.134.062502
International research cooperation led by the Nuclear Physics Group at the University of Surrey has overturned a long-standing belief that lead-208 (²⁰⁸pb) nuclei are completely spherical. This discovery has extensive implications to challenge basic assumptions about nuclear structures and to understand how the heaviest elements in the universe are formed.
Lead-208 is a “double magic” core, so it is very stable. And it’s the heaviest we know. However, a new study published in the physical review letter used a high-precision experimental probe to examine its shape, and it was not completely spherical, and the lead 208 core was slightly elongated, and it was a rugby ball (prorate spheroid). ) is found to be similar to ).
“We can combine four separate measurements using the world’s most sensitive laboratory equipment for this type of study,” said Dr. Jack Henderson, the lead researcher of the Department of Mathematics and Physics at Surrey University. This challenging observation surprised us. Theory presents exciting means for future research.”
Using a state-of-the-art Gretina Gamma Ray Spectrometer at the Argonne National Laboratory in Illinois, USA, scientists bombed lead atoms with a high-speed particle beam, accelerated to 10% of the speed of light. . The interaction created a unique gamma-ray fingerprint of the properties of the excitation quantum state of the lead 208 nuclei. In other words, the nucleus has been turned into energy.
Experiments suggest that nuclear structures are much more complex than previously thought, so theoretical physicists, including those from the Sally Nuclear Theory Group, are currently used to describe nuclei. We are reconsidering the following.
“These highly sensitive experiments shed new light on what we thought we were very well understood and understand why,” said Professor Paul Stevenson, a lead theorist of the University of Surrey research. It presented us with a new challenge: the oscillations of the lead 208 nuclear, when excited during the experiment, are less regular than previously assumed.
This research brings together teams of experts from major nuclear physics research centres in Europe and North America to challenge the fundamental principles of nuclear physics and creates a new path for the study of nuclear stability, astrophysics and quantum mechanics. It will open.
Details: J. Variations and collectivity of Henderson et al, Doubly Magic 208pb, Physical Review Letters (2025). doi:10.1103/physrevlett.134.062502
Provided by Surrey University
Citation: Unexpected shape of lead-208 nucleus prompts reevaluation of atomic nuclear models (2025, February 22) retrieved 22 February 2025 from https://phys.org/news/2025-02-unexpected-nucleus-prompts-reevaluation-atomic. HTML
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