Amand Faessler

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During the last decade, the problem of the description of hadrons in dense and hot nuclear matter received great attention. The purpose of the current investigations is to determine experimentally mass shifts and the broadening of hadronic resonances at finite density and temperature. The dilepton spectra from heavy-ion collisions are a suitable tool for(More)
A new scheme for testing nuclear matter equations of state (EoSs) at high densities using constraints from neutron star (NS) phenomenology and a flow data analysis of heavy-ion collisions is suggested. An acceptable EoS shall not allow the direct Urca process to occur in NSs with masses below 1.5M , and also shall not contradict flow and kaon production(More)
We calculate the electromagnetic moments and radii of the ∆(1232) in the nonrel-ativistic quark model, including two-body exchange currents. We show that two-body exchange currents lead to nonvanishing ∆ and N → ∆ transition quadrupole moments even if the wave functions have no D-state admixture. The usual explanation based on the single-quark transition(More)
We show that, within the quasiparticle random phase approximation (QRPA) and the renormalized QRPA (RQRPA) based on the Bonn-CD nucleon-nucleon interaction, the competition between the pairing and the neutron-proton particle-particle and particle-hole interactions causes contributions to the neutrinoless double-beta decay matrix element to nearly vanish at(More)
We discuss the dressing of constituent quarks with a pseudoscalar meson cloud within the effective chiral quark model. SU (3) f symmetry breaking effects are included explicitly. Our results are compared with those of the traditional meson cloud approach in which pions are coupled to the nucleon. The pionic dressing of the constituent quarks explains the(More)
We apply the perturbative chiral quark model at one loop to analyze the electromagnetic form factors of the baryon octet. The analytic expressions for baryon form factors, which are given in terms of fundamental parameters of low-energy pion-nucleon physics(weak pion decay constant, axial nucleon coupling, strong pion-nucleon form factor), and the numerical(More)
We study the semileptonic decays of the lowest lying double heavy baryons using the relativistic three-quark model. We do not employ a heavy quark mass expansion but keep the masses of the heavy quarks and baryons finite. We calculate all relevant form factors and decay rates. The semileptonic decays of heavy mesons and baryons are ideally suited to extract(More)