Nuclear Theory·nucl-th

Tuesday·March 22, 2016

11 papers—7 primary·4 cross-listed

01
[Submitted on 19 Mar 2016]
Positron production in collision of heavy nuclei
I.B. Khriplovich🇷🇺 · D.A. Solovyev🇷🇺
We consider the electromagnetic production of positron in collision of heavy nuclei, with the simultaneously produced electron captured by one of the nuclei. This cross-section exceeds by about four orders of magnitude the cross-section of $e^{+} e^{-}$ production.
Comments:
3 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Atomic Physics (physics.atom-ph)
arXiv:
1603.06061 [pdf]
1 citation
02
[Submitted on 19 Mar 2016]
Vorticity in Heavy-Ion Collisions
Wei-Tian Deng · Xu-Guang Huang
We study the event-by-event generation of flow vorticity in RHIC Au + Au collisions and LHC Pb + Pb collisions by using the HIJING model. Different definitions of the vorticity field and velocity field are considered. A variety of properties of the vorticity are explored, including the impact parameter dependence, the collision energy dependence, the spatial distribution, the event-by-event fluctuation of the magnitude and azimuthal direction, and the time evolution. In addition, the spatial distribution of the flow helicity is also studied.
Comments:
V2: 31 pages, 16 figures; new discussion added to the end of Sec.VI, references updated
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1603.06117 [pdf]
PRC(2016)·241 citations
03
[Submitted on 20 Mar 2016]
Solution of Faddeev integral equations in configuration space using the hyperspherical harmonics expansion method
V.I.Kovalchuk
A method has been developed to solve three-particle Faddeev equations in the configuration space making use of a series expansion in hyperspherical harmonics. The following parameters of the bound state of triton and helium-3 nuclei have been calculated: the binding energies, the weights of symmetric and mixed-symmetry components of the wave function, the magnetic moments, and the charge radii.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1603.06275 [pdf]
IJMPE(2014)·1 citation
04
[Submitted on 21 Mar 2016]
Anomalous Hyperfine Structure of the $^{229}$ Th Ground-State Doublet in Muonic Atom
E. V. Tkalya
The hyperfine splitting of the ground and low-energy $3/ 2^{+} (7.8 \pm 0.5$ eV) levels in the $^{229}$ Th nucleus in muonic atom ( $μ_{1 S_{1/2}}^{-}^{229}$ Th $)^{*}$ has been calculated considering the distribution of the nuclear magnetization in the framework of collective nuclear model with the wave functions of the Nilsson model for the unpaired neutron. It is shown that (a) the hyperfine splitting of the $3/ 2^{+}$ isomeric state is anomalously weak, and the reduction of hyperfine structure in comparison with the model of a point nuclear magnetic dipole is close to 100\%, (b) partial inversion of levels of the $^{229}$ Th ground-state doublet and spontaneous decay of the ground state with excitation of the isomeric state take place, (c) the energy of the isomeric transition lies in the range of 120--140 eV, which makes possible the direct observation of the transition, registration of conversion electrons and measurement of the nuclear matrix element.
Comments:
5 pages, 3 figures, 1 table
Subjects:
Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
arXiv:
1603.06343 [pdf]
PRA(2016)·13 citations
05
[Submitted on 21 Mar 2016]
Thermal Conductivity Coefficient from Microscopic Models
T.E Nemakhavhani🇿🇦 · A. Muronga🇿🇦
Thermal conductivity of hadron matter is studied using a microscopic transport model, which will be used to simulate ultra-relativistic heavy ion collisions at different energy densities, namely the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). The molecular dynamics simulation is performed for a system of light mesons species (pion, rho, kaon) in a box with periodic boundary conditions. The equilibrium state is investigated by studying chemical equilibrium and thermal equilibrium of the system. Particle multiplicity equilibrates with time, and the energy spectra of different light mesons species have the same slopes and common temperatures when thermal equilibrium is reached. Thermal conductivity transport coefficient is calculated from the heat current - current correlations using the Green-Kubo relations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1603.06347 [pdf]
0 citations
06
[Submitted on 21 Mar 2016]
Blast-wave model description of the HBT radii measured in $pp$ collisions at the LHC energies
Wojciech Florkowski🇵🇱
Blast-wave model is applied to describe the Hanbury-Brown--Twiss (HBT) radii of pionic systems produced in pp collisions at the LHC energies.
Comments:
Talk presented at the XI Workshop on Particle Correlations and Femtoscopy, dedicated to Professor Jan Pluta on the occasion of his 70th birthday
