Nuclear Theory·nucl-th

Monday·December 17, 2018

8 papers—5 primary·3 cross-listed

01
[Submitted on 13 Dec 2018]
Is the unusual near-threshold potential behavior in elastic scattering of weakly bound nuclei a precision error?
Rodrigo Navarro Pérez🇺🇸 · Jin Lei🇺🇸
We present the first example of a rigorous uncertainty quantification on elastic Nucleus-Nucleus scattering at energies near the Coulomb barrier. Experimental data has been analyzed using an energy dependent effective optical model potential with physical constraints imposed. We confirm the compatibility of these uncertainties with the well known Coulomb threshold anomaly, explained in terms of a dispersive relation, and contrast our results with previous analyses that suggest otherwise.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1812.05641 [pdf]
PLB(2019)·12 citations
02
[Submitted on 13 Dec 2018]
Evolving Charge Correlations in a Hybrid Model with both Hydrodynamics and Hadronic Boltzmann Descriptions
Scott Pratt🇺🇸 · Christopher Plumberg🇸🇪
Correlations related to local charge conservation provide insight into the creation and evolution of up, down and strange charges in the quark-gluon plasma. Here, the evolution of charge correlations is overlaid onto a hydrodynamic calculation for the regions where temperature exceed 155 MeV, then transferred and carried through a microscopic model of the hadronic stage. Thus, for the first time, charge correlations are evolved consistently with a full state-of-the-art description of a heavy-ion collision. The charge correlations are projected onto charge balance functions, which characterize such correlations in the final state, and are presented as a function of relative rapidity and relative azimuthal angle for Au/Au collisions. The role of the hadronic stage is investigated. Calculation of the contribution to charge-separation observables related to the chiral magnetic effect are also presented. Calculations are compared to data from the STAR Collaboration at RHIC (Relativistic Heavy Ion Collider) data when possible.
Comments:
29 pages 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.05649 [pdf]
PRC(2019)·31 citations
03
[Submitted on 14 Dec 2018]
Bose-Einstein condensation of dilute alpha clusters above four $α$ threshold in $^{16}$ O in field theoretical superfluid cluster model
Junichi Takahashi · Yoshiya Yamanaka · Shigeru Ohkubo
Observed well-developed $α$ cluster states in $^{16}$ O, located above the four $α$ threshold, are investigated from the viewpoint of Bose-Einstein condensation of $α$ clusters by using a field-theoretical superfluid cluster model in which the order parameter is defined. The experimental energy levels are reproduced well for the first time by calculation. In particular, the observed 16.7 MeV $0_{7}^{+}$ and 18.8 MeV $0_{8}^{+}$ states with low-excitation energies from the threshold are found to be understood as a manifestation of the states of the Nambu-Goldstone zero-mode operators, associated with the spontaneous symmetry breaking of the global phase, which is caused by the Bose-Einstein condensation of the vacuum 15.1 MeV $0_{6}^{+}$ state with a dilute well-developed $α$ cluster structure just above the threshold. This gives evidence of the existence of the Bose-Einstein condensate of $α$ clusters in $^{16}$ O. It is found that the emergence of the energy level structure with a well-developed $α$ cluster structure above the threshold is robust, almost independently of the condensation rate of $α$ clusters under significant condensation rate. The finding of the mechanism why the level structure that is similar to $^{12}$ C emerges above the four $α$ threshold in $^{16}$ O reinforces the concept of Bose-Einstein condensation of $α$ clusters in addition to $^{12}$ C.
Comments:
7 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.05769 [pdf]
PTEP(2020)·1 citation
04
[Submitted on 14 Dec 2018]
Superheavy Elements: Beyond the 7th Period in the Periodic Table
K. Hagino
What is the heaviest element? In order to address this question, the elements up to $Z = 118$ have been synthesized by now by using heavy-ion fusion reactions. This has completed the 7th period in the periodic table of elements, and new attempts have been commenced in aiming at syntheses of the elements in the 8th period. In this article, we review the current status and future challenges in the research field of superheavy elements, putting some emphasis on perspectives from the nuclear reaction theory.
Comments:
9 pages, 5 figures. To be published in AAPPS Bulletin
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1812.05805 [pdf]
1 citation
05
[Submitted on 14 Dec 2018]
Estimating magnetar radii with an empirical meta-model
Debarati Chatterjee🇫🇷 · Francesca Gulminelli🇫🇷 · Debora P. Menezes🇧🇷
The presence of strong magnetic fields in neutron stars, such as in magnetars, may significantly affect their crust-core transition properties and the crust size. This knowledge is crucial in the correct interpretation of astrophysical phenomena involving magnetars, such as glitches in observed rotation frequencies, cooling, bursts and possibly tidal polarizabilities. A recently developed meta-modelling technique allows exploring the model dependence of density functional theory equation of state calculations. In this work, we extend this meta-model to investigate the effect of strong magnetic fields on spinodal instabilities of neutron star matter and the associated crust-core properties. Both Tolman-Oppenheimer-Volkov and a full self-consistent numerical calculations are performed for the neutron star structure, the results being quantitatively different for strong magnetic fields.
Comments:
24 pages, 10 figures, 9 tables, regular journal article
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1812.05879 [pdf]
JCAP(2019)·14 citations
06
[Submitted on 13 Dec 2018] (cross-list from hep-ph)
Nuclear structure factors for general spin-independent WIMP-nucleus scattering
Martin Hoferichter🇺🇸 · Philipp Klos🇩🇪 · Javier Menéndez🇯🇵 · Achim Schwenk🇩🇪
We present nuclear structure factors that describe the generalized spin-independent coupling of weakly interacting massive particles (WIMPs) to nuclei. Our results are based on state-of-the-art nuclear structure calculations using the large-scale nuclear shell model. Starting from quark- and gluon-level operators, we consider all possible coherently enhanced couplings of spin-1/2 and spin-0 WIMPs to one and two nucleons up to third order in chiral effective field theory. This includes a comprehensive discussion of the structure factors corresponding to the leading two-nucleon currents covering, for the first time, the contribution of spin-2 operators. We provide results for the most relevant nuclear targets considered in present and planned dark matter direct detection experiments: fluorine, silicon, argon, and germanium, complementing our previous work on xenon. All results are also publicly available in a Python notebook.
Comments:
24 pages, 19 figures, Python notebook available at https://theorie.ikp.physik.tu-darmstadt.de/strongint/ChiralEFT4DM.html; further details on nuclear structure added, journal version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1812.05617 [pdf]
PRD(2019)·100 citations
07
[Submitted on 14 Dec 2018] (cross-list from hep-ph)
Schwinger pair production and string breaking in non-Abelian gauge theory from real-time lattice improved Hamiltonians
D. Spitz🇩🇪 · J. Berges🇩🇪
Far-from-equilibrium dynamics of SU(2) gauge theory with Wilson fermions is studied in 1+1 space-time dimensions using a real-time lattice approach. Lattice improved Hamiltonians are shown to be very efficient in simulating Schwinger pair creation and emergent phenomena such as plasma oscillations. As a consequence, significantly smaller lattices can be employed to approach continuum physics in the infinite-volume limit as compared to unimproved implementations. This allows us to compute also higher-order correlation functions including four fermion fields, which give unprecedented insights into the real-time dynamics of the fragmentation process of strings between fermions and antifermions.
Comments:
19 pages, 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1812.05835 [pdf]
PRD(2019)·30 citations
08
[Submitted on 14 Dec 2018] (cross-list from hep-ph)
$Ω_{c}$ excited states: a molecular approach with heavy-quark spin symmetry
Laura Tolos🇩🇪 · Rafael Pavao🇪🇸 · Juan Nieves🇪🇸
The LHCb Collaboration has recently discovered five excited $Ω_{c}$ states with masses between 3 and 3.1 GeV, four of them corroborated by the Belle Collaboration. We analyse the dynamical generation of these states within a molecular baryon-meson model that is consistent with both chiral and heavy-quark spin symmetries. Earlier predictions within this model found five $Ω_{c}$ states with masses below 3 GeV. Thus, in order to study the possible identification of any of these states with the experimental ones in the correct energy region, we explore two different regularization schemes, that is, a modified regularization subtraction method and a cutoff regularization scheme. We find that at least three of the dynamically generated states can be identified with the experimental ones and have spin-parity $J = 1/ 2^{-}$ or $J = 3/ 2^{-}$
Comments:
6 pages, 3 tables, 1 figure, contribution based on a keynote parallel talk of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba (Japan)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1812.05956 [pdf]
JPS Conf.Proc.(2019)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE