Publications

Order by: publication date number of citations

• Effect of isospin averaging for $ppK^-$ kaonic cluster

  Branislav Vlahovic, Igor Filikhin

  SciPost Phys. Proc. 3, 040 (2020) · published 27 February 2020 | Toggle abstract · pdf

  The kaonic cluster $ppK^-$ is described by isospin-dependent $N{\bar K}$ potentials with significant difference between singlet and triplet components. The quasi-bound state energy of the system is calculated based on the configuration space Faddeev equations within isospin and averaged potential models. The isospin averaging of $ N{\bar K} $ potentials is used to simplify the isospin model to isospinless one. We show that three-body bound state energy $E_{3}$ has a lower bound within the isospin formalism due to relation $\left\vert E_{3}(V_{NN}=0)\right\vert<2\left\vert E_{2}\right\vert$, where $E_{2}$ is the binding energy of isospin singlet state of the $N{\bar K}$ subsystem. The averaged potential model demonstrates opposite relation between $|E_{2}|$ and $|E_{3}(V_{NN}=0)|$.

• The inversion of the Lorentz integral transform with controlled resolution

  Winfried Leidemann, Victor D. Efros, Veronica Yu. Shalamova

  SciPost Phys. Proc. 3, 037 (2020) · published 26 February 2020 | Toggle abstract · pdf

  The Lorentz integral transform (LIT) method is briefly presented. The ill-posedness of the inversion is discussed and it is pointed out that the LIT is an integral transform with a controlled resolution. As application the dipole response of a three-particle system bound in a hypercentral potential is considered. The inversion is performed in two ways, both employ expansions of the response function and of the LIT on a basis set and a transformed basis set, respectively. A previous study of the process under consideration seemed to point to serious problems in the inversion process. In the present work, however, it is shown that the LIT approach can be carried out in a reliable way.

• How to determine the shape of nuclear molecules with polarized gamma-rays

  Lorenzo Fortunato

  SciPost Phys. Proc. 3, 035 (2020) · published 26 February 2020 | Toggle abstract · pdf

  A method has been recently proposed to establish the geometry of the alpha-cluster arrangement in $^{12}$C making use of polarized gamma-rays. The ratio of intensities of scattered radiation at 90 degrees along and perpendicular to the initial direction of the electric field vector, called depolarization ratio, is a key quantity that allows to underpin the nature of totally symmetric modes of vibrations. This allows to connect with the underlying point-group structure and therefore to the geometric shape of the nuclear molecule. This method is reviewed for $^{12}$C and extended to other configurations, such as three unequal clusters and four identical clusters (e.g. $^{16}$O).

• Response functions and cross sections for inclusive neutrino scattering off $^2$H, $^3$H and $^3$He

  Alessandro Grassi, Jacek Golak, Roman Skibiński, Kacper Topolnicki, Henryk Witała, Hiroyuki Kamada, Laura Elisa Marcucci

  SciPost Phys. Proc. 3, 031 (2020) · published 26 February 2020 | Toggle abstract · pdf

  For several decades there has been an interest in studying neutrino scattering on light nuclei, with the hope of increasing knowledge about the theory of weak interactions and electroweak unification. A study of several neutrino induced reactions on light nuclei ($^2$H, $^3$H and $^3$He) is presented here. The cross section for these reactions is evaluated using the nuclear response functions, which holds the information about the nuclear interactions and structure. This approach has been tested for break-up reactions on the deuteron before and is now extended to three-nucleon break-up reactions.

• Fluctuations of work in realistic equilibrium states of quantum systems with conserved quantities

  Jordi Mur-Petit, Armando Relaño, Rafael A. Molina, Dieter Jaksch

  SciPost Phys. Proc. 3, 024 (2020) · published 25 February 2020 | Toggle abstract · pdf

  The out-of-equilibrium dynamics of quantum systems is one of the most fascinating problems in physics, with outstanding open questions on issues such as relaxation to equilibrium. An area of particular interest concerns few-body systems, where quantum and thermal fluctuations are expected to be especially relevant. In this contribution, we present numerical results demonstrating the impact of conserved quantities (or ‘charges’) in the outcomes of out-of-equilibrium measurements starting from realistic equilibrium states on a few-body system implementing the Dicke model.

