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Nuclear Theory·nucl-th

Monday·November 13, 2023

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    Coherent interactions of a fast proton with a short-range correlation in the nucleus

    A.B. Larionov🇷🇺 · Yu.N. Uzikov🇷🇺

    Nuclear structure at short -distances is still poorly understood. In particular, the full quantum structure of the nucleus with a correlated -pair is a challenge to theory. So far, model descriptions have been limited to the average mean-field picture of the remaining nuclear system after removing the -pair. In the recent experiment of the BM@N Collaboration at JINR \cite{Patsyuk:2021fju}, the reactions and induced by the hard elastic scattering were studied. Here, or denote the undetected slow nucleon in the rest frame of . In contrast to the previous experiments, the residual bound nucleus was also detected which requires a new level of theoretical understanding. In the present work, we apply the technique of fractional parentage coefficients of the translationally-invariant shell model (TISM) to calculate the spectroscopic amplitude of the system where is the remaining nuclear system. The spectroscopic amplitude enters the full amplitude of a nuclear reaction. The relative wave function is no longer a free parameter of the model but is uniquely related to the internal state of . The interaction of the target proton with the -pair is considered in the impulse approximation. We also include the initial- and final state interactions of absorptive type as well as the single charge exchange processes. Our calculations are in a reasonable agreement with the BM@N data.

    nucl-thhep-exhep-phnucl-exPRC(2024)·2 citations
  2. 02

    Neutron Skins: Weak Elastic Scattering and Neutron Stars

    Juliette M. Mammei🇨🇦 · Charles J. Horowitz🇺🇸 · Jorge Piekarewicz🇺🇸 · Brendan Reed🇺🇸 · Concettina Sfienti🇩🇪

    The recently completed PREX-2 campaign - which measured the weak form factor of lead at an optimal momentum transfer - has confirmed that the neutron skin of lead is relatively large and has provided a precise determination of the interior baryon density of a heavy nucleus. In turn, the measured form factor can be related to various nuclear and neutron-star properties. Astrophysical observations by the NICER mission have benefited from improvements in flux, energy resolution, and notably, timing resolution. NICER has the capability to measure pulse profile data, which enables simultaneous mass-radius determinations. During the next decade, measurements in astrophysics, gravitational wave astronomy, and nuclear physics are expected to provide a wealth of more precise data. In this review we provide an overview of the current state of neutron skin measurements and offer insights into the prospects for the future.

    nucl-thnucl-exAnn.Rev.Nucl.Part.Sci.(2024)·17 citations
  3. 03

    Quantum Fluctuations Drive Angular Momenta in Nuclear Fission

    M. H. Zhou · S. Y. Chen · Z. Y. Li · M. S. Smith · Z. P. Li

    Quantum fluctuations are ubiquitous and play crucial roles across various scales and systems, such as the Big Bang, black hole dynamics, quantum phase transitions in microscopic many-body systems, and so on. Nuclear fission manifests as a complex nuclear shape stretching until it splits into fragments with substantial angular momenta, also exhibiting complex quantum fluctuations and specifically shape fluctuations. For over 40 years, researchers have puzzled how the fission fragment angular momenta are generated dynamically from (almost) zero spin, as well as the particular role played by quantum fluctuations. Here, for the first time, we report the quantum shape fluctuations that drive fragment angular momenta during nuclear fission, based on a global, microscopic, and dynamical simulation. The calculated probability distributions of fragment angular momenta are in good agreement with the experimental measurements, and the sawtooth-like mass dependence of average angular momenta is reproduced very well. It is noteworthy to find that the shape fluctuations -- multiple rotations, vibrations, and their couplings -- drive the generation and chaotic evolution of fragment angular momenta during fission fragment formation and induce strong correlations between angular momentum orientations of partner fragments at small, medium, and large opening angles (). Our work not only deepens the fundamental understanding of the nuclear fission mechanism but also has implications for the -ray heating problem in nuclear reactors and the synthesis of superheavy elements.

    nucl-th4 citations

Affiliations

first authorsco-authorsvia INSPIRE