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Nuclear Theory·nucl-th

Wednesday·June 7, 2017

4 papers—1 primary·3 cross-listed

All4Primary1Cross-lists3
  1. 02

    [Submitted on 5 Jun 2017] (cross-list from hep-ph)

    Extracting the sigma-term from low-energy pion-nucleon scattering

    Jacobo Ruiz de Elvira🇨🇭 · Martin Hoferichter🇺🇸 · Bastian Kubis🇩🇪 · Ulf-G. Meißner🇩🇪

    We present an extraction of the pion-nucleon () scattering lengths from low-energy scattering, by fitting a representation based on Roy-Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large -term, MeV, in agreement with, albeit less precise than, the determination from pionic atoms.

    Comments:
    17 pages, 3 figures; journal version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1706.01465 [pdf]
    J.Phys.G(2018)·138 citations
  2. 03

    [Submitted on 5 Jun 2017] (cross-list from hep-ph)

    Analysis of vector boson production within TMD factorization

    Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

    We present a comprehensive analysis and extraction of the unpolarized transverse momentum dependent (TMD) parton distribution functions, which are fundamental constituents of the TMD factorization theorem. We provide a general review of the theory of TMD distributions, and present a new scheme of scale fixation. This scheme, called the -prescription, allows to minimize the impact of perturbative logarithms in the large range of scales and does not generate undesired power corrections. Within -prescription we consistently include the perturbatively calculable parts up to next-to-next-to-leading order (NNLO), and perform the global fit of the Drell-Yan and Z-boson production, which include the data of E288, Tevatron and LHC experiments. The nonperturbative part of the TMDs are explored checking a large variety of models. We support the obtained results by a study of theoretical uncertainties, perturbative convergence, and dedicated study of the range of applicability of the TMD factorization theorem. The considered nonperturbative models present significant differences in the fitting behavior, which allow us to clearly disfavor most of them. The numerical evaluations are provided by the "arTeMiDe" code, which is introduced in this work and that can be used for current/future TMD phenomenology.

    Comments:
    Major changes, improved analysis and corrected results. New figures also added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1706.01473 [pdf]
    EPJC(2018)·197 citations
  3. 04

    [Submitted on 6 Jun 2017] (cross-list from astro-ph.HE)

    Compact stars with sequential QCD phase transitions

    Mark G. Alford (1) · Armen Sedrakian (2) ((1) Physics Department · Washington University · St. Louis · (2) Frankfurt Institute for Advanced Studies)

    Compact stars may contain quark matter in their interiors at densities exceeding several times the nuclear saturation density. We explore models of such compact stars where there are two first-order phase transitions: the first from nuclear matter to a quark-matter phase, followed at higher density by another first-order transition to a different quark matter phase [e.g., from the two-flavor color superconducting (2SC) to the color-flavor-locked (CFL) phase). We show that this can give rise to two separate branches of hybrid stars, separated from each other and from the nuclear branch by instability regions and, therefore, to a new family of compact stars, denser than the ordinary hybrid stars. In a range of parameters, one may obtain twin hybrid stars (hybrid stars with the same masses but different radii) and even triplets where three stars, with inner cores of nuclear matter, 2SC matter, and CFL matter, respectively, all have the same mass but different radii.

    Comments:
    v2: 6 pages, 5 figures, matches published version. v1: 5 pages, 5 figures, uses RevTeX
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1706.01592 [pdf]
    PRL(2017)·191 citations

Affiliations

first authorsco-authorsvia INSPIRE