Nuclear Theory·nucl-th

Tuesday·July 4, 2017

13 papers—8 primary·5 cross-listed

09
[Submitted on 30 Jun 2017] (cross-list from hep-ph)
Probing the hot and dense nuclear matter with $K^{*}, K ˉ^{*}$ vector mesons
Andrej Ilner🇩🇪 · Justin Blair🇺🇸 · Daniel Cabrera🇪🇸 · Christina Markert🇺🇸 · Elena Bratkovskaya🇩🇪
We investigate probing the hot and dense nuclear matter with strange vector mesons ( $K^{*}, K ˉ^{*}$ ). Our analysis is based on PHSD which incorporates partonic and hadronic dof and describes the full dynamics of HICs. This allows to study the $K^{*}$ and $K ˉ^{*}$ meson formation from the QGP and the in-medium effects related to the modification of their properties during the propagation in dense and hot matter. We employ relativistic Breit-Wigner spectral functions for the $K^{*}, K ˉ^{*}$ mesons with self-energies obtained from a G-matrix approach to study the role of in-medium effects on the $K^{*}$ and $K ˉ^{*}$ meson dynamics in HIC from FAIR/NICA to LHC energies. According to our analysis most of the final $K^{*} / K ˉ^{*}$ s, that can be observed experimentally, are produced during the late hadronic phase and stem dominantly from the $K (K ˉ) + π \to K^{*} (K ˉ^{*})$ formation channel. The amount of $K^{*} / K ˉ^{*}$ s originating from the QGP channel is comparatively small even at LHC energies and such $K^{*} / K ˉ^{*}$ s can hardly be reconstructed experimentally due to the rescattering of final pions and (anti-)kaons. This mirrors the results from our previous study on the strange vector-meson production in HICs at RHIC energies. The influence of the in-medium effects on the dynamics of the $K^{*} / K ˉ^{*}$ is rather small since they are mostly produced at low baryon densities. Additional cuts on the shape of the observed signal and the range of the invariant mass region of the $K^{*} / K ˉ^{*}$ also affect the final spectra. We demonstrate that the $K^{*} / K ˉ^{*}$ in-medium effects are more visible at lower beam energy, e.g. FAIR/NICA and BES RHIC energies, where the production of $K^{*} / K ˉ^{*}$ s occurs at larger baryon densities. Finally, we present the experimental procedures to extract information on the in-medium masses and widths by fitting final mass spectra at LHC energies.
Comments:
24 pages, 34 figures, extended version as published in Phys. Rev. C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.00060 [pdf]
PRC(2019)·31 citations
10
[Submitted on 1 Jul 2017] (cross-list from hep-ph)
Study of the in-medium nucleon electromagnetic form factors using a light-front nucleon wave function combined with the quark-meson coupling model
W. R. B. de Aráujo (Secretaria de Educaçao do Estado de São Paulo)🇧🇷 · J.P. B. C. de Melo🇧🇷 · K. Tsushima (Laboratório de Física Teórica e Computacional, Universidade Cruzeiro do Sul)🇧🇷
We study the nucleon electromagnetic (EM) form factors in symmetric nuclear matter as well as in vacuum within a light-front approach using the in-medium inputs calculated by the quark-meson coupling model. The same in-medium quark properties are used as those used for the study of in-medium pion properties. The zero of the proton EM form factor ratio in vacuum, the electric to magnetic form factor ratio $μ_{p} G_{E p} (Q^{2}) / G_{M p} (Q^{2})$ ( $Q^{2} = - q^{2} > 0$ with $q$ being the four-momentum transfer), is determined including the latest experimental data by implementing a hard constituent quark component in the nucleon wave function. A reasonable fit is achieved for the ratio $μ_{p} G_{E p} (Q^{2}) / G_{M p} (Q^{2})$ in vacuum, and we predict that the $Q_{0}^{2}$ value to cross the zero of the ratio to be about 15 GeV $^{2}$ . In addition the double ratio data of the proton EM form factors in $^{4}$ He and H nuclei, $[G_{E p}^{^{4} He} (Q^{2}) / G_{M p}^{^{4} He} (Q^{2})] / [G_{E p}^{^{1} H} (Q^{2}) / G_{M p}^{^{1} H} (Q^{2})]$ , extracted by the polarized ( $e, e^{'} p$ ) scattering experiment on $^{4}$ He at JLab, are well described. We also predict that the $Q_{0}^{2}$ value satisfying $μ_{p} G_{E p} (Q_{0}^{2}) / G_{M p} (Q_{0}^{2}) = 0$ in symmetric nuclear matter, shifts to a smaller value as increasing nuclear matter density, which reflects the facts that the faster falloff of $G_{E p} (Q^{2})$ as increasing $Q^{2}$ and the increase of the proton mean-square charge radius. Furthermore, we calculate the neutron EM form factor double ratio in symmetric nuclear matter for $0.1 < Q^{2} < 1.0$ GeV $^{2}$ . The result shows that the neutron double ratio is enhanced relative to that in vacuum, while for the proton it is quenched, and agrees with an existing theoretical prediction.
Comments:
39 pages, 11 figures. Revtex style. Title change, and news results added. To appear Nuclear Physics A
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1707.00168 [pdf]
NPA(2018)·14 citations
11
[Submitted on 2 Jul 2017] (cross-list from physics.chem-ph)
Addition and removal energies of circular quantum dots
Fei Yuan · Samuel J. Novario · Nathan M. Parzuchowski · Sarah Reimann · S. K. Bogner · Morten Hjorth-Jensen
We present and compare several many-body methods as applied to two-dimensional quantum dots with circular symmetry. We calculate the approximate ground state energy using a harmonic oscillator basis optimized by Hartree-Fock (HF) theory and further improve the ground state energy using two post-HF methods: in-medium similarity renormalization group (IM-SRG) and coupled cluster with singles and doubles (CCSD). With the application of quasidegenerate perturbation theory (QDPT) or the equations-of-motion (EOM) method to the results of the previous two methods, we obtain addition and removal energies as well. Our results are benchmarked against full configuration interaction (FCI) and diffusion Monte Carlo (DMC) where available. We examine the rate of convergence and perform extrapolations to the infinite basis limit using a power-law model.
Comments:
45 pages, 11 figures. v2: Prune background theory + minor fixes based on review
Subjects:
physics.chem-ph (physics.chem-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Nuclear Theory (nucl-th)
arXiv:
1707.00229 [pdf]
J.Chem.Phys.(2017)·2 citations
12
[Submitted on 3 Jul 2017] (cross-list from astro-ph.HE)
Axion Production from Landau Quantization in the Strong Magnetic Field of Magnetars
Tomoyuki Maruyama🇯🇵 · A. Baha Balantekin🇯🇵 · Myung-Ki Cheoun🇯🇵 · Toshitaka Kajino🇨🇳 · Grant J. Mathews🇺🇸
We utilize an exact quantum calculation to explore axion emission from electrons and protons in the presence of the strong magnetic field of magnetars. The axion is emitted via transitions between the Landau levels generated by the strong magnetic field. The luminosity of axions emitted by protons is shown to be much larger than that of electrons and becomes stronger with increasing matter density. Cooling by axion emission is shown to be much larger than neutrino cooling by the Urca processes. Consequently, axion emission in the crust may significantly contribute to the cooling of magnetars. In the high-density core, however, it may cause heating of the magnetar.
Comments:
14 pages, 3 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1707.00384 [pdf]
PLB(2018)·14 citations
13
[Submitted on 3 Jul 2017] (cross-list from hep-th)
Stiff phases in strongly coupled gauge theories with holographic duals
Christian Ecker🇦🇹 · Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · David Rodríguez Fernández🇪🇸 · Aleksi Vuorinen🇫🇮
According to common lore, Equations of State of field theories with gravity duals tend to be soft, with speeds of sound either below or around the conformal value of $v_{s} = 1/ 3$ . This has important consequences in particular for the physics of compact stars, where the detection of two solar mass neutron stars has been shown to require very stiff equations of state. In this paper, we show that no speed limit exists for holographic models at finite density, explicitly constructing examples where the speed of sound becomes arbitrarily close to that of light. This opens up the possibility of building hybrid stars that contain quark matter obeying a holographic equation of state in their cores.
Comments:
22 pages+appendices, 12 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1707.00521 [pdf]
JHEP(2017)·62 citations

Affiliations

first authorsco-authorsvia INSPIRE

Probing the hot and dense nuclear matter with K∗,Kˉ∗ vector mesons

Study of the in-medium nucleon electromagnetic form factors using a light-front nucleon wave function combined with the quark-meson coupling model

Addition and removal energies of circular quantum dots

Axion Production from Landau Quantization in the Strong Magnetic Field of Magnetars

Stiff phases in strongly coupled gauge theories with holographic duals

Affiliations

Probing the hot and dense nuclear matter with $K^{}, K ˉ^{}$ vector mesons