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1603.06418 [pdf]
Acta Phys.Polon.B(2016)·4 citations
07
[Submitted on 21 Mar 2016]
Foundations of Strangeness Nuclear Physics derived from chiral Effective Field Theory
Ulf-G. Meißner🇩🇪 · Johann Haidenbauer🇩🇪
Dense compact objects like neutron stars or black holes have always been one of Gerry Brown's favorite research topics. This is closely related to the effects of strangeness in nuclear physics. Here, we review the chiral Effective Field Theory approach to interactions involving nucleons and hyperons, the possible existence of strange dibaryons, the fate of hyperons in nuclear matter and the present status of three-body forces involving hyperons and nucleons.
Comments:
20 pages, chapter for the memorial book "Gerry Brown 90"
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1603.06429 [pdf]
IJMPE(2017)·5 citations
08
[Submitted on 21 Mar 2016] (cross-list from hep-ph)
How the X(5568) challenges our understanding of QCD
Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇨🇳 · Bing-Song Zou🇨🇳
We discuss the X(5568) particle recently announced by the D0 Collaboration. Several types of models were proposed to explain this structure in the literature. As pointed out by Burns and Swanson (arXiv:1603.04366), none of them provides a satisfactory description of the observation. We provide additional arguments using general properties of QCD, and conclude that the observation of the X(5568), if confirmed, poses serious challenges to our understanding of nonperturbative QCD.
Comments:
5 pages. Typos removed, a wrong statement corrected, conclusions unchanged; the LHCb preliminary result mentioned at the end
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1603.06316 [pdf]
Commun.Theor.Phys.(2016)·75 citations
09
[Submitted on 21 Mar 2016] (cross-list from astro-ph.HE)
Spectral splits of neutrinos as a BCS-BEC crossover type phenomenon
Y. Pehlivan🇹🇷 · A. L. Subaşı🇹🇷 · N. Ghazanfari🇹🇷 · S. Birol🇹🇷 · H. Yüksel🇹🇷
We show that the spectral split of a neutrino ensemble which initially consists of electron type neutrinos, is analogous to the BCS-BEC crossover already observed in ultra cold atomic gas experiments. Such a neutrino ensemble mimics the deleptonization burst of a core collapse supernova. Although these two phenomena belong to very different domains of physics, the propagation of neutrinos from highly interacting inner regions of the supernova to the vacuum is reminiscent of the evolution of Cooper pairs between weak and strong interaction regimes during the crossover. The Hamiltonians and the corresponding many-body states undergo very similar transformations if one replaces the pair quasispin of the latter with the neutrino isospin of the former.
Comments:
9 pages, 5 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1603.06360 [pdf]
PRD(2017)·19 citations
10
[Submitted on 21 Mar 2016] (cross-list from hep-ph)
Masses of open charm and bottom tetraquark states in a relativized quark model
Qi-Fang Lü🇨🇳 · Yu-Bing Dong🇨🇳
We study the masses of open charm and bottom tetraquark states within the diquark-antidiquark scenario in the relativized quark model proposed by Godfrey and Isgur. The diquark and antidiquark masses are firstly solved by relativized quark potential, and then treated as the usual antiquark and quark, respectively. The masses of tetraquark states are obtained by solving the Schrödinger-type equation between the new diquark and antidiquark. We find the masses of $s q b ˉ q ˉ$ tetraquark configuration are much higher than that of $X (5568)$ . This conclusion disfavors the possibility of $X (5568)$ as a tetraquark state within the diquark-antidiquark scenario. Further experimental searches are needed to clarify the nature of the signal observed by D0 collaboration.
Comments:
5 pages, 1 figure, 2 tables. Version accepted by Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1603.06417 [pdf]
PRD(2016)·52 citations
11
[Submitted on 21 Mar 2016] (cross-list from hep-ph)
Universal Strangeness Production in Hadronic and Nuclear Collisions
P.Castorina🇮🇹 · S.Plumari🇮🇹 · H.Satz🇩🇪
We show that strangeness suppression in hadronic and nuclear collisions is fully determined by the initial energy density of the collision. The suppression factor $γ_{s} (s)$ , with $s$ denoting the collision energy, can be expressed as a universal function of the initial energy density $ϵ_{0} (s)$ , and the resulting pattern is in excellent agreement with data from $p - p, p - P b, C u - C u, A u - A u$ and $P b - P b$ data over a wide range of energies and for different centralities.
Comments:
more general formulation
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1603.06529 [pdf]
IJMPE(2016)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE