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Nuclear Theory·nucl-th

Tuesday·March 17, 2015

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 06

    A Modest Revision of the Standard Model

    G. J. Stephenson Jr.🇺🇸 · T. Goldman🇺🇸

    With a modest revision of the mass sector of the Standard Model, the systematics of the fermion masses and mixings can be fully described and interpreted as providing information on matrix elements of physics beyond the Standard Model. A by-product is a reduction of the largest Higgs Yukawa fine structure constant by an order of magnitude. The extension to leptons provides for insight on the difference between quark mixing and lepton mixing as evidenced in neutrino oscillations. The large difference between the scale for up-quark and down-quark masses is not addressed. In this approach, improved detail and accuracy of the elements of the current mixing matrices can extend our knowledge and understanding of physics beyond the Standard Model.

    ↳ hep-phnucl-th2 citations
  2. 07

    Relativistic hydrodynamics from quantum field theory on the basis of the generalized Gibbs ensemble method

    Tomoya Hayata🇯🇵 · Yoshimasa Hidaka🇯🇵 · Masaru Hongo🇯🇵 · Toshifumi Noumi🇯🇵

    We derive relativistic hydrodynamics from quantum field theories by assuming that the density operator is given by a local Gibbs distribution at initial time. We decompose the energy-momentum tensor and particle current into nondissipative and dissipative parts, and analyze their time evolution in detail. Performing the path-integral formulation of the local Gibbs distribution, we microscopically derive the generating functional for the nondissipative hydrodynamics.We also construct a basis to study dissipative corrections. In particular, we derive the first-order dissipative hydrodynamic equations without a choice of frame such as the Landau-Lifshitz or Eckart frame.

    ↳ hep-phcond-mat.stat-mechhep-thnucl-thPRD(2015)·72 citations
  3. 08

    Collective String Interactions in AdS/QCD and High-Multiplicity pA Collisions

    Ioannis Iatrakis🇺🇸 · Adith Ramamurti🇺🇸 · Edward Shuryak🇺🇸

    QCD strings originate from high-energy scattering in the form of Reggeons and Pomerons, and have been studied in some detail in lattice numerical simulations. Production of multiple strings, with their subsequent breaking, is now a mainstream model of high energy and collisions. Recent LHC experiments revealed that high multiplicity end of such collisions show interesting collective effects. This ignited an interest in the interaction of QCD strings and multi-string dynamics. Holographic models, collectively known as AdS/QCD, developed in the last decade, describe both hadronic spectroscopy and basic thermodynamics, but so far no studies of the QCD strings have been done in this context. The subject of this paper is to do this. First, we study in more detail the scalar sector of hadronic spectroscopy, identifying "glueballs" and "scalar mesons," and calculate the degree of their mixing. The QCD strings, holographic images of the fundamental strings, thus have a "gluonic core" and a "sigma cloud." The latter generates exchanges and collectivization of the strings, affecting, at a certain density, the chiral condensate and even the minimum of the effective string potential, responsible for the very existence of the QCD strings. Finally, we run dynamical simulations of the multi-string systems, in the "spaghetti" setting approximating central collisions, and specify conditions for their collectivization into a black hole, or the dual QGP fireball.

    ↳ hep-phhep-thnucl-thPRD(2015)·18 citations
  4. 09

    Galilean-Invariant XEFT

    Eric Braaten🇺🇸

    XEFT is a low-energy effective field theory for charm mesons and pions that provides a systematically improvable description of the X(3872) resonance. A Galilean-invariant formulation of XEFT is introduced to exploit the fact that mass is very nearly conserved in the transition D*0 --> D0 pi0. The transitions D*0 --> D0 pi0 and X --> D0 D0-bar pi0 are described explicitly in XEFT. The effects of the decay D*0 --> D0 gamma and of short-distance decay modes of the X(3872), such as J/psi --> pi+ pi-, can be taken into account by using complex on-shell renormalization schemes for the D*0 propagator and for the D*0 D0-bar propagator in which the positions of their complex poles are specified. Galilean-invariant XEFT is used to calculate the D*0 D0-bar scattering length to next-to-leading order. Galilean invariance ensures the cancellation of ultraviolet divergences without the need for truncating an expansion in powers of the ratio of the pion and charm meson masses.

    ↳ hep-phnucl-thPRD(2015)·57 citations

Affiliations

first authorsco-authorsvia INSPIRE