Sat Mar 23, 2024 11:33 pm by globalturbo
CERN Physicists Measure Charge Radii of ‘Magic’ Nickel Nuclei
Jan 26, 2022 by News Staff / Source
A unique combination of experimental data from CERN’s Isotope mass Separator On-Line (ISOLDE) facility and state-of-the-art models has resulted in an excellent agreement between experiment and theory.
Frequency-time spectrum of (a) a 65Ni resonance, (b) the temporal ion-bunch structure, and (c) the laser-spectroscopic resonance spectrum; (d) a resonance of 70Ni. Image credit: Malbrunot-Ettenauer et al., doi: 10.1103/PhysRevLett.128.022502.
“The atomic nucleus is a tough nut to crack,” said CERN physicist Dr. Stephan Malbrunot and his colleagues.
“The strong interaction between the protons and neutrons that make it up depends on many quantities, and these particles, collectively known as nucleons, are subject to not only two-body forces but also three-body ones.”
“These and other features make the theoretical modeling of atomic nuclei a challenging endeavor.”
“In the past few decades, however, ab initio theoretical calculations, which attempt to describe nuclei from first principles, have started to change our understanding of nuclei,” they added.
“These calculations require fewer assumptions than traditional nuclear models, and they have a stronger predictive power.”
“That said, because so far they can only be used to predict the properties of nuclei up to a certain atomic mass, they cannot always be compared with so-called DFT calculations, which are also fundamental and powerful and have been around for longer.”
“Such a comparison is essential to build a nuclear model that is applicable across the board.”
Using a suite of experimental methods at the ISOLDE facility, including a technique to detect the light emitted by short-lived atoms when laser light is shone on them, Dr. Malbrunot and co-authors determined the charge radii of a range of short-lived nickel nuclei, which have the same number of protons, 28, but a different number of neutrons.
These 28 protons fill a complete shell within the nucleus, resulting in nuclei that are more strongly bound and stable than their nuclear neighbors.
Such ‘magic’ nuclei are excellent test cases for nuclear theories, and in terms of their radius, nickel nuclei are the last unexplored magic nuclei that have a mass within the mass region at which both ab initio and DFT calculations can be made.
Comparing the ISOLDE data with three ab initio calculations and one DFT calculation, the physicists found that the calculations agree with the data, as well as with each other, to within a theoretical uncertainty of one part in a hundred.
“An agreement at this level of precision demonstrates that it will eventually become possible to build a model that is applicable across the whole chart of nuclei,” Dr. Malbrunot said.
The results appear in the journal Physical Review Letters.
_____
S. Malbrunot-Ettenauer et al. 2022. Nuclear Charge Radii of the Nickel Isotopes 58-68,70Ni. Phys. Rev. Lett 128 (2): 022502; doi: 10.1103/PhysRevLett.128.022502
http://www.sci-news.com/physics/magic-nickel-nuclei-10490.html?utm_source=feedburner&utm_medium=email
Thanks to: http://www.sci-news.com
Jan 26, 2022 by News Staff / Source
A unique combination of experimental data from CERN’s Isotope mass Separator On-Line (ISOLDE) facility and state-of-the-art models has resulted in an excellent agreement between experiment and theory.
Frequency-time spectrum of (a) a 65Ni resonance, (b) the temporal ion-bunch structure, and (c) the laser-spectroscopic resonance spectrum; (d) a resonance of 70Ni. Image credit: Malbrunot-Ettenauer et al., doi: 10.1103/PhysRevLett.128.022502.
“The atomic nucleus is a tough nut to crack,” said CERN physicist Dr. Stephan Malbrunot and his colleagues.
“The strong interaction between the protons and neutrons that make it up depends on many quantities, and these particles, collectively known as nucleons, are subject to not only two-body forces but also three-body ones.”
“These and other features make the theoretical modeling of atomic nuclei a challenging endeavor.”
“In the past few decades, however, ab initio theoretical calculations, which attempt to describe nuclei from first principles, have started to change our understanding of nuclei,” they added.
“These calculations require fewer assumptions than traditional nuclear models, and they have a stronger predictive power.”
“That said, because so far they can only be used to predict the properties of nuclei up to a certain atomic mass, they cannot always be compared with so-called DFT calculations, which are also fundamental and powerful and have been around for longer.”
“Such a comparison is essential to build a nuclear model that is applicable across the board.”
Using a suite of experimental methods at the ISOLDE facility, including a technique to detect the light emitted by short-lived atoms when laser light is shone on them, Dr. Malbrunot and co-authors determined the charge radii of a range of short-lived nickel nuclei, which have the same number of protons, 28, but a different number of neutrons.
These 28 protons fill a complete shell within the nucleus, resulting in nuclei that are more strongly bound and stable than their nuclear neighbors.
Such ‘magic’ nuclei are excellent test cases for nuclear theories, and in terms of their radius, nickel nuclei are the last unexplored magic nuclei that have a mass within the mass region at which both ab initio and DFT calculations can be made.
Comparing the ISOLDE data with three ab initio calculations and one DFT calculation, the physicists found that the calculations agree with the data, as well as with each other, to within a theoretical uncertainty of one part in a hundred.
“An agreement at this level of precision demonstrates that it will eventually become possible to build a model that is applicable across the whole chart of nuclei,” Dr. Malbrunot said.
The results appear in the journal Physical Review Letters.
_____
S. Malbrunot-Ettenauer et al. 2022. Nuclear Charge Radii of the Nickel Isotopes 58-68,70Ni. Phys. Rev. Lett 128 (2): 022502; doi: 10.1103/PhysRevLett.128.022502
http://www.sci-news.com/physics/magic-nickel-nuclei-10490.html?utm_source=feedburner&utm_medium=email
Thanks to: http://www.sci-news.com
