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Nuclear Theory·nucl-th

Friday·March 24, 2017

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 22 Mar 2017]

    Heavy quark dynamics within a Boltzmann transport model: radiative vs collisional energy loss

    G. Coci (1 and 2)🇮🇹 · F. Scardina (2)🇮🇹 · V. Greco (1 and 2) ((1) University of Catania Department of Physics and Astronomy (2) INFN Laboratori Nazionali del Sud)🇮🇹

    We discuss the propagation of heavy quarks (charm and bottom) through the QGP by means of a relativistic Boltzmann transport approach including both collisional and radiative energy loss mechanisms. In particular we investigate the impact of induced gluon radiation by dynamical QCD medium implementing in our transport model a formula for the emitted gluon spectrum calculated in a higher-twist scheme. We notice that in the region of high transverse momentum ( GeV) radiative processes play an essential role giving a dominant contribution to the generation of and at momentum values for which the energy loss by collisions is in the perturbative regime.

    Comments:
    4 pages, 4 figures, proceeding of Hot Quarks 2016: Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions. (HQ2016) 12-17 Sep 2016. South Padre Island, Texas
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1703.07828 [pdf]
    J.Phys.Conf.Ser.(2017)·2 citations
  2. 02

    [Submitted on 23 Mar 2017]

    Three-body bound states with zero-range interaction in the Bethe-Salpeter approach

    E. Ydrefors🇧🇷 · J. H. Alvarenga Nogueira🇧🇷 · V. Gigante🇧🇷 · T. Frederico🇧🇷 · V.A. Karmanov🇷🇺

    The Bethe-Salpeter equation for three bosons with zero-range interaction is solved for the first time. For comparison the light-front equation is also solved. The input is the two-body scattering length and the outputs are the three-body binding energies, Bethe-Salpeter amplitudes and light-front wave functions. Three different regimes are analyzed: ({\it i}) For weak enough two-body interaction the three-body system is unbound. ({\it ii}) For stronger two-body interaction a three-body bound state appears. It provides an interesting example of a deeply bound Borromean system. ({\it iii}) For even stronger two-body interaction this state becomes unphysical with a negative mass squared. However, another physical (excited) state appears, found previously in light-front calculations. The Bethe-Salpeter approach implicitly incorporates three-body forces of relativistic origin, which are attractive and increase the binding energy.

    Comments:
    13 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1703.07981 [pdf]
    PLB(2017)·15 citations
  3. 03

    [Submitted on 23 Mar 2017]

    Dynamical evolution of critical fluctuations and its observation in heavy ion collisions

    Miki Sakaida🇯🇵 · Masayuki Asakawa🇯🇵 · Hirotsugu Fujii🇯🇵 · Masakiyo Kitazawa🇯🇵

    We study time evolution of critical fluctuations of conserved charges near the QCD critical point in the context of relativistic heavy ion collisions. A stochastic diffusion equation is employed in order to describe the diffusion property of the critical fluctuation arising from the coupling of the order parameter field to conserved charges. We show that the diffusion property gives rise to a possibility of probing the early time fluctuations through the rapidity window dependence of the second-order cumulant and correlation function of conserved charges. It is pointed out that their non-monotonic behaviors as functions of the rapidity interval are robust experimental signals for the existence of the critical enhancement around the QCD critical point.

    Comments:
    13 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1703.08008 [pdf]
    PRC(2017)·44 citations
  4. 04

    [Submitted on 22 Mar 2017] (cross-list from nucl-ex)

    Experimentally Study the Deep Dirac Levels with High-Intensity Lasers

    Xiaopeng Zhang · Changbo Fu · Dechang Dai

    Various theories have predicted the deep Dirac levels (DDLs) in atoms for many years. However, the existence of the DDL is still under debating, and need to be confirmed experimentally. With the development of high intensive lasers, nowadays, electrons can been accelerated to relativistic energy by high intensive lasers, electron-positron pairs can be created, and nuclear reactions can been ignited, which provide a new tool to explore the DDL related fields. In this paper, we propose a new experimental method to study the DDL levels by monitoring nuclei's orbital electron capture life time in plasma induced by high intensive lasers. If a DDL exists, a nuclear electron capture rate could be enhanced by factor of over , which makes it practically detectable in nowadays high intensive laser environments.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1703.07837 [pdf]
    0 citations
  5. 05

    [Submitted on 23 Mar 2017] (cross-list from hep-ph)

    Charmonium spectrum with a Dirac potential model in the momentum space

    D. Molina🇨🇴 · M. De Sanctis🇨🇴 · C. Fernandez-Ramirez🇲🇽

    We study the charmonium spectrum using a complete one gluon exchange approach based on a phenomenological relativistic potential model with Dirac spinors in momentum space. We use phenomenological screening factors to include vacuum quantum effects. Our formulation does not rely on nonrelativistic approximations. We fit the lowest-lying charmonia (below the threshold) and predict the higher-lying resonances of the spectrum. In general, we reproduce the overall structure of the charmonium spectrum and, in particular, we can reasonably describe the resonance mass as (mostly) a state. The numerical values of the free parameters of the model are determined taking into account also the experimental uncertainties of the resonance energies. In this way, we are able to obtain the uncertainties of the theoretical resonance masses and the correlation among the free parameters of the model.

    Comments:
    16 pages, 3 figures, 6 tables, to be published in Physical Review D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1703.08097 [pdf]
    PRD(2017)·17 citations
  6. 06

    [Submitted on 23 Mar 2017] (cross-list from hep-ph)

    Effects of magnetic field on the plasma evolution in relativistic heavy-ion collisions

    Arpan Das🇮🇳 · Shreyansh S. Dave🇮🇳 · P. S. Saumia🇷🇺 · Ajit M. Srivastava🇮🇳

    Very strong magnetic fields can arise in non-central heavy-ion collisions at ultrarelativistic energies, which may not decay quickly in a conducting plasma. We carry out relativistic magnetohydrodynamics (RMHD) simulations to study the effects of this magnetic field on the evolution of the plasma and on resulting flow fluctuations in the ideal RMHD limit. Our results show that magnetic field leads to enhancement in elliptic flow for small impact parameters while it suppresses it for large impact parameters (which may provide a signal for initial stage magnetic field). Interestingly, we find that magnetic field in localized regions can temporarily increase in time as evolving plasma energy density fluctuations lead to reorganization of magnetic flux. This can have important effects on chiral magnetic effect. Magnetic field has non-trivial effects on the power spectrum of flow fluctuations. For very strong magnetic field case one sees a pattern of even-odd difference in the power spectrum of flow coefficients arising from reflection symmetry about the magnetic field direction if initial state fluctuations are not dominant. We discuss the situation of nontrivial magnetic field configurations arising from collision of deformed nuclei and show that it can lead to anomalous elliptic flow. Special (crossed body-body) configurations of deformed nuclei collision can lead to presence of quadrupolar magnetic field which can have very important effects on the rapidity dependence of transverse expansion (similar to {\it beam focusing} from quadrupole fields in accelerators).

    Comments:
    15 pages, 16 figures, New figure included showing effect of magnetic field on momentum eccentricity
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph)
    arXiv:
    1703.08162 [pdf]
    PRC(2017)·77 citations

Affiliations

first authorsco-authorsvia INSPIRE