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Nuclear Theory·nucl-th

Monday·June 15, 2020

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    Time-Dependent Generator Coordinate Method for Many-Particle Tunneling

    N. Hasegawa · K. Hagino · Y. Tanimura

    It has been known that the time-dependent Hartree-Fock (TDHF) method, or the time-dependent density functional theory (TDDFT), fails to describe many-body quantum tunneling. We overcome this problem by superposing a few time-dependent Slater determinants with the time-dependent generator coordinate method (TDGCM). We apply this method to scattering of two particles in one dimension, and demonstrate that the TDGCM method yields a finite tunneling probability even at energies below the Coulomb barrier, at which the tunneling probability is exactly zero in the TDHF. This is the first case in which a many-particle tunneling is simulated with a microscopic real-time approach.

    nucl-thPLB(2020)·14 citations
  2. 02

    A Statistical Description of Nuclear Reaction Models for Medical Radionuclides: the Paradigmatic Case of Sc Production with Thick Vanadium Targets

    M.P. Carante · F. Barbaro · L. Canton · A. Colombi · A. Fontana

    We have introduced a tool to describe in a simple and efficient way the outcomes of known nuclear reaction codes. It differs from the customary use where typically a specific single model is selected and the remaining disregarded. The use of simple statistical procedures allows to introduce a more general theoretical evaluation with quantitative uncertainty, constructed on the variability of the built-in theoretical models. We apply the technique to study the production of Sc (a radio-nuclide with potential theranostic applications in nuclear medicine) with a proton beam impinging on a thick natural Vanadium target. We find an energy range with significant production of Sc, and a minimum co-production of Sc, the radioactive contaminant that has to be avoided as much as possible because of its much longer half life than Sc (83.79 d vs 3.3492 d).

    nucl-thphysics.med-ph1 citation
  3. 03

    Neutron star inner crust: effects of rotation and magnetic fields

    Ivo Sengo · Helena Pais · Bruno Franzon · Constança Providência

    We study the role of the pasta phases on the properties of rotating and magnetized neutron stars. In order to investigate such systems, we make use of two different relativistic mean-field unified inner-crust--core equations of state, with a different density dependence of the symmetry energy, and an inner-crust computed within a Thomas-Fermi calculation. Special attention is given to the crust-core transition density, and the pasta phases effects on the global properties of stars. The effects of strong magnetic fields and fast rotation are computed by solving the Einstein-Maxwell equations self-consistently, taking into account anisotropies induced by the centrifugal and the Lorentz force. The location of the magnetic field neutral line and the maximum of the Lorentz force on the equatorial plane are calculated. The conditions under which they fall inside the inner crust region are discussed. We verified that models with a larger symmetry energy slope show more sensitivity to the variation of the magnetic field. One of the maxima of the Lorentz force, as well as the neutral line, and for a certain range of frequencies, fall inside the inner crust region. This may have consequences in the fracture of the crust, and may help explain phenomena associated with star quakes.

    nucl-thastro-ph.HEastro-ph.SRPRD(2020)·12 citations
  4. 04

    Improved method for the experimental determination of in-medium effects from heavy-ion collisions

    Helena Pais🇵🇹 · Rémi Bougault🇫🇷 · Francesca Gulminelli🇫🇷 · Constança Providência🇵🇹 · Eric Bonnet🇫🇷 · Bernard Borderie🇫🇷 · Abdelouahad Chbihi🇫🇷 · John D. Frankland🇫🇷 · Emmanuelle Galichet🇫🇷 · Diégo Gruyer🇫🇷 · Maxime Henri🇫🇷 · Nicolas Le Neindre🇫🇷 and 4 other authors

    The equation of state with light clusters for nuclear and stellar matter is determined using chemical equilibrium constants evaluated from the analysis of the recently published (XeSn) heavy ion data, corresponding to three reactions with different isotopic contents of the emission source. The measured multiplicities are used to extract the thermodynamic properties, and an in-medium correction to the ideal gas internal partition function of the clusters is included in the analysis. This in-medium correction and its respective uncertainty are calculated via a Bayesian analysis, with the unique hypothesis that the different nuclear species in a given sample must correspond to a unique common value for the density of the expanding source. Different parameter sets for the correction are tested, and the effect of the radius of the clusters on the thermodynamics and on the chemical equilibrium constants is also addressed. It is shown that the equilibrium constants obtained are almost independent of the isospin content of the analysed systems. Finally, a comparison with a relativistic mean field model proves that data are consistent with a universal in-medium correction of the scalar -meson coupling for nucleons bound in clusters. The obtained value, , is larger than that obtained in a previous study not including in-medium effects in the data analysis. This result implies a smaller effect on the binding energy of the clusters and, as a consequence, larger melting densities, and an increased cluster contribution in supernova matter.

    nucl-thastro-ph.HEJ.Phys.G(2020)·13 citations
  5. 05

    QCD2019 Workshop Summary

    S.J. Brodsky🇺🇸 · V.D. Burkert🇺🇸 · D.S. Carman🇺🇸 · J.P. Chen🇺🇸 · Z.-F. Cui🇨🇳 · M. Döring🇺🇸 · H.G. Dosch🇩🇪 · J.P. Draayer🇺🇸 · L. Elouadrhiri🇺🇸 · D.I. Glazier🇬🇧 · A.N. Hiller Blin🇺🇸 · T. Horn🇺🇸 and 17 other authors

    The topical workshop {\it Strong QCD from Hadron Structure Experiments} took place at Jefferson Lab from Nov. 6-9, 2019. Impressive progress in relating hadron structure observables to the strong QCD mechanisms has been achieved from the {\it ab initio} QCD description of hadron structure in a diverse array of methods in order to expose emergent phenomena via quasi-particle formation. The wealth of experimental data and the advances in hadron structure theory make it possible to gain insight into strong interaction dynamics in the regime of large quark-gluon coupling (the strong QCD regime), which will address the most challenging problems of the Standard Model on the nature of the dominant part of hadron mass, quark-gluon confinement, and the emergence of the ground and excited state hadrons, as well as atomic nuclei, from QCD. This workshop aimed to develop plans and to facilitate the future synergistic efforts between experimentalists, phenomenologists, and theorists working on studies of hadron spectroscopy and structure with the goal to connect the properties of hadrons and atomic nuclei available from data to the strong QCD dynamics underlying their emergence from QCD. These results pave the way for a future breakthrough extension in the studies of QCD with an Electron-Ion Collider in the U.S.

    ↳ hep-phhep-latnucl-exnucl-thIJMPE(2020)·76 citations
  6. 06

    Constraining gluon density of pions at large by pion-induced production

    Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

    The gluon distributions of the pion obtained from various global fits exhibit large variations among them. Within the framework of the color evaporation model, we show that the existing pion-induced production data, usually not included in the global fits, can impose useful additional constraints on the pion parton distribution functions (PDFs). In particular, these data can probe the pion's gluon densities at large . Existing pion-induced data covering a broad range of beam momenta are compared with next-to-leading-order QCD calculations using various sets of pion PDFs. It is found that data measured at forward rapidity and at sufficiently high beam momentum are sensitive to the large- gluon distribution of pions. The current data favor the Sutton-Martin-Roberts-Stirling and Gluck-Reya-Vogt pion PDFs, containing significant gluon content at large .

    ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·39 citations
  7. 07

    Acoplanarity of QED pairs accompanied by nuclear dissociation in ultra-peripheral heavy ion collisions

    James Daniel Brandenburg🇨🇳 · Wei Li🇺🇸 · Lijuan Ruan🇺🇸 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸 · Shuai Yang🇺🇸 · Wangmei Zha🇨🇳

    This paper investigates the transverse momentum broadening effect for electromagnetic production of dileptons in ultra-peripheral heavy ion collisions accompanied by nuclear dissociation. The electromagnetic dissociation probability of nuclei for different neutron multiplicities is estimated, which could serve as a centrality definition (i.e. impact parameter estimate) in ultra-peripheral collisions. In the framework of lowest-order QED, the acoplanarity of dilepton pairs is calculated for different neutron emission scenarios in ultra-peripheral collisions, indicating significant impact-parameter dependence. The verification of impact-parameter dependence is crucially important to understand the broadening effect observed in hadronic heavy-ion collisions.

    ↳ hep-phnucl-th23 citations

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first authorsco-authorsvia INSPIRE