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Nuclear Theory·nucl-th

Friday·October 9, 2020

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Light fragment and neutron emission in high-energy proton induced spallation reactions

    Hui-Gan Cheng · Zhao-Qing Feng

    The dynamics of high-energy proton-induced spallation reactions on target nuclides of Xe, Ni, Fe, Pb, W, Ta, Au and Cd, are investigated with the quantum molecular dynamics transport model. The production mechanism of light nuclides and fission fragments is thoroughly analyzed. The statistical code GEMINI is employed in conjunction to the model for managing the decay of primary fragments. For the treatment of cluster emission during the preequilibrium stage, a surface coalescence model is implemented into the model. It is found that the available data of total cross sections are well reproduced with the combined approach for the spallation reactions on both the heavy and light targets, i.e., Fe and Pb, while it is underestimated in the intermediate-mass-fragment region for the medium-mass target Xe. The energetic clusters are mainly contributed from the preequilibrium recognition, in which the quantum tunneling is taken into account. On the other hand, a fairly well overall description of light cluster and neutron emission is obtained and detailed discrepancies with respect to the experimental results are discussed. Possible modifications on the description of spallation reactions are stressed and compared with both recent experimental and theoretical results in the literature.

    nucl-thCPC(2021)·5 citations
  2. 02

    Search for determining the role of various physical properties of the fusion reactions in the proximity formalism

    Reza Gharaei · Elham Sarvari

    This work is focused on the analysis of the corrective effects of the temperature, surface tension, and nuclear matter density on the fusion barriers and also fusion cross sections caused by the original version of the proximity formalism (Prox.77 model) for 62 fusion reactions. A systematic comparison between the theoretical and empirical data of the height and position of the barrier as well as the fusion cross sections reveals that the agreement of these data improves by imposing each of the mentioned physical effects on the Prox.77 model for our selected mass range. Moreover, it is shown that the density-dependence effects have the most important role in improving the theoretical results of the proximity potential.

    nucl-th0 citations
  3. 03

    Partial wave correlations with uncertainties in the Two Nucleon System

    Adolfo Guevara🇪🇸 · Rodrigo Navarro Pérez🇺🇸 · Enrique Ruiz Arriola🇪🇸

    The NN scattering problem is usually analyzed in terms of partial waves and the corresponding coupled channel phase-shifts and mixing angles, but the available experiments induce correlations amongst the corresponding channels with different quantum numbers. Based on the Granada-2013 database we analyze the meaning and impact of those correlations taking into account both the purely statistical ones reflecting the primary experimental data uncertainties as well as the systematic ones exhibiting the ambiguities in the form of the potential representing the unknown nuclear force for distances below 3fm. We also ponder on the implications of fixing nuclear potentials by direct fits to the phase-shifts stemming from a full fledged partial wave analysis (PWA) inferred from experimental data.

    nucl-thPRC(2021)·2 citations
  4. 04

    Nuclear Pairing Gaps and Neutron Star Cooling

    Jin-Biao Wei · Fiorella Burgio · Hans-Josef Schulze

    We study the cooling of isolated neutron stars with particular regard to the importance of nuclear pairing gaps. A microscopic nuclear equation of state derived in the Brueckner-Hartree-Fock approach is used together with compatible neutron and proton pairing gaps. We then study the effect of modifying the gaps on the final deduced neutron star mass distributions. We find that a consistent description of all current cooling data can be achieved and a reasonable neutron star mass distribution can be predicted employing the (slightly reduced by about 40\%) proton 1S0 Bardeen-Cooper-Schrieffer (BCS) gaps and no neutron 3P2 pairing.

    nucl-thastro-ph.HEUniverse(2020)·9 citations
  5. 05

    Quasielastic Electromagnetic Scattering Cross Sections and World Data Comparisons in the {\fontfamily{qcr}\selectfont GENIE} Monte Carlo Event Generator

    Joshua L. Barrow🇺🇸 · Steven Gardiner🇺🇸 · Saori Pastore🇺🇸 · Minerba Betancourt🇺🇸 · Joseph Carlson🇺🇸

    The usage of Monte Carlo neutrino event generators (MCEGs) is a norm within the high-energy scattering community. The relevance of quasielastic (QE) energy regimes to oscillation experiments implies that accurate calculations of cross sections in this regime will be a key contributor to reducing the systematic uncertainties affecting the extraction of oscillation parameters. In spite of this, many MCEGs utilize highly phenomenological, parameterized models of QE scattering cross sections. Moreover, a culture of validation of MCEGs against prolific electron () scattering data has been historically lacking. In this work, we implement new cross sections obtained from nuclear ab initio approaches in GENIE, the primary MCEG utilized by the FNAL community. In particular, we utilize results from Quantum MC methods which solve the many-body nuclear problem in the Short-Time Approximation (STA), allowing consistent retention of two-nucleon dynamics which are crucial to explain available nuclear electromagnetic (electroweak) data over a wide range of energy and momentum transfers. This new implementation in GENIE is fully tested against the world QE electromagnetic data, finding agreement with available data below GeV of beam energy with the aid of a scaling function formalism. The STA is currently limited to study nuclei, however, its semi-inclusive multibody identity components are exportable to other many-body computational techniques such as Auxiliary Field Diffusion MC which can reach systems while continuing to realize the factorization contained within the STA's multinucleon dynamics. Together, these developments promise to make future experiments such as DUNE more accurate in their assessment of MCEG systematics, properties, and potentially empower the discovery of physics beyond the Standard Model.

    nucl-thhep-exhep-phnucl-exPRD(2021)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE