Few nucleón dynamics in a nuclear medium

Abstract

Abstract. Few body methods are used in many particle physics to describe correlations, bound states, and reactions in strongly correlated quantum systems. Although this has already been recognized earlier, rigorous attempts to treat three-body collisions have only been done recently. In this talk I shall give examples and areas where few-body methods have been and might be of use in the future.

Medium corrections in the formation of light charged particles in heavy ion reactions

“…That procedure in many cases was very successful. To calculate the rates, including the self energy shift and the proper Pauli blocking, and to study the influence of the medium on different observables, a generalized Alt-Grassberger-Sandhas (AGS) equation [8] has been derived [9][10][11][12][13][14][15]. The effective few-body problem in matter arises within the Green function method [16] when following the cluster mean-field expansion [17] or the Dyson equation approach [18].…”

Three-body problem at finite temperature and density

“…Indeed, the in-matter three-body problem plays an important role in describing a large variety of interesting phenomena in many-body systems. For example, for understanding the formation of bound states in heavy-ion collisions, three-body calculations are needed for studying the modification of the binding energy and wave function of a three-nucleon bound state because of nuclear matter of finite density and temperature [5,6]. Similarly, studies of the binding energy of three quarks are of relevance to the understanding of color superconductivity and phase transitions in quark matter [7,8].…”

“…(48)], the linear approximation cannot be considered as satisfactory for the strong coupling case, e.g., when two-body bound states are possible. The current state-of-the-art formulation [18], which has been used extensively for calculations [5][6][7][8][9][10]18], can be considered as the model of Ref. [17] extended to finite temperatures, with the extension being performed with the imaginary-time formalism of perturbation theory [16].…”

“…[27], contain a blocking factor (n or n) for each fermion line, in contrast to the approach of Refs. [5][6][7][8][9][10] where such factors appear only on non-spectator fermions.…”

Few-body correlations in the QCD phase diagram

“…This has been achieved in the past for the nonrelativistic problem [2,9,10,11]. These equations have been derived on the basis of statistical Green functions [8].…”