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Nuclear Theory·nucl-th

Tuesday·January 2, 2024

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Radius extrapolations for two-body bound states in finite volume

    Anderson Taurence · Sebastian König

    Simulations of quantum systems in finite volume have proven to be a useful tool for calculating physical observables. Such studies to date have focused primarily on understanding the volume dependence of binding energies, from which it is possible to extract asymptotic properties of the corresponding bound state, as well as on extracting scattering information. For bound states, all properties depend on the size of the finite volume, and for precision studies it is important to understand such effects. In this work, we therefore derive the volume dependence of the mean squared radius of a two-body bound state, using a technique that can be generalized to other static properties in the future. We test our results with explicit numerical examples and demonstrate that we can robustly extract infinite-volume radii from finite-volume simulations in cubic boxes with periodic boundary conditions.

    nucl-thhep-latPRC(2024)·0 citations
  2. 02

    3D Multi-system Bayesian Calibration with Energy Conservation to Study Rapidity-dependent Dynamics of Nuclear Collisions

    Andi Mankolli🇺🇸 · Aaron Angerami · Ritu Arora · Steffen Bass · Shanshan Cao · Yi Chen · Lipei Du · Raymond Ehlers · Hannah Elfner · Wenkai Fan · Rainer J. Fries · Charles Gale and 39 other authors

    Considerable information about the early-stage dynamics of heavy-ion collisions is encoded in the rapidity dependence of measurements. To leverage the large amount of experimental data, we perform a systematic analysis using three-dimensional hydrodynamic simulations of multiple collision systems -- large and small, symmetric and asymmetric. Specifically, we perform fully 3D multi-stage hydrodynamic simulations initialized by a parameterized model for rapidity-dependent energy deposition, which we calibrate on the hadron multiplicity and anisotropic flow coefficients. We utilize Bayesian inference to constrain properties of the early- and late- time dynamics of the system, and highlight the impact of enforcing global energy conservation in our 3D model.

    nucl-thhep-phnucl-exEPJ Web Conf.(2024)·7 citations
  3. 03

    Magnetic dipole -ray strength functions of heavy nuclei in the configuration-interaction shell model

    Y. Alhassid · P. Fanto · A. Mercenne

    A low-energy enhancement (LEE) has been observed in the deexcitation -ray strength function (SF) of compound nuclei. The LEE has been a subject of intense experimental and theoretical interest since its discovery, and, if the LEE persists in heavy neutron-rich nuclei, it would have significant effects on calculations of r-process nucleosynthesis. Standard configuration-interaction (CI) shell-model calculations in medium-mass nuclei have attributed the LEE to the magnetic dipole SF but such calculations are computationally intractable in heavy nuclei. We review a combination of beyond-mean-field many-body methods within the framework of the CI shell model that enables the calculation of SF in heavy nuclei, and discuss the recent theoretical identification of a LEE in the magnetic dipole SF of lanthanide isotopes.

    nucl-thEPJ Web Conf.(2024)·0 citations
  4. 04

    Extracting spectra in the shell model Monte Carlo method using imaginary-time correlation matrices

    Y. Alhassid · M. Bonett-Matiz · C.N. Gilbreth · S. Vartak

    Conventional diagonalization methods to calculate nuclear energy levels in the framework of the configuration-interaction (CI) shell model approach are prohibited in very large model spaces. The shell model Monte Carlo (SMMC) is a powerful technique for calculating thermal and ground-state observables of nuclei in very large model spaces, but it is challenging to extract nuclear spectra in this approach. We present a novel method to extract low-lying energy levels for given values of a set of good quantum numbers such as spin and parity. The method is based on imaginary-time one-body density correlation matrices that satisfy asymptotically a generalized eigenvalue problem. We validate the method in a light nucleus that allows comparison with exact diagonalization results of the CI shell model Hamiltonian. The method is applicable to other finite-size quantum many-body systems that can be described within a CI shell model approach.

    nucl-thPRL(2024)·1 citation
  5. 05

    Bottom-hadron production in high-energy and heavy-ion collisions

    Min He🇨🇳

    The hadro-chemistry of bottom quarks produced in hadronic collisions encodes valuable information on the mechanism of color-neutralization in these reactions. We first compute the chemistry of bottom-hadrons in high-energy collisions employing statistical hadronization with a largely augmented set of states beyond the currently measured spectrum. This enables a comprehensive prediction of fragmentation fractions of weakly decaying bottom hadrons for the first time and a satisfactory explanation of the existing measurements in collisions at the LHC. Utilizing the bottom hadro-chemistry thus obtained as the baseline, we then perform transport simulations of bottom quarks in the hot QCD matter created in PbPb collisions at the LHC energy and calculate the pertinent bottom-hadron observables. The transverse momentum () dependent modifications of the bottom baryon-to-meson ratio () relative to their counterparts are highlighted as a result of bottom quark diffusion and hadronization in the Quark-Gluon Plasma (QGP). We finally summarize the heavy quark (charm vs bottom) diffusion coefficients as extracted from transport simulations and compare them to result from recent full lattice QCD computations.

    nucl-thEPJ Web Conf.(2024)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE