Ab initio calculations for non-strange and strange few-baryon systems

Winfried Leidemann

doi:10.1088/1742-6596/981/1/012018

Abstract

Concerning the non-strange particle systems the low-energy excitation spectra of the three- and four-body helium isotopes are studied. Objects of the study are the astrophysical S-factor S12 of the radiative proton deuteron capture d(p, )3He and the width of the 4He isoscalar monopole resonance. Both observables are calculated using the Lorentz integral transform (LIT) method. The LIT equations are solved via expansions of the LIT states on a specifically modified hyperspherical harmonics (HH) basis. It is illustrated that at low energies such a modification allows to work with much higher LIT resolutions than with an unmodified HH basis. It is discussed that this opens up the possibility to determine astrophysical S-factors as well as the width of low-lying resonances with the LIT method. In the sector of strange baryon systems binding energies of the hypernucleus H are calculated using a nonsymmetrized HH basis. The results are compared with those calculated by various other groups with different methods. For all the considered non-strange and strange baryon systems it is shown that high-precision results are obtained.

Highlights

Non-strange and strange few-baryon systems are interesting particle systems in the hadronic sector
Method for a precise determination of specific details in nuclear low-energy cross sections that are induced by external electromagnetic probes
The 3He photodisintegration has been calculated in order to obtain the astrophysical S-factor S12 of its inverse reaction, i.e. d(p, γ)3He, by applying time reversal invariance

Summary

Introduction

Non-strange and strange few-baryon systems are interesting particle systems in the hadronic sector. Since in the present work it is the aim to test the precision of various theoretical ab initio approaches we do not employ realistic interaction models, but use instead simpler potential models, which will be defined . 2. The LIT method Nuclear cross sections of inclusive reactions with electromagnetic probes are expressed in terms of inclusive response functions, which contain the information about the dynamics of the nucleus under investigation. In the LIT applications of the present work a new basis Φ[K]nn l is employed in addition It consists of a separation of the A-body basis in a (A − 1)-part with HH basis functions. For Rn(2)(rA) a similar expansion as for the hyperradial part is taken, namely a Laguerre polynomial L(n2)(rA) times an exponential factor exp(−rA/2bA) In this case one may use the NN correlation functions, discussed above, in addition. As for the HH basis given in eq (7), one has to multiply the basis functions of eq (8) with appropriate A-body spin-isospin wave functions and one has to care for an antisymmetric state by making a proper antisymmetrization of the basis states

MeV 20 MeV

Summary