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Nuclear Theory·nucl-th

Tuesday·July 18, 2017

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 04

    Chiral symmetry and the properties of hadrons in the Generalised Nambu-Jona-Lasinio model

    Yu.S. Kalashnikova🇷🇺 · A.V. Nefediev🇷🇺 · J.E.F.T. Ribeiro🇵🇹

    Various aspects of the Generalised Nambu-Jona-Lasinio model for QCD in four dimensions are reviewed. The properties of mesonic excitations are discussed in detail, with special attention paid to the chiral pion. The spontaneous chiral symmetry breaking in the vacuum and the effective chiral symmetry restoration in the spectrum of highly excited mesons and baryons are described microscopically.

    ↳ hep-phhep-lathep-thnucl-thPhys.Usp.(2017)·6 citations
  2. 05

    From hadrons to quarks in neutron stars: a review

    Gordon Baym🇯🇵 · Tetsuo Hatsuda🇯🇵 · Toru Kojo🇺🇸 · Philip D. Powell🇺🇸 · Yifan Song🇺🇸 · Tatsuyuki Takatsuka🇯🇵

    We review the equation of state of matter in neutron stars from the solid crust through the liquid nuclear matter interior to the quark regime at higher densities. We focus in detail on the question of how quark matter appears in neutron stars, and how it affects the equation of state. After discussing the crust and liquid nuclear matter in the core we briefly review aspects of microscopic quark physics relevant to neutron stars, and quark models of dense matter based on the Nambu--Jona-Lasinio framework, in which gluonic processes are replaced by effective quark interactions. We turn then to describing equations of state useful for interpretation of both electromagnetic and gravitational observations, reviewing the emerging picture of hadron-quark continuity in which hadronic matter turns relatively smoothly, with at most only a weak first order transition, into quark matter with increasing density. We review construction of unified equations of state that interpolate between the reasonably well understood nuclear matter regime at low densities and the quark matter regime at higher densities. The utility of such interpolations is driven by the present inability to calculate the dense matter equation of state in QCD from first principles. As we review, the parameters of effective quark models -- which have direct relevance to the more general structure of the QCD phase diagram of dense and hot matter -- are constrained by neutron star mass and radii measurements, in particular favoring large repulsive density-density and attractive diquark pairing interactions. We describe the structure of neutron stars constructed from the unified equations of states with crossover. Lastly we present the current equations of state -- called "QHC18" for quark-hadron crossover -- in a parametrized form practical for neutron star modeling.

    ↳ astro-ph.HEhep-phnucl-exnucl-thRept.Prog.Phys.(2018)·957 citations
  3. 06

    Dihadron fragmentation functions in the quark-jet model: Longitudinally polarized quarks

    Hrayr H. Matevosyan🇦🇺 · Aram Kotzinian🇮🇹 · Anthony W. Thomas🇦🇺

    We study the dihadron fragmentation functions (DiFF) of longitudinally polarized quarks into pion pairs. The quark-jet framework is used to model the sequential hadronization of a polarized quark into hadrons, where the polarization transfer to the remnant quark in each hadron emission step is calculated using the spin density matrix formalism. Using Monte Carlo (MC) simulations of the hadronization process, we find a nonvanishing helicity dependent DiFF, , which is also related to the longitudinal jet handedness. A method is developed for extracting the angular moments of this DiFF, which enter the expressions for the azimuthal asymmetries for an electron-positron annihilation process into two pairs of hadrons from back-to-back jets and the dihadron production in semi-inclusive deep inelastic scattering. Finally, we derive explicit integral expressions for DiFFs where only two hadrons are emitted by a quark and use them to validate our MC results for both unpolarized and helicity dependent DiFFs.

    ↳ hep-phnucl-thPRD(2017)·23 citations
  4. 07

    Drag Force on Heavy Quarks and Spatial String Tension

    Oleg Andreev🇷🇺

    Heavy quark transport coefficients in a strongly coupled Quark-Gluon Plasma can be evaluated using a gauge/string duality and lattice QCD. Via this duality, one can argue that for low momenta the drag coefficient for heavy quarks is proportional to the spatial string tension. Such a tension is well studied on the lattice that allows one to straightforwardly make non-perturbative estimates of the heavy quark diffusion coefficients near the critical point. The obtained results are consistent with those in the literature.

    ↳ hep-phhep-lathep-thnucl-thMod.Phys.Lett.A(2018)·29 citations
  5. 08

    Parity doubling of baryons in a chiral approach with three flavors

    Chihiro Sasaki🇵🇱

    We formulate a set of mass relations for the baryon octet and decuplet with positive and negative parity in terms of the order parameter of QCD chiral symmetry. The Gell-Mann--Okubo mass formula and Gell-Mann's equal spacing rule hold manifestly in this approach. Thermal masses of the baryons are calculated in the mean field approximation for various pion masses, and the results are compared with the recent lattice studies. A general trend of the nucleon, and parity-doublers seen in the available lattice data can be understood qualitatively. Expected mass modifications of other strange baryons are also given with the physical and heavier pion masses.

    ↳ hep-phnucl-thNPA(2018)·28 citations
  6. 09

    Strange Hadron Spectroscopy with a Secondary KL Beam at GlueX

    M.J. Amaryan (ODU) · M. Bashkanov (Edinburgh U.) · J. Ritman (Ruhr-U.) · J.R. Stevens (W&M) · I. Strakovsky (GWU) · GlueX Collaboration

    We propose to create a secondary beam of neutral kaons in Hall D at Jefferson Lab to be used with the GlueX experimental setup for strange hadron spectroscopy. A flux on the order of 3 x 10^4 KL/s will allow a broad range of measurements to be made by improving the statistics of previous data obtained on hydrogen targets by three orders of magnitude. Use of a deuteron target will provide first measurements on the neutron which is {\it terra incognita}. The experiment will measure both differential cross sections and self-analyzed polarizations of the produced {\Lambda}, {\Sigma}, {\Xi}, and {\Omega} hyperons using the GlueX detector at the Jefferson Lab Hall D. The measurements will span c.m. cos{\theta} from -0.95 to 0.95 in the c.m. range above W = 1490 MeV and up to 3500 MeV. These new GlueX data will greatly constrain partial-wave analyses and reduce model-dependent uncertainties in the extraction of strange resonance properties (including pole positions), and provide a new benchmark for comparisons with QCD-inspired models and lattice QCD calculations. The proposed facility will also have an impact in the strange meson sector by providing measurements of the final-state K{\pi} system from threshold up to 2 GeV invariant mass to establish and improve on the pole positions and widths of all K*(K{\pi}) P-wave states as well as for the S-wave scalar meson {\kappa}(800).

    ↳ hep-exhep-phnucl-exnucl-th18 citations

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first authorsco-authorsvia INSPIRE