Neutron Stars

Abstract

The role of nuclear physics is outlined for the properties of neutron stars. The outer crust of a neutron star consists of a lattice of neutron‐rich nuclei immersed in a sea of electrons, which extends up to the neutron dripline. Beyond the neutron‐drip density, a neutron superfluid forms within a lattice of nuclei, which can build up geometric phases, the nuclear pasta of the crust. The equation of state of the outer core of a neutron star, which consists of neutrons, protons, and leptons only, can be constrained by modern calculations of pure neutron matter. The inner core of a neutron star can harbor exotic dense‐matter phases with strangeness, which can be explored by studying massive pulsars. There emerges a growing interplay of the observations of neutron star properties with the study of the nuclear equation of state and the quantum chromodynamics ( QCD )‐ phase diagram by relativistic heavy‐ion collisions.

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

“…If strange quark matter is absolutely stable, it can form selfbound stars completely made of strange quark matter only covered by a thin hadronic or strangelet crust. The first pure quark star was calculated by Itoh (1970) followed up today by a large sample of approaches for quark matter (for an overview see Schaffner-Bielich 2007Weber 2005). Up to now, quark stars cannot be excluded by observation, because they are even compatible with pulsar masses up to two solar masses, as pointed out by Alford et al (2007).…”

Production of ΛΛ and Λn¯ in central Pb + Pb collisions at sSun1, Chen2 2016Phys. Rev. C11060View full textAdd to dashboardCite

“…Shown in Fig. 3 is the comparison of the yields (dN /dy at y = 0) of Λn (panel (a)) and ΛΛ (panel (b)) verse decay length (lifetime) between experimental upper-limits and theoretical calculations, and here a preferred branching ratio of 64% [41] is used for ΛΛ → Λpπ − and 54% [42] for Λn →dπ + . It is very interesting to see that while the predicted yield of Λn in either molecular state or six-quark state is higher than the experimental upper-limit, the yield of six-quark-state ΛΛ could be lower than the experimental upper-limit although the yield of molecule-state ΛΛ is higher than the upper-limit.…”

Exotica production with ALICE

“…We focus here on the Λn, since the background is much lower compared to Λn. The expected signal was computed estimating the acceptance × efficiency (from a Monte Carlo simulation), the production rates as predicted by the thermal-model [14] and the expected branching ratios [12,15]. For the Monte Carlo simulation, involving full decay kinematics and transport in the material utilizing GEANT3, the lifetime of the free Λ hyperon was assumed for both exotic states.…”