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Nuclear Theory·nucl-th

Wednesday·April 25, 2018

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 01

    [Submitted on 23 Apr 2018]

    New charm resonances and interactions in a hadron gas

    L. M. Abreu🇧🇷 · K. P. Khemchandani🇧🇷 · A. Martínez Torres🇧🇷 · F. S. Navarra🇧🇷 · M. Nielsen🇧🇷

    In relativistic heavy ion collisions, after the quark gluon plasma (QGP) phase there is a hadron gas (HG) phase. In both phases may be formed and destroyed. In this note we study the interactions with other mesons in the hadron gas phase. Making use of effective field Lagrangians we obtain the cross sections for the production and absorption processes. With respect to the existing calculations, the improvements introduced here are the inclusion of and 's in the effective Lagrangian approach and the inclusion of processes involving the new exotic charmonium states and . We conclude that the interactions between and all the considered mesons reduce the original abundance ( determined at the end of the quark gluon plasma phase ) by 20 \% and 24 \% in RHIC and LHC collisions respectively. Consequently, any really significant change in the abundance comes from dissociation and regeneration processes in the QGP phase.

    Comments:
    4 pages, 2 figures. Contribution to the Proceedings of the XIV HADRON PHYSICS, 2018, MARCH 18-23, FLORIANOPOLIS, BRAZIL
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1804.08775 [pdf]
    0 citations
  2. 02

    [Submitted on 24 Apr 2018]

    A comparative study of Compact Objects using 3 models: Walecka Model, PAL Model, and M.I.T. Bag Model

    Fabio Kopp🇧🇷 · Alex Quadros🇧🇷 · Guilherme Volkmer🇧🇷 · Moises Razeira🇧🇷 · Magno Machado🇧🇷 · Dimiter Hadjimichef🇧🇷 · Cesar Augusto Zen Vasconcellos🇧🇷

    Compact objects are the name used to classify the following objects: white dwarf, neutron star and black holes. In addition to them, some authors have suggested that in the core of a neutron star we may have the quarks u,d,s and c. In this work we investigate the structure of neutron star and strange star, described by the Tolman-Openheimer-Volkof equations. For the neutron star, we used the relativistic EoS from Walecka's model and the non-relativistic EoS PAL model. For the strange star, we used the M.I.T. bag model. We obtain results for the mass-radius relation and then we compared ours results with the actual pulsar data recently observed PSR J1614-2230 with a mass .

    Comments:
    Poster presented at the XIV International Workshop on Hadron Physics, Florianópolis, Brazil, March 2018
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1804.08785 [pdf]
    0 citations
  3. 03

    [Submitted on 24 Apr 2018]

    Intertwined effects of pairing and deformation on neutron halos in magnesium isotopes

    H. Nakada · K. Takayama

    Matter radii of the Mg nuclei are investigated by self-consistent Hartree-Fock-Bogolyubov calculations assuming the axial symmetry. With the semi-realistic M3Y-P6 interaction, the -dependence of the matter radii observed in the experiments is reproduced excellently. Both the pairing and the deformation play significant roles in an intertwined manner. The Mg nucleus has a smaller radius than the neighboring even- nuclei, which is attributed to its smaller deformation. In contrast, a neutron halo is obtained in Mg. We point out that, in contrast to the pairing anti-halo effect that may operate on the even- nuclei, the pair correlation enhances halos in odd- nuclei, owing to the new mechanism which we call \textit{unpaired-particle haloing}. The halo in Mg is predicted to have peanut shape in its intrinsic state, reflecting -wave contribution, as in Mg. The -dependence of the deformation is significant again, by which the single-particle level dominated by the -wave component comes down.

    Comments:
    5 pages including 2 figures, to be published in PRC (Rapid Communication)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1804.08852 [pdf]
    PRC(2018)·37 citations
  4. 04

    [Submitted on 24 Apr 2018]

    Nuclear interactions and net-proton number fluctuations in heavy ion collisions at the SIS18 accelerator

    Jan Steinheimer🇩🇪 · Yongjia Wang🇨🇳 · Ayon Mukherjee🇩🇪 · Yunxiao Ye🇨🇳 · Chenchen Guo🇨🇳 · Qingfeng Li🇨🇳 · Horst Stoecker🇩🇪

    The effect of nuclear interactions on measurable net-proton number fluctuations in heavy ion collisions at the SIS18/GSI accelerator is investigated. The state of the art UrQMD model including interaction potentials is employed. It is found that the nuclear forces enhance the baryon number cumulants, as predicted from grand canonical thermodynamical models. The effect however is smeared out for proton number fluctuations due to iso-spin randomization and global baryon number conservation, which decreases the cumulant ratios. For a rapidity acceptance window larger than the effects of global baryon number conservation dominate and all cumulant ratios are significantly smaller than 1.

    Comments:
    6 pages 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1804.08936 [pdf]
    PLB(2018)·13 citations
  5. 05

    [Submitted on 24 Apr 2018]

    Neutral-current neutrino-nucleus scattering off Xe isotopes

    Pekka Pirinen🇫🇮 · Jouni Suhonen🇫🇮 · Emanuel Ydrefors🇧🇷

    Large liquid xenon detectors aiming for dark matter direct detection will soon become viable tools also for investigating neutrino physics. Information on the effects of nuclear structure in neutrino-nucleus scattering can be important in distinguishing neutrino backgrounds in such detectors. We perform calculations for differential and total cross sections of neutral-current neutrino scattering off the most abundant xenon isotopes. The nuclear structure calculations are made in the nuclear shell model for elastic scattering, and also in the quasiparticle random-phase approximation (QRPA) and microscopic quasiparticle phonon model (MQPM) for both elastic and inelastic scattering. Using suitable neutrino energy distributions, we compute estimates of total averaged cross sections for 8B solar neutrinos and supernova neutrinos.

    Comments:
    17 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1804.08995 [pdf]
    Adv.High Energy Phys.(2018)·21 citations
  6. 06

    [Submitted on 24 Apr 2018]

    Magnetic field effect on nuclear matter from skyrmion crystal model

    Mamiya Kawaguchi🇯🇵 · Yong-Liang Ma🇨🇳 · Shinya Matsuzaki🇯🇵

    We explore magnetic field effects on the nuclear matter based on the skrymion crystal approach for the first time. It is found that the magnetic effect plays the role of a catalyzer for the topological phase transition (topological deformation for the skyrmion crystal configuration from the skrymion phase to half-skyrmion phase). Furthermore, we observe that in the presence of the magnetic field, the inhomogeneous chiral condensate persists both in the skyrmion and half-skyrmion phases. Explicitly, as the strength of magnetic field gets larger, the inhomogeneous chiral condensate in the skyrmion phase tends to be drastically localized, while in the half-skyrmion phase the inhomogeneity configuration is hardly affected. It also turns out that a large magnetic effect in a low density region distorts the baryon shape to an elliptic form but the crystal structure is intact. However, in a high density region, the crystal structure is strongly effected by the strong magnetic field. A possible correlation between the chiral inhomogeneity and the deformation of the skrymion configuration is also addressed. The results obtained in this paper might be realized in the deep interior of compact stars.

    Comments:
    13 pages, 31 figures, minor corrections made, some revision made, references added
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1804.09015 [pdf]
    PRC(2018)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE