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Nuclear Theory·nucl-th

Thursday·May 16, 2019

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 06

    Roles of crust and core in the tidal deformability of neutron stars

    A. M. Kalaitzis🇦🇺 · T. F. Motta🇦🇺 · A. W. Thomas🇦🇺

    With the recent measurement of GW170817 providing constraints on the tidal deformability of a neutron star, it is very important to understand what features of the equation of state have the biggest effect on it. We therefore study the contribution of the crust to the tidal deformability and the moment of inertia of a neutron star for a variety of well-known equations of state. It is found that the contributions to these quantities from the low density crust are typically quite small and as a result the determination of the tidal deformability provides an important constraint on the equation of state of dense matter.

    ↳ astro-ph.HEnucl-thIJMPE(2019)·13 citations
  2. 07

    Aspects of the QCD -vacuum

    Thomas Vonk🇩🇪 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪

    This paper addresses two aspects concerning the -vacuum of Quantum Chromodynamics. First, large- chiral perturbation theory is used to calculate the first two non-trivial cumulants of the distribution of the winding number, i.\,e. the topological susceptibility, , and the fourth cumulant, , up to next-to-leading order. Their large- scaling is discussed, and compared to lattice results. It is found that , as known before, and , correcting the assumption of in the literature. Second, we discuss the properties of QCD at using chiral perturbation theory for the case of light flavors, i.\,e. by taking the strange quark mass heavier than the degenerate up and down quark masses. It is shown that --- in accordance with previous findings for and mass-degenerate flavors --- in the region two vacuum states coexist, which become degenerate at . The wall tension of the energy barrier between these degenerate vacua is determined as well as the decay rate of a false vacuum.

    ↳ hep-thhep-lathep-phnucl-thJHEP(2019)·15 citations
  3. 08

    Energy of the Th nuclear clock transition

    Benedict Seiferle · Lars von der Wense · Pavlo V. Bilous · Ines Amersdorffer · Christoph Lemell · Florian Libisch · Simon Stellmer · Thorsten Schumm · Christoph E. Düllmann · Adriana Pálffy · Peter G. Thirolf

    The first nuclear excited state of Th offers the unique opportunity for laser-based optical control of a nucleus. Its exceptional properties allow for the development of a nuclear optical clock which offers a complementary technology and is expected to outperform current electronic-shell based atomic clocks. The development of a nuclear clock was so far impeded by an imprecise knowledge of the energy of the Th nuclear excited state. In this letter we report a direct excitation energy measurement of this elusive state and constrain this to 8.280.17 eV. The energy is determined by spectroscopy of the internal conversion electrons emitted in-flight during the decay of the excited nucleus in neutral Th atoms. The nuclear excitation energy is measured via the valence electronic shell, thereby merging the fields of nuclear- and atomic physics to advance precision metrology. The transition energy between ground and excited state corresponds to a wavelength of 149.73.1 nm. These findings set the starting point for high-resolution nuclear laser spectroscopy and thus the development of a nuclear optical clock of unprecedented accuracy. A nuclear clock is expected to have a large variety of applications, ranging from relativistic geodesy over dark matter research to the observation of potential temporal variation of fundamental constants.

    ↳ nucl-exnucl-thphysics.ins-detNature(2019)·152 citations

Affiliations

first authorsco-authorsvia INSPIRE