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Nuclear Theory·nucl-th

Friday·May 17, 2019

8 papers—4 primary·4 cross-listed

All8Primary4Cross-lists4
  1. 05

    [Submitted on 15 May 2019] (cross-list from astro-ph.HE)

    Nuclear Dominated Accretion Flows in Two Dimensions. II. Ejecta dynamics and nucleosynthesis for CO and ONe white dwarfs

    Rodrigo Fernández · Ben Margalit · Brian D. Metzger

    We study mass ejection from accretion disks formed in the merger of a white dwarf with a neutron star or black hole. These disks are mostly radiatively-inefficient and support nuclear fusion reactions, with ensuing outflows and electromagnetic transients. Here we perform time-dependent, axisymmetric hydrodynamic simulations of these disks including a physical equation of state, viscous angular momentum transport, a coupled -isotope nuclear network, and self-gravity. We find no detonations in any of the configurations studied. Our global models extend from the central object to radii much larger than the disk. We evolve these global models for several orbits, as well as alternate versions with an excised inner boundary to much longer times. We obtain robust outflows, with a broad velocity distribution in the range km s. The outflow composition is mostly that of the initial white dwarf, with burning products mixed in at the level by mass, including up to of Ni. These heavier elements (plus He) are ejected within of the rotation axis, and should have higher average velocities than the lighter elements that make up the white dwarf. These results are in broad agreement with previous one- and two-dimensional studies, and point to these systems as progenitors of rapidly-rising ( few day) transients. If accretion onto the central BH/NS powers a relativistic jet, these events could be accompanied by high energy transients with peak luminosities erg s and peak durations of up to several minutes, possibly accounting for events like CDF-S XT2.

    Comments:
    Accepted by MNRAS. Updated Fig 10 (velocity distribution for NS or BH) and added new Fig 15 (comparison with exploding model from Paper I). Minor changes otherwise
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    1905.06343 [pdf]
    MNRAS(2019)·45 citations
  2. 06

    [Submitted on 15 May 2019] (cross-list from hep-lat)

    Valence parton distribution function of pion from fine lattice

    Taku Izubuchi🇺🇸 · Luchang Jin🇺🇸 · Christos Kallidonis🇺🇸 · Nikhil Karthik🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Charles Shugert🇺🇸 · Sergey Syritsyn🇺🇸

    We present a lattice QCD study of valence parton distribution inside the pion within the framework of Large Momentum Effective Theory. We use a mixed action approach with 1-HYP smeared valence Wilson clover quarks on 2+1 flavor HISQ sea with the valence quark mass tuned to 300 MeV pion mass. We use lattice at a fine lattice spacing fm for this computation. We renormalize the quasi-PDF matrix element in the non-perturbative RI-MOM scheme. As a byproduct, we test the validity of 1-loop matching procedure by comparing the RI-MOM renormalized quasi-PDF matrix element with off-shell quark external states as computed in the continuum 1-loop perturbation theory with the lattice results at and 0.06 fm. By applying the RI-MOM to one-loop matching, implemented through a fit to phenomenologically motivated PDFs, we obtain the valence PDF of pion.

    Comments:
    25 pages, 22 figures; version published in PRD
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1905.06349 [pdf]
    PRD(2019)·139 citations
  3. 07

    [Submitted on 15 May 2019] (cross-list from hep-th)

    Strong Coupling Universality at Large N for Pure CFT Thermodynamics in 2+1 dimensions

    Oliver DeWolfe🇺🇸 · Paul Romatschke🇺🇸

    Pure CFTs have vanishing -function at any value of the coupling. One example of a pure CFT is the O(N) Wess-Zumino model in 2+1 dimensions in the large N limit. This model can be analytically solved at finite temperature for any value of the coupling, and we find that its entropy density at strong coupling is exactly equal to 31/35 of the non-interacting Stefan-Boltzmann result. We show that a large class of theories with equal numbers of N-component fermions and bosons, supersymmetric or not, for a large class of interactions, exhibit the same universal ratio. For unequal numbers of fermions and bosons we find that the strong-weak thermodynamic ratio is bounded to lie in between 4/5 and 1.

    Comments:
    11 pages, 2 figures; v2: references added
    Subjects:
    High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
    arXiv:
    1905.06355 [pdf]
    JHEP(2019)·16 citations
  4. 08

    [Submitted on 16 May 2019] (cross-list from hep-ph)

    Coherent and incoherent vector meson electroproduction in the future electron-ion colliders: the hot-spot predictions

    M. Krelina🇨🇱 · V. P. Goncalves🇧🇷 · J. Cepila🇨🇿

    One of the more promising observables to probe the high energy regime of the QCD dynamics in the future Electron-Ion Colliders (EIC) is the exclusive vector meson production cross section in coherent and incoherent interactions. Such processes measure the average spatial distribution of gluons in the target as well the fluctuations and correlations in the gluon density. In this paper we present a comprehensive analysis of the energy, photon virtuality, atomic number and momentum transfer dependencies of the coherent and incoherent cross sections considering two different models for the nuclear profile function. In particular, we present the predictions of the hot-spot model, which assumes the presence of subnucleonic degrees of freedom and an energy-dependent profile. Our results indicate that the analysis of the ratio between the incoherent and coherent cross sections and the momentum transfer distributions in the future EIC can be useful to constrain the description of the hadronic structure at high energies.

    Comments:
    11 pages, 9 figures, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1905.06759 [pdf]
    NPA(2019)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE