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Nuclear Theory·nucl-th

Monday·September 7, 2015

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 4 Sept 2015]

    Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

    Chen Ji🇨🇦 · Oscar Javier Hernandez🇨🇦 · Nir Nevo Dinur🇮🇱 · Sonia Bacca🇨🇦 · Nir Barnea🇮🇱

    We present calculations of nuclear structure effects to the Lamb shift in light muonic atoms. We adopt a modern ab-initio approach by combining state-of-the-art nuclear potentials with the hyperspherical harmonics method. Our calculations are instrumental to the determination of nuclear charge radii in the Lamb shift measurements, which will shed light on the proton radius puzzle.

    Comments:
    Proceedings of the 21st International Conference on Few-Body Problems in Physics. May 18-22, 2015. Chicago, Illinois, USA
    Subjects:
    Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
    arXiv:
    1509.01430 [pdf]
    EPJ Web Conf.(2016)·7 citations
  2. 02

    [Submitted on 4 Sept 2015]

    Interactions of Meson in Relativistic Heavy-Ion Collisions

    Shaheen Irfan · Faisal Akram · Bilal Masud

    We calculate the absorbtion cross-sections of mesons by and mesons including anomalous processes using an effective hadronic Lagrangian. The enhancement of Bc production is expected due to QGP formation in heavy-ion experiments. However it is also expected that the production rate of Bc meson can be affected due to the interaction with comovers. These processes are relevant for experiments at RHIC. Thermal average cross-sections of are evaluated with form factor when a cut off parameter in it is 1 and 2 GeV. Using these thermal average cross-sections in the kinetic equation we investigate the time evolution of mesons due to dissociation in the hadronic matter formed at RHIC.

    Comments:
    This paper was presented in 7th International Meeting on Particles and Fields ,1st - 4th April 2015 at Center for High Energy Physics, Punjab University, Lahore, Pakistan
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.01525 [pdf]
    PRC(2019)·4 citations
  3. 03

    [Submitted on 4 Sept 2015]

    Toward an understanding of the and puzzle for heavy quarks

    Francesco Scardina🇮🇹 · Santosh K Das🇮🇹 · Salvatore Plumari🇮🇹 · Jessica I. Bellone🇮🇹 · Vincenzo Greco🇮🇹

    One of the primary aims of the ongoing nuclear collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies is to create a Quark Gluon Plasma (QGP). The heavy quarks constitutes a unique probe of the QGP properties. Both at RHIC and LHC energies a puzzling relation between the nuclear modification factor and the elliptic flow related to heavy quark has been observed which challenged all the existing models.\\ We discuss how the temperature dependence of the heavy quark drag coefficient can address for a large part of such a puzzle. We have considered four different models to evaluate the temperature dependence of drag and diffusion coefficients propagating through a quark gluon plasma (QGP). All the four different models are set to reproduce the same experimentally observed at RHIC energy. We have found that for the same one can generate times more depending on the temperature dependence of the heavy quark drag coefficient.

    Comments:
    proceedings of the 2015 Hard Probes conference
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1509.01551 [pdf]
    Nucl.Part.Phys.Proc.(2016)·5 citations
  4. 04

    [Submitted on 4 Sept 2015] (cross-list from hep-ph)

    Heavy quark potential from QCD-related effective coupling

    Cesar Ayala🇪🇸 · Pedro Gonzalez🇪🇸 · Vicente Vento🇪🇸

    We implement our past investigations in the quark-antiquark interaction through a non-perturbative running coupling defined in terms of a gluon mass function, similar to that used in some Schwinger-Dyson approaches. This coupling leads to a quark-antiquark potential, which satisfies not only asymptotic freedom but also describes linear confinement correctly. From this potential, we calculate the bottomonium and charmonium spectra below the first open flavor meson-meson thresholds and show that for a small range of values of the free parameter determining the gluon mass function an excellent agreement with data is attained.

    Comments:
    13 pages, 4 figures; v3: version accepted for publication in Journal of Physics G
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1509.01382 [pdf]
    J.Phys.G(2016)·8 citations
  5. 05

    [Submitted on 4 Sept 2015] (cross-list from hep-ph)

    Preserving Local Gauge Invariance with t-Channel Regge Exchange

    Helmut Haberzettl🇺🇸 · Xiao-Yun Wang🇨🇳 · Jun He🇨🇳

    Considering single-meson photo- and electroproduction off a baryon, it is shown how to restore local gauge invariance that was broken by replacing standard Feynman-type meson exchange in the t-channel by exchange of a Regge trajectory. This is achieved by constructing a contact current whose four-divergence cancels the gauge-invariance-violating contributions resulting from all states above the base state on the Regge trajectory. To illustrate the procedure, modifications necessary for the process are discussed in some detail. We also provide the general expression for the contact current for an arbitrary reaction.

    Comments:
    11 pages, 2 figures, RevTeX4-1
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1509.01536 [pdf]
    PRC(2015)·24 citations
  6. 06

    [Submitted on 4 Sept 2015] (cross-list from astro-ph.HE)

    Neutrino flavor instabilities in a time-dependent supernova model

    Sajad Abbar🇺🇸 · Huaiyu Duan (UNM)🇺🇸

    A dense neutrino medium such as that inside a core-collapse supernova can experience collective flavor conversion or oscillations because of the neutral-current weak interaction among the neutrinos. This phenomenon has been studied in a restricted, stationary supernova model which possesses the (spatial) spherical symmetry about the center of the supernova and the (directional) axial symmetry around the radial direction. Recently it has been shown that these spatial and directional symmetries can be broken spontaneously by collective neutrino oscillations. In this paper we analyze the neutrino flavor instabilities in a time-dependent supernova model. Our results show that collective neutrino oscillations start at approximately the same radius in both the stationary and time-dependent supernova models unless there exist very rapid variations in local physical conditions on timescales of a few microseconds or shorter. Our results also suggest that collective neutrino oscillations can vary rapidly with time in the regimes where they do occur which need to be studied in time-dependent supernova models.

    Comments:
    5 pages, 2 figures, version to appear in PLB
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1509.01538 [pdf]
    PLB(2015)·72 citations

Affiliations

first authorsco-authorsvia INSPIRE