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Nuclear Theory·nucl-th

Monday·October 26, 2015

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    [Submitted on 23 Oct 2015]

    Testing the importance of collective correlations in neutrinoless decay

    J. Menéndez🇩🇪 · N. Hinohara🇺🇸 · J. Engel🇺🇸 · G. Martínez-Pinedo🇩🇪 · T. R. Rodríguez🇪🇸

    We investigate the extent to which theories of collective motion can capture the physics that determines the nuclear matrix elements governing neutrinoless double-beta decay. To that end we calculate the matrix elements for a series of isotopes in the full shell, omitting no spin-orbit partners. With the inclusion of isoscalar pairing, a separable collective Hamiltonian that is derived from the shell model effective interaction reproduces the full shell-model matrix elements with good accuracy. A version of the generator coordinate method that includes the isoscalar pairing amplitude as a coordinate also reproduces the shell model results well, an encouraging result for theories of collective motion, which can include more single-particle orbitals than the shell model. We briefly examine heavier nuclei relevant for experimental double-beta decay searches, in which shell-model calculations with all spin-orbit partners are not feasible; our estimates suggest that isoscalar pairing also plays a significant role in these nuclei, though one we are less able to quantify precisely.

    Comments:
    9 pages, 7 figures, published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1510.06824 [pdf]
    PRC(2016)·49 citations
  2. 02

    [Submitted on 23 Oct 2015]

    Interplay between Mach cone and radial expansion and its signal in -jet events

    Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

    We study the hydrodynamic response to jet quenching in expanding quark-gluon plasma (QGP) and its signal in the resulting particle distribution. The ideal hydrodynamic simulations of the -jet events in heavy-ion collisions are performed in a full (3 + 1)-dimensional setup. The jet-induced Mach cone and the radial expansion of the background mutually push and distort each other. As a result, the particle emission is suppressed in the direction in which the radial flow is pushed back by the Mach cone when the jet path is an off-central one. This is the direct signal of hydrodynamic response to the jetand, moreover, includes information about the jet path in the expanding QGP fluid.

    Comments:
    12 pages 10 figures; published in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1510.06966 [pdf]
    PRC(2016)·39 citations
  3. 03

    [Submitted on 22 Oct 2015] (cross-list from hep-ph)

    Transverse Spin Structure of the Nucleon

    Matthias Grosse Perdekamp🇺🇸 · Feng Yuan🇺🇸

    We review the current status and future perspectives of theory and experiments of transverse spin phenomena in high-energy scattering processes off nucleon targets and related issues in nucleon structure and QCD. Systematic exploration of transverse spin effects requires measurements in polarized deep-inelastic scattering, polarized pp collisions, and e+e- annihilations. Sophisticated QCD-based techniques are also needed to analyze the experimental data sets.

    Comments:
    28 pages, 16 figures, published in Annu. Rev. Nucl. Part. Sci., 2015
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1510.06783 [pdf]
    Ann.Rev.Nucl.Part.Sci.(2015)·47 citations
  4. 04

    [Submitted on 23 Oct 2015] (cross-list from astro-ph.HE)

    Measuring the basic parameters of neutron stars using model atmospheres

    V.F. Suleimanov · J. Poutanen · D. Klochkov · K. Werner

    Model spectra of neutron star atmospheres are nowadays widely used to fit the observed thermal X-ray spectra of neutron stars. This fitting is the key element in the method of the neutronstar radius determination. Here, we present the basic assumptions used for the neutron star atmosphere modeling as well as the main qualitative features of the stellar atmospheres leading to the deviations of the emergent model spectrum from blackbody. We describe the properties of two of our model atmosphere grids: (i) pure carbon atmospheres for relatively cool neutron stars (1--4 MK) and (ii) hot atmospheres with Compton scattering taken into account. The results obtained by applying these grids to model the X-ray spectra of the central compact object in supernova remnant HESS 1731-347, and two X-ray bursting neutron stars in low-mass X-ray binaries, 4U 1724-307 and 4U 1608-52, are presented. Possible systematic uncertainties associated with the obtained neutron star radii are discussed.

    Comments:
    20 pages, 20 figures. Accepted for publication in the European Physical Journal A topical issue on "Exotic Matter in Neutron Stars" . Based on the invited talk in MIAPP Workshop "The Many Faces of Neutron Stars", Garching, 24 August - 18 September 2015
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1510.06962 [pdf]
    EPJA(2016)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE