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Nuclear Theory·nucl-th

Friday·June 3, 2016

14 papers—8 primary·6 cross-listed

All14Primary8Cross-lists6
  1. 09

    Chiral magnetic effect and anomalous transport from real-time lattice simulations

    Niklas Mueller🇩🇪 · Sören Schlichting🇺🇸 · Sayantan Sharma🇺🇸

    We present a first-principle study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian and Abelian gauge fields. Investigating the behavior of vector and axial currents during a sphaleron transition in the presence of an external magnetic field, we demonstrate how the interplay of the Chiral magnetic (CME) and Chiral separation effect (CSE) lead to the formation of a propagating wave. We further analyze the dependence of the magnitude of the induced vector current and the propagation of the wave on the amount of explicit chiral symmetry breaking due to finite quark mass.

    ↳ hep-phhep-latnucl-thPRL(2016)·69 citations
  2. 10

    Axion field and the quark nugget's formation at the QCD phase transition

    Xunyu Liang🇨🇦 · Ariel Zhitnitsky🇨🇦

    We study a testable dark matter (DM) model outside of the standard WIMP paradigm in which the observed ratio for visible and dark matter densities finds its natural explanation as a result of their common QCD origin when both types of matter (DM and visible) are formed at the QCD phase transition and both are proportional to . Instead of conventional "baryogenesis" mechanism we advocate a paradigm when the "baryogenesis" is actually a charge separation process which always occur in the presence of the odd axion field . In this scenario the global baryon number of the Universe remains zero, while the unobserved anti-baryon charge is hidden in form of heavy nuggets, similar to Witten's strangelets and compromise the DM of the Universe. We argue that the nuggets will be inevitably produced during the QCD phase transition as a result of Kibble-Zurek mechanism on formation of the topological defects during a phase transition. Relevant topological defects in our scenario are the closed bubbles made of the axion domain walls. These bubbles, in general, accrete the baryon (or anti baryon) charge, which eventually result in formation of the nuggets and anti-nuggets carrying a huge baryon (anti-baryon) charge. The main consequence of the model, is insensitive to the axion mass which may assume any value within the observationally allowed window . We also estimate the baryon to entropy ratio within this scenario. Finally, we comment on implications of these results to the axion search experiments, including microwave cavity and the Orpheus experiments.

    ↳ hep-phastro-ph.COnucl-thPRD(2016)·73 citations
  3. 11

    Trends in Nuclear Astrophysics

    Hendrik Schatz

    Nuclear Astrophysics is a vibrant field at the intersection of nuclear physics and astrophysics that encompasses research in nuclear physics, astrophysics, astronomy, and computational science. This paper is not a review. It is intended to provide an incomplete personal perspective on current trends in nuclear astrophysics and the specific role of nuclear physics in this field.

    ↳ nucl-exastro-ph.SRnucl-thJ.Phys.G(2016)·29 citations
  4. 12

    JIMWLK evolution of the odderon

    T. Lappi🇫🇮 · A. Ramnath🇫🇮 · K. Rummukainen🇫🇮 · H. Weigert🇿🇦

    We study the effects of a parity-odd "odderon" correlation in JIMWLK renormalization group evolution at high energy. Firstly we show that in the eikonal picture where the scattering is described by Wilson lines, one obtains a strict mathematical upper limit for the magnitude of the odderon amplitude compared to the parity even pomeron one. This limit increases with N_c, approaching infinity in the infinite N_c limit. We use a systematic extension of the Gaussian approximation including both 2- and 3-point correlations which enables us to close the system of equations even at finite N_c. In the large-N_c limit we recover an evolution equation derived earlier. By solving this equation numerically we confirm that the odderon amplitude decreases faster in the nonlinear case than in the linear BFKL limit. We also point out that, in the 3-point truncation at finite N_c, the presence of an odderon component introduces azimuthal angular correlations ~ cos(n phi) at all n.

    ↳ hep-phnucl-thPRD(2016)·35 citations
  5. 13

    Layers of deformed instantons in holographic baryonic matter

    Florian Preis🇦🇹 · Andreas Schmitt🇬🇧

    We discuss homogeneous baryonic matter in the decompactified limit of the Sakai-Sugimoto model, improving existing approximations based on flat-space instantons. We allow for an anisotropic deformation of the instantons in the holographic and spatial directions and for a density-dependent distribution of arbitrarily many instanton layers in the bulk. Within our approximation, the baryon onset turns out to be a second-order phase transition, at odds with nature, and there is no transition to quark matter at high densities, at odds with expectations from QCD. This changes when we impose certain constraints on the shape of single instantons, motivated by known features of holographic baryons in the vacuum. Then, a first-order baryon onset and chiral restoration at high density are possible, and at sufficiently large densities two instanton layers are formed dynamically. Our results are a further step towards describing realistic, strongly interacting matter over a large density regime within a single model, desirable for studies of compact stars.

    ↳ hep-phhep-thnucl-thJHEP(2016)·39 citations
  6. 14

    Exploring QCD dynamics in medium energy semiexclusive collisions

    A.B. Larionov🇩🇪 · M. Strikman🇺🇸

    We demonstrate that studies of the semiexclusive large angle photon - nucleus reactions: with tagged photon beams of energies GeV which can be performed in Hall D at Thomas Jefferson National Acceleration Facility (TJNAF) would allow to probe several aspects of the QCD dynamics: establish the -range in which transition from soft to hard dynamics occurs, compare the strength of the interaction of various mesons and baryons with nucleons at the energies of few GeV, as well as look for the color transparency effects.

    ↳ hep-phhep-exnucl-thPLB(2016)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE