Few-Body Systems最新文献

We show that the N(1440) Roper resonance naturally appears in the nuclear model with explicit mesons as a structure in the continuum spectrum of the physical proton, which in this calculation is made of a bare nucleon dressed with a pion cloud.

Abstract

Characteristics of the quasi-bound state in the (K^- pp) system strongly depend on the model of antikaon–nucleon interaction and weakly—on the nucleon–nucleon potential. In the present paper, dynamically exact Faddeev-type calculations with coupled (bar{K}NN) and (pi varSigma N) were performed using different models of the (varSigma N) and (pi N) interactions to study the influence of these “less important” interactions on the three-body result. In addition, dynamically exact three-body Faddeev-type AGS calculations with three coupled particle channels (bar{K}NN - pi varSigma N - pi varLambda N) were performed.

We propose a computational method for relativistic spin-1/2 particles by solving the corresponding Feshbach–Villars equation. We have found that the Feshbach–Villars spin-1/2 Hamiltonian can be written as two spin-coupled Feshbach–Villars spin-0 Hamiltonians. For the solution method, we adopted an integral equation formalism. The potential operators are represented in a discrete Hilbert space basis and the relevant Green’s operator has been calculated by a matrix continued fraction.

We investigate the spin entanglement in few-nucleon scattering processes involving nucleons and deuterons. For this purpose, we consider the entanglement power introduced by Beane et al. We analyze different entanglement entropies as a basis to define the entanglement power of the strong interaction and calculate the corresponding entanglement powers for proton–neutron, neutron–deuteron, proton–deuteron, and deuteron–deuteron scattering. For the latter two processes, we also take into account the modification from the Coulomb interaction. In contrast to proton–neutron scattering, no universal low-energy features are evident in the spin entanglement in neutron–deuteron, proton–deuteron, and deuteron–deuteron scattering.

We present the measured spin correlation coefficient (C_{y,y}) for p-(^3)He elastic scattering at 100 MeV at the angles (theta _mathrm{c.m.}=46.9^circ )–(149.2^circ ) in the center of mass system. The experiment was performed using a 100 MeV polarized proton beam in conjunction with the polarized (^3)He target. Proton beams were injected to the target, and scattered protons were detected by using E-(Delta E) detectors which consisted of plastic and NaI(Tl) scintillators. The data are compared with rigorous numerical calculations based on realistic NN potentials as well as with the (Delta )-isobar excitation . The obtained results indicate that the (C_{y,y}) expands the knowledge of the nuclear interactions with (Delta )-isobar or those including 3NFs that are masked in nucleon-deuteron elastic scattering.

Abstract

We explore the effect of a finite two-body energy in the discrete scale symmetry regime of two heavy bosonic impurities immersed in a light bosonic system. By means of the Born–Oppenheimer approximation in non-integer dimensions (D), we discuss the effective potential of the heavy-particles Schrodinger equation. We study how including the two-body energy in the effective potential changes the light-particles wave function and the ratio between successive Efimov states. We present the limit cycles associated with correlation between the energy of successive levels for the three and four-body systems. Our study is exemplified by considering a system composed of N-bosons, namely two Rubidium atoms interacting with N-2 Lithium ones ( (^7) Li (_{N-2}{-}^{87}) Rb (_2) ), which represent compounds of current experimental interest.

According to the rainbow formalism of general relativity, as a particle engages with space-time through its movement, it alters the fabric of space-time, and this manifests itself in rainbow functions. Therefore, the dynamics of the particle necessitate a redefinition within the newly textured space-time. In this context, an exact solution to the Dirac equation has been investigated to determine the dynamics of Dirac particles within the (2+1)-dimensional rotating symmetric rainbow universe in the present study. So, the equation representing the energy eigenvalues of Dirac particles and the corresponding eigenfunctions in terms of the associated Laguerre polynomials have been derived. Notably, it has been observed that the energies and corresponding eigenfunctions of spin-1/2 fermions change dramatically due to rainbow functions. The energy eigenvalue equation has been reformulated within the general relativity limit of the rainbow formalism, and the energy eigenvalue equation representing massless Dirac particles has been obtained in this limit.

By replacing the spatial derivative with the Dunkl derivative, we generalize the Fokker-Planck equation in (1+1) dimensions. We obtain the Dunkl–Fokker–Planck eigenvalues equation and solve it for the harmonic oscillator plus a centrifugal-type potential. Furthermore, when the drift function is odd, we reduce our results to those of the recently developed Wigner–Dunkl supersymmetry.

The correlation function is a useful tool to study the interaction between hadrons. The theoretical description of this observable requires the knowledge of the scattering wave function, whose asymptotic part is distorted when two or more particles are charged. For a system of three (or more) particles, with more than two particles asymptotically free and at least two of them charged, the asymptotic part of the wave function is not known in a closed form. In the present study we introduce a screened Coulomb potential and analyze the impact of the screening radius on the correlation function. As we will show, when a sufficiently large screening radius is used, the correlation function results almost unchanged if compared to the case in which the unscreened Coulomb potential is used. This fact allows the use of free asymptotic matching conditions in the solution of the scattering equation simplifying noticeably the calculation of the correlation function. As an illustration we discuss the pp and ppp correlation functions.

Differential cross section for the (^1)H(d,pp)n deuteron breakup reaction is sensitive to dynamical ingredients such as three-nucleon force or Coulomb force and allows for thorough tests of theoretical potential models describing the interaction in the three nucleon systems. The analysis of the experimental data collected for the breakup reaction at the beam energy of 100 MeV has been performed and the cross section results for selected configurations are presented. They are in good agreement with calculations based on the realistic potentials and state-of-the-art calculations within the Chiral Effective Field Theory framework.