PaperPanorama
FAQ

Nuclear Theory·nucl-th

Wednesday·February 3, 2016

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 06

    [Submitted on 1 Feb 2016] (cross-list from hep-ph)

    CPT, CP, and C transformations of fermions, and their consequences, in theories with B-L violation

    Susan Gardner🇺🇸 · Xinshuai Yan🇺🇸

    We consider the transformation properties of fermions under the discrete symmetries CPT, CP, and C in the presence of B-L violation. We thus generalize the analysis of the known properties of Majorana neutrinos, probed via neutrinoless double beta decay, to include the case of Dirac fermions with B-L violation, which can be probed via neutron-antineutron oscillations. We show that the resulting CPT phase has implications for the interplay of neutron-antineutron oscillations with external fields and sources and consider the differences in the Majorana dynamics of neutrinos and neutrons in the context of theories with self-conjugate isospin I=0 and I=1/2 fields.

    Comments:
    23 pages; refs. and acknowledgement added with minor changes; published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1602.00693 [pdf]
    PRD(2016)·25 citations
  2. 07

    [Submitted on 2 Feb 2016] (cross-list from hep-ph)

    The radius of the rho meson determined from its decay constant

    A.F. Krutov🇷🇺 · R.G. Polezhaev🇷🇺 · V.E. Troitsky🇷🇺

    We present a unified model describing electroweak properties of the pi and rho mesons. Using a general method of relativistic parametrization of matrix elements of local operators, adjusted for the nondiagonal in total angular momentum case, we calculate the rho-meson lepton-decay constant f_rho using the same parameters of free constituent quarks that have ensured exclusively good results for the pi meson previously. The only free parameter, characterizing quark interactions, which include additional spin-spin contribution and hence differ from the -meson case, is fixed by matching the decay constant to its experimental value. The mean square charge radius is calculated, <r^2_rho>=(0.56+-0.04) fm^2. This result verifies, for the rho-meson case, the conjecture of equality between electromagnetic and strong radii of hadrons tested previously for proton, pi and K mesons.

    Comments:
    8 pages, 2 figures, revtex
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1602.00907 [pdf]
    PRD(2016)·43 citations
  3. 08

    [Submitted on 2 Feb 2016] (cross-list from hep-ph)

    Interplay of quark and meson degrees of freedom in near-threshold states: A practical parametrisation for line shapes

    F.-K. Guo🇨🇳 · C. Hanhart🇩🇪 · Yu.S. Kalashnikova🇷🇺 · P. Matuschek🇩🇪 · R.V. Mizuk🇷🇺 · A.V. Nefediev🇷🇺 · Q. Wang🇩🇪 · J.-L. Wynen🇩🇪

    We propose a practical parametrisation for the line shapes of near-threshold states compatible with all requirements of unitarity and analyticity. The coupled-channel system underlying the proposed parametrisation includes bare poles and an arbitrary number of elastic and inelastic channels treated fully nonperturbatively. The resulting formulae are general enough to be used for a simultaneous analysis of the data in all available production and decay channels of the (system of) state(s) under consideration for a quite wide class of reactions. As an example, we fit the experimental data currently available for several decay channels for the charged states in the spectrum of bottomonia and find a good overall description of the data. We find the present data to be consistent with the as a virtual state and with the as a resonance, both residing very close to the and threshold, respectively.

    Comments:
    LaTeX2e, 19 pages, 10 figures, version published in Phys.Rev.D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1602.00940 [pdf]
    PRD(2016)·93 citations
  4. 09

    [Submitted on 2 Feb 2016] (cross-list from hep-ph)

    Theoretical Developments in QCD Jet Energy Loss

    Yacine Mehtar-Tani🇺🇸

    We review the recent developments in the theory of jet-quenching. First, we analyze the coherent vacuum cascade and incoherent medium-induced cascade separately. We then discuss the interplay between the two kinds of cascade and the resulting partial decoherence of the inner jet structure. Finally, we report on recent calculations of higher-order corrections. In particular, the dominant radiative corrections to jet observables that yield the renormalization of the jet-quenching parameter are addressed.

    Comments:
    8 pages, 3 figures, invited plenary talk, to appear in the proceedings of Quark Matter 2015 conference, Kobe, Japan
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1602.01047 [pdf]
    NPA(2016)·5 citations
  5. 10

    [Submitted on 2 Feb 2016] (cross-list from astro-ph.HE)

    Measuring the neutron star equation of state using X-ray timing

    Anna L. Watts · Nils Andersson · Deepto Chakrabarty · Marco Feroci · Kai Hebeler · Gianluca Israel · Frederick K. Lamb · M. Coleman Miller · Sharon Morsink · Feryal Özel · Alessandro Patruno · Juri Poutanen and 6 other authors

    One of the primary science goals of the next generation of hard X-ray timing instruments is to determine the equation of state of the matter at supranuclear densities inside neutron stars, by measuring the radius of neutron stars with different masses to accuracies of a few percent. Three main techniques can be used to achieve this goal. The first involves waveform modelling. The flux we observe from a hotspot on the neutron star surface offset from the rotational pole will be modulated by the star's rotation, giving rise to a pulsation. Information about mass and radius is encoded into the pulse profile via relativistic effects, and tight constraints on mass and radius can be obtained. The second technique involves characterising the spin distribution of accreting neutron stars. The most rapidly rotating stars provide a very clean constraint, since the mass-shedding limit is a function of mass and radius. However the overall spin distribution also provides a guide to the torque mechanisms in operation and the moment of inertia, both of which can depend sensitively on dense matter physics. The third technique is to search for quasi-periodic oscillations in X-ray flux associated with global seismic vibrations of magnetars (the most highly magnetized neutron stars), triggered by magnetic explosions. The vibrational frequencies depend on stellar parameters including the dense matter equation of state. We illustrate how these complementary X-ray timing techniques can be used to constrain the dense matter equation of state, and discuss the results that might be expected from a 10m instrument. We also discuss how the results from such a facility would compare to other astronomical investigations of neutron star properties. [Modified for arXiv]

    Comments:
    To appear in Reviews of Modern Physics as a Colloquium, 23 pages, 9 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1602.01081 [pdf]
    RMP(2016)·393 citations

Affiliations

first authorsco-authorsvia INSPIRE