Using the QCD sum rules we calculate the neutron-proton mass difference at zero density as a function of the difference in bare quark mass m a m u. We confirm results of Hatsuda, Hogaasen and Prakash that the largest term results from the difference in up and down quark condensates, the explicit ~ (m a m, ) entering with the opposite sign. The quark condensates are then extended to finite densi...

We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal spin-exchange-polarized 3He cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable 3He polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation o...

We propose an experiment to isotopically identify and determine the production cross sections of residual nuclei in the fragmentation of very neutron-rich nuclei around Sn produced in the fission of relativistic U primary projectiles. These measurements will provide valuable information about a possible two-step reaction scheme (fission-fragmentation) to optimise the production of extremely neu...

The application of IR spectroscopy to the characterization and quality control of samples used in neutron crystallography is described. While neutron crystallography is a growing field, the limited availability of neutron beamtime means that there may be a delay between crystallogenesis and data collection. Since essentially all neutron crystallographic work is carried out using D2O-based solve...

We study the ‘minimal’ cooling scenario of superfluid neutron stars with nucleon cores, where the direct Urca process is forbidden and enhanced cooling is produced by neutrino emission due to the Cooper pairing of neutrons. Extending our recent previous work, we include the effects of surface accreted envelopes of light elements. We employ the phenomenological density-dependent critical tempera...

First results from a fully self-consistent, temperature-dependent equation of state that spans the whole density range of neutron stars and supernova cores are presented. The equation of state (EoS) is calculated using a mean-field Hartree-Fock method in three dimensions (3D). The nuclear interaction is represented by the phenomenological Skyrmemodel in this work, but the EoS can be obtained in...

Strange stars that are entirely made of strange quark matter (SQM) have been long ago proposed as an alternative to neutron stars (e.g., [1, 2]). The possible existence of strange stars is a direct consequence of the conjecture that SQM composed of roughly equal numbers of up, down, and strange quarks plus a smaller numbers of electrons (to neutralize the electric charge of the quarks) may be t...

The temperature dependence of H-U(iso) in N-acetyl-L-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U(iso) below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffract...

Karl-Ludwig Kratz Universität Mainz Email: [email protected] An interesting question in nuclear astrophysics is the fate of post X-ray burst matter. Once an accreting neutron star has undergone thermonuclear runaway, the ashes of the burst are forced down into the crust of the neutron star. With increasing density a volume element of matter undergoes a number of electron captures and neutron...

Recently, neutron stars with very strong surface magnetic fields have been suggested as the site for the origin of observed soft gamma repeaters (SGRs). In this paper we investigate the influence of such strong magnetic fields on the properties and internal structure of these magnetized neutron stars (magnetars). We study properties of a degenerate equilibrium ideal neutron-proton-electron (npe...