• Dipolar condensed atomic mixtures and miscibility under rotation

  Lauro Tomio, R. Kishor Kumar, Arnaldo Gammal

  SciPost Phys. Proc. 3, 023 (2020) · published 25 February 2020 | Toggle abstract · pdf

  By considering symmetric and asymmetric dipolar coupled mixtures (with dysprosium and erbium isotopes), we report a study on relevant anisotropic effects, related to spatial separation and miscibility, due to dipole-dipole interactions (DDIs) in rotating binary dipolar Bose-Einstein condensates. The binary mixtures are kept in strong pancake-like traps, with repulsive two-body interactions modeled by an effective two-dimensional (2D) coupled Gross-Pitaevskii equation. The DDI are tuned from repulsive to attractive by varying the dipole polarization angle. A clear spatial separation is verified in the densities for attractive DDIs, being angular for symmetric mixtures and radial for asymmetric ones. Also relevant is the mass-imbalance sensibility observed by the vortex-patterns in symmetric and asymmetric-dipolar mixtures. In an extension of this study, here we show how the rotational properties and spatial separation of these dipolar mixture are affected by a quartic term added to the harmonic trap of one of the components.

• Influence of the Pauli principle on two-cluster potential energy

  Yuliya A. Lashko, Victor S. Vasilevsky, Gennady F. Filippov

  SciPost Phys. Proc. 3, 021 (2020) · published 25 February 2020 | Toggle abstract · pdf

  We study effects of the Pauli principle on the potential energy of two-cluster systems. The object of the investigation is the lightest nuclei of p-shell with a dominant $\alpha$-cluster channel. For this aim we construct matrix elements of two-cluster potential energy between cluster oscillator functions with and without full antisymmetrization. Eigenvalues and eigenfunctions of the potential energy matrix are studied in detail. Eigenfunctions of the potential energy operator are presented in oscillator, coordinate and momentum spaces. We demonstrate that the Pauli principle affects more strongly the eigenfunctions than the eigenvalues of the matrix and leads to the formation of resonance and trapped states.

• Roy Glauber and asymptotic diffraction theory

  Per Osland

  SciPost Phys. Proc. 3, 016 (2020) · published 25 February 2020 | Toggle abstract · pdf

  This is a review of Glauber's asymptotic diffraction theory, in which diffractive scattering is described in terms of interference between semiclassical amplitudes, resulting from a stationary-phase approximation. Typically two such amplitudes are sufficient to accurately describe elastic scattering, but the stationary points are located at complex values of the impact parameter. Their separation controls the interference pattern, and their offsets from the real axis determine the overall fall-off with momentum transfer. Asymptotically, at large momentum transfers, the stationary points move towards singularities of the profile function. I also include some reminiscences from our collaboration.

• Recent progress on the study of nucleon structure from lattice QCD and future perspectives

  Constantia Alexandrou

  SciPost Phys. Proc. 3, 015 (2020) · published 25 February 2020 | Toggle abstract · pdf

  We review the progress achieved within the last five years in the simulations of lattice QCD, as well as in the analysis for selected quantities probing nucleon structure. In particular, we discuss results on the nucleon electromagnetic form factors, $\sigma$-terms, the momentum fraction carried b quark in the nucleon and the helicity and transversity. All quantities are obtained using simulations generated with quark masses fixed to their physical values. In addition, we review the on-going effort to extract parton distribution functions (PDFs) directly from lattice QCD using the quasi-PDFs approach.

• Investigations of the few-nucleon systems within the LENPIC project

  Jacek Golak, Evgeny Epelbaum, Alessandro Grassi, Hiroyuki Kamada, Hermann Krebs, Patrick Reinert, Roman Skibiński, Volodymyr Soloviov, Kacper Topolnicki, Vitalii Urbanevych, Yuriy Volkotrub, Henryk Witała

  SciPost Phys. Proc. 3, 002 (2020) · published 24 February 2020 | Toggle abstract · pdf

  Results presented in this contribution are obtained within the Low Energy Nuclear Physics International Collaboration (LENPIC). LENPIC aims to develop chiral nucleon-nucleon and many-nucleon interactions complete through at least the fourth order in the chiral expansion. These interactions will be used together with consistently derived current operators to solve the structure and reactions of light and medium-mass nuclei including electroweak processes. In this contribution the current status of the chiral nuclear forces and current operators will be briefly discussed. A special role played by the calculations of nucleon-deuteron scattering will be explained.

  1 citation