On the role of theΔ -isobar in deep inelastic scattering on the deuteron

The role of the nuclear structure effects, viz. the boundness of nucleons and-isobar components, in the deep inelastic scattering of leptons on the deuteron is considered. It is shown that small admixture of the-isobar configurations to the deuteron wave function may lead to significant effects in the spin structure functions of the deuteronb ₁ ^D andg ₁ ^D (x): up to 4% in g ₁ ^D (x) dx and up to 10% ing ₁ ^D (x) at smallx.One of the authors (A.U.) thanks Prof. F.C. Khanna for helpful discussions and for kind offering the information used in our calculations.     

Solving the Dyson–Schwinger Equation at Zero and Finite Temperatures

The properties of the solutions of the truncated Dyson–Schwinger equation for the quark propagator at finite temperatures within the rainbow-ladder approximation are analysed in some detail.     

Interpretation of the processes 3He(e,e'p)2H and 3He(e,e'p)(pn) at high missing momenta

Using realistic three-body wave functions corresponding to the AV18 interaction, it is shown that the effects of the final state interaction in the exclusive processes 3He(e,e'p)2H and 3He(e,e'p)(pn), can be successfully treated in terms of a generalized eikonal approximation based upon the direct calculation of the Feynman diagrams describing the rescattering of the struck nucleon. The relevant role played by the double rescattering contribution at high values of the missing momentum is illustrated.     

Exclusive charge exchange reaction pD↦n(pp) within the Bethe-Salpeter formalism

The exclusive charge exchange reaction pD↦n(pp) at intermediate and high energies is studied within the Bethe-Salpeter formalism. The final-state interaction in the detected pp pair at nearly zero excitation energy is described by the ¹ S ₀ component of the Bethe-Salpeter amplitude. Results of numerical calculations of polarization observables and differential cross-section persuade that, as in the non-relativistic case, this reaction i) can be utilized as a “relativistic deuteron polarimeter” and ii) delivers further information about the elementary nucleon-nucleon charge exchange amplitude. Received: 26 November 2002 / Accepted: 30 January 2003 / Published online: 29 April 2003     

Two-fermion bound states within the Bethe-Salpeter approach

To solve the spinor-spinor Bethe-Salpeter equation in Euclidean space we propose a novel method related to the use of hyperspherical harmonics. We suggest an appropriate extension to form a new basis of spin-angular harmonics that is suitable for a representation of the vertex functions. We present a numerical algorithm to solve the Bethe-Salpeter equation and investigate in detail the properties of the solution for the scalar, pseudoscalar and vector meson exchange kernels including the stability of bound states. We also compare our results to the nonrelativistic ones and to the results given by light-front dynamics.     

Final-state interaction effects in semi-exclusive DIS off the deuteron

The effects of the final-state interaction (FSI) in semi-exclusive deep inelastic scattering of electrons off the deuteron are analyzed paying particular attention to two extreme kinematical regions: i) the one where FSI effects are minimized, so that the quark distribution of bound nucleons could be investigated, and ii) the one where the re-interaction of the produced hadrons with the spectator nucleon is maximized, which would allow one to study the mechanism of hadronization of highly virtual quarks. It is demonstrated that when the recoiling spectator nucleon is detected in the backward hemisphere with low momentum, the effects from the FSI are negligible, whereas at large transverse momenta of the spectator, FSI effects are rather large. Numerical estimates show that the FSI corrections are sensitive to the theoretical models of the hadronization mechanism.Received: 14 July 2003, Published online: 18 December 2003PACS: 24.85. + p Quarks, gluons, and QCD in nuclei and nuclear processes - 25.10. + s Nuclear reactions involving few-nucleon systems - 25.30.Fj Inelastic electron scattering to continuumL.P. Kaptari: On leave from the Bogoliubov Laboratory of Theoretical Physics, 141980, JINR, Dubna, Russia.B.Z. Kopeliovich: Also at Dzhelepov Laboratory of Nuclear Problems, 141980, JINR, Dubna, Russia.     

Ghost and Gluon Propagators at Finite Temperatures within a Rainbow Truncation of Dyson–Schwinger Equations

JETP Letters - The finite-temperature behavior of ghost and gluon propagators is investigated within an approach based on the rainbow truncated Dyson–Schwinger equations in Landau gauge. In...     

Polarization observables in the reaction pn↦dφ

The reaction pn↦dφ is studied within a covariant boson exchange model. The behavior of polarization observables being accessible in forthcoming experiments near threshold is predicted. Received: 13 February 2001 / Accepted: 25 March 2002     

Nonfactorized calculation of the process 3He(e,e'p)(2H) at medium energies

The exclusive process 3He(e,e'p)(2H) has been analyzed by a nonfactorized and parameter-free approach based upon realistic few-body wave functions corresponding to the AV18 interaction and treating the rescattering of the struck nucleon within a generalized eikonal approximation. The results of our calculations, compared with recent JLab experimental data, show that the left-right asymmetry exhibits a clear dependence upon the final state interaction demonstrating the breaking down of the factorization approximation at "negative" and large ( greater, similar300 MeV/c) values of the missing momentum.