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Nuclear Theory·nucl-th

Wednesday·February 1, 2017

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 03

    [Submitted on 31 Jan 2017] (cross-list from hep-ph)

    Compositeness Of Quasibound States from Effective Field Theory

    Yuki Kamiya🇯🇵 · Tetsuo Hyodo🇯🇵

    The internal structure of exotic hadron candidates are studied from the viewpoint of the compositeness of near-threshold states. We focus on the Weinberg's weak-binding relation between the experimental observables and the compositeness of the state. First we extend the relation for quasibound states within the framework of the effective field theory. Next, considering the correction term, we develop a systematic method to estimate the uncertainty of compositeness in the weak-binding relation. Finally, applying the extended relation and the error evaluation method, we conclude that the structure of Lambda(1405) is dominated by the Kbar N component.

    Comments:
    8 pages, 1 figure, Proceedings of the 26th International Nuclear Physics Conference (INPC2016), Sep. 11-16, 2016, Adelaide, Australia
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1701.08941 [pdf]
    PoS(2017)·8 citations
  2. 04

    [Submitted on 31 Jan 2017] (cross-list from hep-lat)

    QCD Thermodynamics on the Lattice from the Gradient Flow

    Etsuko Itou🇯🇵 · Sinya Aoki🇯🇵

    To obtain the precise values of the bulk quantities and transport coefficients in quark-gluon-plasma phase, we propose that a direct calculation of the renormalized energy-momentum tensor (EMT) on the lattice using the gradient flow. From one-point function of EMT, authors in Ref.[1] obtained the interaction measure and thermal entropy. The results are consistent with the one obtained by the integral method. Based on the success, we try to measure the two-point function of EMT, which is related to the transport coefficients. Advantages of our method are (1) a clear signal because of the smearing effects of the gradient flow and (2) no need to calculate the wave function renormalization of EMT. In addition, we give a short remark on a comparison of the numerical cost between the positive- and adjoint-flow methods for fermions, needed to obtain the EMT in the (2+1) flavor QCD.

    Comments:
    8pages, Proceeding of the 26th International Nuclear Physics Conference (INPC2016)
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1701.08983 [pdf]
    PoS(2017)·3 citations
  3. 05

    [Submitted on 31 Jan 2017] (cross-list from hep-lat)

    Thermal D mesons from anisotropic lattice QCD

    Aoife Kelly🇮🇪 · Jon-Ivar Skullerud🇮🇪

    We present results for correlators and spectral functions of open charm mesons using 2+1 flavours of clover fermions on anisotropic lattices. The D mesons are found to dissociate close to the deconfinement crossover temperature Tc. Our preliminary results suggest a shift in the thermal D meson mass below Tc. Mesons containing strange quarks exhibit smaller thermal modifications than those containing light quarks.

    Comments:
    6 pages, 4 figures, talk presented at Lattice 2016, Southampton, and Confinement XII, Thessaloniki
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1701.09005 [pdf]
    EPJ Web Conf.(2017)·4 citations
  4. 06

    [Submitted on 31 Jan 2017] (cross-list from hep-ph)

    The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies

    Carlos Granados🇸🇪 · Stefan Leupold🇸🇪 · Elisabetta Perotti (Uppsala U.)🇸🇪

    Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion--Sigma--Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR).

    Comments:
    18 pages
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1701.09130 [pdf]
    EPJA(2017)·64 citations

Affiliations

first authorsco-authorsvia INSPIRE