Nuclear Theory·nucl-th

Wednesday·July 6, 2016

8 papers—7 primary·1 cross-listed

01
[Submitted on 5 Jul 2016]
Approach to Chandrasekhar-Kendall-Woltjer State in a Chiral Plasma
Xiao-liang Xia🇨🇳 · Hong Qin🇨🇳 · Qun Wang🇨🇳
We study the time evolution of the magnetic field in a plasma with a chiral magnetic current. The Vector Spherical Harmonic functions (VSH) are used to expand all fields. We define a measure for the Chandrasekhar-Kendall-Woltjer (CKW) state, which has a simple form in VSH expansion. We propose the conditions for a general class of initial momentum spectra that will evolve into the CKW state. For this class of initial conditions, to approach the CKW state, (i) a non-vanishing chiral magnetic conductivity is necessary, and (ii) the time integration of the product of the electric resistivity and chiral magnetic conductivity must grow faster than the time integration of the resistivity. We give a few examples to test these conditions numerically which work very well.
Comments:
RevTex 4, 15 pages, 6 figures. Typos in paragraph 1 and 2 in the introduction of the published version are corrected. These typos have no effects on the result of the paper. The typos in paragraph 2 are in Eq. (1) and in the inline formula in the second to last line
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.01126 [pdf]
PRD(2016)·24 citations
02
[Submitted on 5 Jul 2016]
Impact of low-energy nuclear excitations on neutrino-nucleus scattering at MiniBooNE and T2K kinematics
V. Pandey🇧🇪 · N. Jachowicz🇧🇪 · M. Martini🇧🇪 · R. González-Jiménez🇧🇪 · J. Ryckebusch🇧🇪 · T. Van Cuyck🇧🇪 · N. Van Dessel🇧🇪
[Background] Meticulous modeling of neutrino-nucleus interactions is essential to achieve the unprecedented precision goals of present and future accelerator-based neutrino-oscillation experiments. [Purpose] Confront our calculations of charged-current quasielastic cross section with the measurements of MiniBooNE and T2K, and to quantitatively investigate the role of nuclear-structure effects, in particular, low-energy nuclear excitations in forward muon scattering. [Method] The model takes the mean-field (MF) approach as the starting point, and solves Hartree-Fock (HF) equations using a Skyrme (SkE2) nucleon-nucleon interaction. Long-range nuclear correlations are taken into account by means of the continuum random-phase approximation (CRPA) framework. [Results] We present our calculations on flux-folded double differential, and flux-unfolded total cross sections off $^{12}$ C and compare them with MiniBooNE and (off-axis) T2K measurements. We discuss the importance of low-energy nuclear excitations for the forward bins. [Conclusions] The CRPA predictions describe the gross features of the measured cross sections. They underpredict the data (more in the neutrino than in the antineutrino case) because of the absence of processes beyond pure quasielastic scattering in our model. At very forward muon scattering, low-energy nuclear excitations ( $ω <$ 50 MeV) account for nearly 50% of the flux-folded cross section.
Comments:
8 pages, 9 figures. Version published in Physical Review C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1607.01216 [pdf]
PRC(2016)·59 citations
03
[Submitted on 30 Jun 2016]
Axiomatic nonextensive statistics at NICA energies
Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo, NNS-ASRT, Cairo)
We discuss the possibility of implementing axiomatic nonextensive statistics, where it is conjectured that the phase-space volume determines the (non)extensive entropy, on the particle production at NICA energies. Both Boltzmann-Gibbs and Tsallis statistics are very special cases of this generic (non)extensivity. We conclude that the lattice thermodynamics is {\it ab initio} extensive and additive and thus the nonextensive approaches including Tsallis statistics categorically are not matching with them, while the particle production, for instance the particle ratios at various center-of-mass energies, is likely a nonextensive process but certainly not of Tsallis type. The resulting freezeout parameters, the temperature and the chemical potentials, are approximately compatible with the ones deduced from Boltzmann-Gibbs statistics.
Comments:
6 pages, 2 figures, accepted for publication in EPJA Topical Issue "NICA White Paper" (17th Feb. 2016)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.01264 [pdf]
EPJA(2016)·15 citations
04
[Submitted on 5 Jul 2016]
Shell model studies of competing mechanisms to the neutrinoless double-beta decay in $^{124}$ Sn, $^{130}$ Te, and $^{136}$ Xe
Andrei Neacsu🇺🇸 · Mihai Horoi🇺🇸
Neutrinoless double-beta decay is a predicted beyond Standard Model process that could clarify some of the not yet known neutrino properties, such as the mass scale, the mass hierarchy, and its nature as a Dirac or Majorana fermion. Should this transition be observed, there are still challenges in understanding the underlying contributing mechanisms. We perform a detailed shell model investigation of several beyond Standard Model mechanisms that consider the existence of right-handed currents. Our analysis presents different venues that can be used to identify the dominant mechanisms for nuclei of experimental interest in the mass A $\sim$ 130 region ( $^{124}$ Sn, $^{130}$ Te, and $^{136}$ Xe). It requires an accurate knowledge of nine nuclear matrix elements that we calculate, in addition to the associated energy dependent phase-space factors.
Comments:
7 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1607.01295 [pdf]
Adv.High Energy Phys.(2016)·9 citations
05
[Submitted on 4 Jul 2016]
Has the QCD critical point been observed at RHIC?
N.G. Antoniou🇬🇷 · N. Davis🇬🇷 · F.K. Diakonos🇬🇷
The experimental search for the location of the QCD critical point in the phase diagram is of primary importance. In a recent publication it is claimed that measurements at RHIC lead not only to the location of the critical point ( $μ_{ce p} = 95$ MeV, $T_{ce p} = 165$ MeV) but also to the verification of its universality class ( $3 d$ Ising system) by extracting the values of the critical exponents ( $γ = 1.2$ , $ν = 0.66$ ). We argue that this claim is based on an erroneous treatment of scaling relations near the critical point. As a result, the correct interpretation of the measurements cannot be linked to the QCD critical point.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1607.01326 [pdf]
5 citations
06
[Submitted on 5 Jul 2016]
Electrical conductivity of hadronic matter from different possible mesonic and baryonic thermal fluctuations
Sabyasachi Ghosh🇮🇳
Electromagnetic current-current correlators in pionic and nucleonic medium have been evaluated in the static limit to obtain electrical conductivities for pion and nucleon components respectively, where former decreases and latter one increases with the variation of temperature $T$ and baryon chemical potential $μ_{N}$ . Therefore, total electrical conductivity of pion and nucleon system exhibits a valley structure in the $T$ - $μ_{N}$ plane. To get non-divergent and finite values of correlators, finite thermal widths of medium constituents, pion and nucleon have been considered, where these thermal widths have been determined from the in-medium scattering probabilities of pion and nucleon with other mesonic and baryonic resonances, based on effective hadronic model. At $μ_{N} = 0$ , the results of present work are more or less agrees with the results of earlier works and its finite $μ_{N}$ extension show a decreasing nature of electrical conductivity for hadronic medium during spanning from freeze out line to quark-hadron transition line in $T$ - $μ_{N}$ plane.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1607.01340 [pdf]
PRD(2017)·37 citations
07
[Submitted on 5 Jul 2016]
Clustering and pasta phases in nuclear density functional theory
Bastian Schuetrumpf · Chunli Zhang · Witold Nazarewicz
Nuclear density functional theory (DFT) is the tool of choice in describing properties of complex nuclei and intricate phases of bulk nucleonic matter. It is a microscopic approach based on an energy density functional representing the nuclear interaction. An attractive feature of nuclear DFT is that it can be applied to both finite nuclei and pasta phases appearing in the inner crust of neutron stars. While nuclear pasta clusters in a neutron star can be easily characterized through their density distributions, the level of clustering of nucleons in a nucleus can often be difficult to assess. To this end, we use the concept of nucleonic localization. We demonstrate that the localization measure provides us with fingerprints of clusters in light and heavy nuclei, including fissioning systems. Furthermore we investigate the rod-like pasta phase using twist-averaged boundary conditions, which enable calculations in finite volumes accessible by state of the art DFT solvers.
Comments:
19 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.01372 [pdf]
5 citations
08
[Submitted on 5 Jul 2016] (cross-list from hep-ph)
Light-cone sum rule approach for Baryon form factors
Nils Offen🇩🇪
We present the state-of-the-art of the light-cone sum rule approach to Baryon form factors. The essence of this approach is that soft Feynman contributions are calculated in terms of small transverse distance quantities using dispersion relations and duality. The form factors are thus expressed in terms of nucleon wave functions at small transverse separations, called distribution amplitudes, without any additional parameters. The distribution amplitudes, therefore, can be extracted from the comparison with the experimental data on form factors and compared to the results of lattice QCD simulations.
Comments:
8 pages,7 figures accepted for publication in "Few-Body Systems" special issue "Nucleon Resonances"
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01227 [pdf]
Few Body Syst.(2016)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE