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Nuclear Theory·nucl-th

Tuesday·May 26, 2015

13 papers—7 primary·6 cross-listed

All13Primary7Cross-lists6
  1. 08

    [Submitted on 23 May 2015] (cross-list from hep-ph)

    Effective Field Theory and Time-Reversal Violation in Light Nuclei

    E. Mereghetti (Los Alamos)🇺🇸 · U. van Kolck (Orsay, IPN & Arizona U.)🇫🇷

    Thanks to the unnaturally small value of the QCD vacuum angle , time-reversal () violation offers a window into physics beyond the Standard Model (SM) of particle physics. We review the effective-field-theory framework that establishes a clean connection between -violating mechanisms, which can be represented by higher-dimensional operators involving SM fields and symmetries, and hadronic interactions, which allow for controlled calculations of low-energy observables involving strong interactions. The chiral properties of -violating mechanisms leads to a pattern that should be identifiable in measurements of the electric dipole moments of the nucleon and light nuclei.

    Comments:
    35 pages. Accepted for publication in Ann. Rev. Nucl. Part. Sci. 65 (2015)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.06272 [pdf]
    Ann.Rev.Nucl.Part.Sci.(2015)·25 citations
  2. 09

    [Submitted on 23 May 2015] (cross-list from hep-ph)

    Cavitation in a quark gluon plasma with finite chemical potential and several transport coefficients

    S. M. Sanches Jr.🇧🇷 · D. A. Fogaça🇧🇷 · F. S. Navarra🇧🇷 · H. Marrochio🇧🇷

    We study the effects of a finite chemical potential on the occurrence of cavitation in a quark gluon plasma (QGP). We solve the evolution equations of second order viscous relativistic hydrodynamics using three different equations of state. The first one was derived in lattice QCD and represents QGP at zero chemical potential. It was previously used in the study of cavitation. The second equation of state also comes from lattice QCD and is a recent parametrization of the QGP at finite chemical potential. The third one is similar to the MIT equation of state with chemical potential and includes nonperturbative effects through the gluon condensates. We conclude that at finite chemical potential cavitation in the QGP occurs earlier than at zero chemical potential. We also consider transport coefficients from a holographic model of a non-conformal QGP at zero chemical potential. In this case cavitation does not occur.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.06335 [pdf]
    PRC(2015)·11 citations
  3. 10

    [Submitted on 23 May 2015] (cross-list from hep-ph)

    Four-point functions and the permutation group S4

    Gernot Eichmann🇩🇪 · Christian S. Fischer🇩🇪 · Walter Heupel🇩🇪

    Four-point functions are at the heart of many interesting physical processes. A prime example is the light-by-light scattering amplitude, which plays an important role in the calculation of hadronic contributions to the anomalous magnetic moment of the muon. In the calculation of such quantities one faces the challenge of finding a suitable and well-behaved basis of tensor structures in coordinate and/or momentum space. Provided all (or many) of the external legs represent similar particle content, a powerful tool to construct and organize such bases is the permutation group S4. We introduce an efficient notation for dealing with the irreducible multiplets of S4, and we highlight the merits of this treatment by exemplifying four-point functions with gauge-boson legs such as the four-gluon vertex and the light-by-light scattering amplitude. The multiplet analysis is also useful for isolating the important kinematic regions and the dynamical singularity content of such amplitudes. Our analysis serves as a basis for future efficient calculations of these and similar objects.

    Comments:
    23 pages, 9 figures, 5 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1505.06336 [pdf]
    PRD(2015)·81 citations
  4. 11

    [Submitted on 24 May 2015] (cross-list from hep-ph)

    Testing different formulations of leading-order anisotropic hydrodynamics

    Leonardo Tinti🇵🇱 · Radoslaw Ryblewski🇵🇱 · Wojciech Florkowski🇵🇱 · Michael Strickland🇺🇸

    A recently obtained set of the equations for leading-order (3+1)D anisotropic hydrodynamics is tested against exact solutions of the Boltzmann equation with the collisional kernel treated in the relaxation time approximation. In order to perform the detailed comparisons, the new anisotropic hydrodynamics equations are reduced to the boost-invariant and transversally homogeneous case. The agreement with the exact solutions found using the new anisotropic hydrodynamics equations is similar to that found using previous, less general, formulations of anisotropic hydrodynamics. In addition, we find that, when compared to a state-of-the-art second-order viscous hydrodynamics framework, leading-order anisotropic hydrodynamics better reproduces the exact solution for the pressure anisotropy and gives comparable results for the bulk pressure evolution. Finally, we compare the transport coefficients obtained using linearized anisotropic hydrodynamics with results obtained using second-order viscous hydrodynamics.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.06456 [pdf]
    NPA(2016)·27 citations
  5. 12

    [Submitted on 25 May 2015] (cross-list from hep-ph)

    Towards a consistent description of in-medium parton branching

    Liliana Apolinário🇵🇹 · Néstor Armesto🇵🇹 · Guilherme Milhano🇪🇸 · Carlos A. Salgado🇪🇸

    Ultra-relativistic heavy-ion collisions are a window of opportunity to study QCD matter under extreme conditions of temperature and density, such as the quark-gluon plasma. Among the several possibilities, the study of jet quenching - generic name given to in-medium energy loss modifications of the parton branching - is a powerful tool to assess the properties of this new state of matter. The description of the parton shower is very well understood in vacuum (controlled reference) and medium-induced modifications of this process can be experimentally accessed through jet measurements. Current experimental data, however, cannot be entirely described only with energy loss phenomena. Transverse momentum broadening and decoherence effects, both theoretically established by now, and their interplay are essential to build a consistent picture of the medium-modifications of the parton branching and to achieve a correct description of the current experimental data. In this write-up, we will present the latest developments that address such unified description.

    Comments:
    Proceedings Exited QCD 2015 (6 pages)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.06593 [pdf]
    Acta Phys.Polon.Supp.(2015)·1 citation
  6. 13

    [Submitted on 25 May 2015] (cross-list from hep-ph)

    Heavy Baryons with Strangeness in a Soliton Model

    J. P. Blanckenberg🇿🇦 · H. Weigel🇿🇦

    We present results from a chiral soliton model calculation for the spectrum of baryons with a single heavy quark (charm or bottom) and non-zero strangeness. We treat the strange components within a three flavor collective coordinate quantization of the soliton that fully accounts for light flavor symmetry breaking. Heavy baryons emerge by binding a heavy meson to the soliton. The dynamics of this heavy meson is described by the heavy quark effective theory with finite mass effects included.

    Comments:
    Ten pages, one figures, two tables, version to be published in PLB
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.06655 [pdf]
    PLB(2015)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE