Phenomenology of the deuteron electromagnetic form factors

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm⁻¹. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data. Received: 28 January 2000 / Revised version: 25 February 2000     

Deuteron under strong magnetic fields: Skyrme model study

We explore the deuteron under strong magnetic fields in Skyrme models. The effects of the derivative dependent sextic term in the Skyrme Lagrangian are investigated, and the rational map approximation is used to describe the deuteron. The influences of strong magnetic fields on the electric charge distribution and mass of the deuteron are discussed.     

Polarization effects in elastic electron deuteron scattering

The vector and tensor polarization of the deuteron after scattering and the dependence of the cross section on the polarization before scattering are given for elastic electron deuteron scattering treating the deuteron as a spin 1 elementary particle characterized by three electromagnetic formfactors and describing the interaction by the first Born approximation. By using polarization measurements a separation of the charge and quadrupole formfactors may be accomplished, and thus the assumptions may be tested, which are necessary for the extraction of the isoscalar nucleon formfactors from the deuteron formfactors.     

A Discussion of Deuteron Transverse Charge Densities

The deuteron transverse charge density ρ_C(b) is the two-dimensional Fourier transform of its charge form factor in the impact space. We show that different parameterizations of the charge form factors provide different ρ_C(b), in particular at the central value of impact parameter (b=0), although all the parameterizations can well reproduce the form factors in the region of small Q². In addition, we also check the explicit contributions from the different coordinate intervals of the deuteron wave function to its root-mean-square radius.     

Charge form factor and cluster structure of the 6Li nucleus

The charge form factor of the 6Li nucleus is considered on the basis of its cluster structure. The charge density of ⁶Li is presented as a superposition of two terms. One of them is a folded density and the second one is a sum of the ⁴He and deuteron densities. Using the available experimental data for ⁴He and deuteron charge form factors, a satisfactory agreement of the calculations within the suggested scheme is obtained with the experimental data for the charge form factor of ⁶Li, including those in the region of large transferred momenta.      

The folding deuteron optical model potentials

In this paper we construct a kind of deuteron optical potential with the folding model. For the nucleon optical potential, we choose two kinds of forms: the phenomenological global nucleon optical potential and the microscopic nucleon optical potential based on the nuclear-matter approach. We use our folding and global deuteron optical potential to calculate the reaction cross-sections, elastic scattering angular distributions, and the values for 64 target nuclei.     

Deuteron electromagnetic form factors with the light-front approach

The electromagnetic form factors and low-energy observables of the deuteron are studied with the help of the light-front approach, where the deuteron is regarded as a weakly bound state of a proton and a neutron. Both the S and D wave interacting vertexes among the deuteron, proton, and neutron are taken into account. Moreover,the regularization functions are also introduced. In our calculations, the vertex and the regularization functions are employed to simulate the momentum distribution inside the deuteron. Our numerical results show that the lightfront approach can roughly reproduce the deuteron electromagnetic form factors, like charge G_0, magnetic G_1, and quadrupole G_2, in the low Q~2 region. The important effect of the D wave vertex on G_2 is also addressed.     

Correlations of two protons in relativisticdp-collisions

Two-proton correlations in thedpppn collisions of relativistic deuterons with protons are considered. These correlations give more information than inclusive proton spectra described in the framework of different deuteron structure function models because of uncertainty in the calculation of secondary interaction contribution (rescattering processes and final state interactions). We present the predictable calculations which show different behaviour of the correlation function for different deuteron structure function models in the kinematic region where contributions of secondary interactions are negligible.     

Measurement of tensor polarization in elastic electron-deuteron scattering at large momentum transfer

Tensor polarization observables ( t(20), t(21), and t(22)) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c)(2). The experiment was performed at the Jefferson Laboratory in Hall C using the electron High Momentum Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q2 the deuteron charge form factors G(C) and G(Q). They are in good agreement with relativistic calculations and disagree with perturbative QCD predictions.     

Elastic electron deuteron scattering

Measurements of the ratio of the deuteron to proton electric form factors were made for low q. The rms radius of the deuteron structure factor was found to be 1.9635 ± 0.0045 fm, yielding an rms charge radius of 2.095 ± 0.006 fm.     

On the six-quark structure in the deuteron form factor

The charge and quadrupole deuteron form factors are investigated in a wide region of momentum transfer taking into account the deuteron six quark structure. It is shown that the contribution due to the antisymmetrization of the wave function with respect to quark variables is small and the contribution of the “true” six quark admixtures plays the leading role in the region of large momentum transfer.     

Intense deuteron beam investigation by activation yield-ratio technique

In this work, the intense deuteron beam from a plasma focus device is investigated by the activation yield-ratio technique. It is shown that boron-carbide (B₄C) and boron-nitride (BN) are complimentary targets for high energy deuteron beam studies. For deuteron spectra of the form dNd/dE∝E−n, when deuteron spectra decrease relatively gradually (n<6) BN is a better choice, while for the case of very rapidly decreasing deuteron spectra (n>6), B₄C is more suitable.     

Nucleon charge exchange on the deuteron: A critical review

The existing experimental data on the d(n, p)nn and d(p, n)pp cross-sections in the forward direction are reviewed in terms of the Dean sum rule. It is shown that the measurement of the ratio of the charge exchange on the deuteron to that on the proton might, if taken together with other experimental data, allow a direct construction of the np → np scattering amplitude in the backward direction with few ambiguities. Communicated by T. Hennino     

The charge exchange reaction dp → (pp)n

The ratio of the differential cross section of the charge exchange reaction of the deuteron to that of the nucleon, at small transferred momenta, has been discussed in order to estimate the spin-dependent part of the np → pn charge exchange amplitude.      

Fast deuteron production in proton-nucleus interactions

Deuteron formation in proton-nucleus reactions due to the coalescence mechanism with final-state interaction between nucleons is discussed in order to establish the kinematical region of the validity of this approach. The experimental data on fast deuteron production in proton-nucleus collisions at bombarding energies above 3 GeV are analyzed. It is shown that most experimental results were obtained for deuteron momenta below the critical limit of the coalescence model. It is discussed to which extent further experimental studies could help to identify contributions from the coalescence mechanism and to get better understanding of the fast deuteron-production process.This article was processed by the author using the LATEX style filepljour2 from Springer-Verlag.     

Possible interpretation of the „anomalous“ behaviour of the proton spectrum at 0° from the deuteron fragmentation at 9 GeV/c

The momentum spectra of protons, produced at 0° as a result of fragmentation of relativistic deuterons on nuclei, are analyzed. Possible causes of the existing discrepancy of the data on the 0° proton spectrum from the¹ H(d,p)X reaction at 9.1 GeV/c with results of the impulse approximation calculations are considered. It is shown that taking into account the finite angular resolution of the experimental setup and the corresponding renormalization of the experimental data, on the one hand, and also the inclusion of the additional (to stripping) contribution of protons from the scattering of deuteron nucleons by target protons, on the other, make it possible to match these data with the results of calculations within the framework of the relativistic impulse approximation using the deuteron wave function for the Paris potential.     

Form factors and polarization in the elasticeD-scattering with inclusion of meson and quark degrees of freedom in a deuteron

A detailed analysis is made of the pair,ρπγ-currents, retardation effects and six-quark admixtures to the charge, quadrupole form factors and to the deuteron polarization. It is shown that the elasticeD-scattering cross section allowing for the meson exchange currents can be described by introducing a six-quark admixture with probability 3.5%. It is predicted that the behaviour of the deuteron polarization tensor at q>4 fm^?1 essentially depends on 6q-admixture.