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Nuclear Theory·nucl-th

Friday·December 24, 2021

11 papers—5 primary·6 cross-listed

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  1. 01

    Resonant tunneling of deuteron-triton fusion in strong high-frequency electromagnetic fields

    Binbing Wu · Hao Duan · Jie Liu

    We investigate deuteron-triton (DT) fusion in the presence of linearly polarized strong electromagnetic fields in high-frequency limit, in which a complex spherical square-well potential is exploited to describe the nuclear potential. Within the framework of the Kramers-Henneberger (KH) transformation, we have calculated the total and angular differential fusion cross sections by investigating the asymptotical phase shifts of the Coulomb wavefunctions. With introducing a dimensionless quantity of representing the ratio of the particle quiver oscillation amplitude to the radius of nuclear potential, we find that, even though the tunneling probability of passing through the Coulomb repulsive potential keeps almost identical to that in the absence of electromagnetic fields, the peak of total fusion sections shows an apparent shift from the well known value of 110 keV to 78 keV for . The angular differential cross sections also show some resonance peaks that shift from zero inclination angle to with increasing the parameter . The corresponding astrophysical -factors are found to be enhanced by several times in amplitudes. With the help of Wentzel-Kramers-Brillouin (WKB) approximate wavefunctions, the shape-resonance tunneling mechanism of the above findings are uncovered and some implications are discussed.

    nucl-thPRC(2022)·11 citations
  2. 02

    Electrical conductivity of the quark-gluon plasma from the low energy limit of photon and dilepton spectra

    Stefan Floerchinger🇩🇪 · Charlotte Gebhardt🇩🇪 · Klaus Reygers🇩🇪

    Fluid dynamic considerations are used to determine the electric current spectral density in the regime of small energies and momenta. The spectral density in this regime is parameterized by the electric conductivity, the charge susceptibility, and the relaxation time for the electric current, which is needed for relativistic causality. Experimentally, the spectral function can be accessed through the production rates of photons and dileptons in the expanding quark-gluon plasma. We use fluid dynamic simulations of high energy nuclear collisions, together with the transport limit of the spectral density, to obtain photon and dielectron spectra for different values of the conductivity and relaxation times. The yields of photon and dileptons produced in the plasma are compared to the background from decays of short-lived hadrons. We discuss how experiments can constrain the electrical conductivity and associated relaxation time of the quark-gluon plasma.

    nucl-thhep-phnucl-exPLB(2023)·18 citations
  3. 03

    Bose-Einstein condensation in finite drops of alpha particles

    L. M. Satarov · I. N. Mishustin · H. Stoecker

    Ground-state properties of finite drops of alpha particles (Q-balls) are studied within a field-theoretical approach in the mean-field approximation. The strong interaction of alphas is described by the scalar field with a sextic Skyrme-like potential. The radial profiles of scalar- and Coulomb fields are found by solving the coupled system of Klein-Gordon and Poisson equations. The formation of shell-like nuclei, with vanishing density around the center, is predicted at high enough attractive strength of Skyrme potential. The equilibrium values of energy and baryon number of Q-balls and Q-shells are calculated for different sets of interaction parameters. Empirical binding energies of alpha-conjugate nuclei are reproduced only if the gradient term in the Lagrangian is strongly enhanced. It is demonstrated that this enhancement can be explained by a finite size of alpha particles.

    nucl-thPRC(2022)·3 citations
  4. 04

    Artificial Intelligence Supported Shell-Model Calculations for Light Sn Isotopes

    Serkan Akkoyun · Abderrahmane Yakhelef

    The region around the doubly magic nuclide is very interesting for nuclear physics studies in terms of structure, reaction and nuclear astrophysics. The main ingredients in nuclear structure studies using the shell model are the single-particle energies and the two-body matrix elements. To obtain the former, experimental data of isotope spectrum are necessary. Since there is not enough experimental data, different approaches are used in the literature to obtain single-particle energies. In sn100pn interaction, the hole excitation spectrum was used in to determine neutron single-particle energies. The other approach is the use of the lightest isotope, , which figures the model space orbitals. In this study, we estimated the spectrum of the isotope by artificial neural network method in order to obtain neutron single-particle energies. After the training was carried out by using the experimental spectra of the nuclei around isotope, the spectrum was obtained. Subsequently, neutron SPEs of the model space orbitals are defined. Shell model calculations for isotopes are carried out and results are compared to the experimental data and results obtained using the widely used interaction in the region, sn100pn. According to the results, it is seen that the Sn isotope spectra obtained with the new SPE values are more compatible with the experimental data.

    nucl-thPRC(2022)·2 citations
  5. 05

    Angular Power Spectrum and Elliptic Flow from Event Maps in Heavy Ion Collisions

    Hannah Anderson🇺🇸 · Shengquan Tuo🇺🇸

    Azimuthal and polar angle distributions of particles produced in heavy ion collisions carry important information about the early state of the system and the evolution of the Quark Gluon Plasma. The pixelization code HEALPix was created by the Jet Propulsion Laboratory to analyze the cosmic microwave background. As has been shown using public data from the ALICE experiment, its two-dimensional representation of a sphere containing pixels of equal area has a broader application to heavy ion collisions. The angular power spectrum, an application of HEALPix, is directly related to the particle flow and is calculated through the angles theta and phi on the sphere. The elliptic flow is calculated from simulated AMPT events and publicly available CMS data. We show that HEALPix can be used to detect the presence of elliptic flow for lead-lead collisions and thus has broader applications in the study of QGP in heavy ion collisions.

    nucl-th0 citations

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first authorsco-authorsvia INSPIRE