Nuclear Theory·nucl-th

Thursday·January 8, 2015

7 papers—3 primary·4 cross-listed

01
Half-lives of Double $β^{+}$ -decay with Two Neutrinos
Yuejiao Ren🇨🇳 · Zhongzhou Ren🇨🇳
Nuclear double $β^{-}$ -decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently [Phys. Rev. C89, 064603 (2014)]. However, double $β^{+}$ -decay ( $β^{+} β^{+})$ with emission of both two positrons and two neutrinos has not been observed up to date. In this article, we perform a systematic analysis on the candidates of double $β^{+}$ -decay, based on the 2012 nuclear mass table. Eight nuclei are found to be the good candidates for double $β^{+}$ -decay and their half-lives are predicted according to the generalization of the systematic law to double $β^{+}$ -decay. As far as we know, there is no theoretical result on double $β^{+}$ -decay of nucleus $^{154} D y$ and our result is the first prediction on this nucleus. This is also the first complete research on eight double $β^{+}$ -decay candidates based on the available data of nuclear masses. It is expected that the calculated half-lives of double $β^{+}$ -decay in this article will be useful for future experimental search of double $β^{+}$ -decay.
nucl-thSCPMA(2015)·5 citations
02
A new shock-capturing numerical scheme for ideal hydrodynamics
Zuzana Feckova · Boris Tomasik
We present a new algorithm for solving ideal relativistic hydrodynamics based on Godunov method with an exact solution of Riemann problem for an arbitrary equation of state. Standard numerical tests are executed, such as the sound wave propagation and the shock tube problem. Low numerical viscosity and high precision are attained with proper discretization.
nucl-thJ.Phys.Conf.Ser.(2015)·0 citations
03
De-Confinement and Clustering of Color Sources in Nuclear Collisions
M. A. Braun🇷🇺 · J. Dias de Deus🇵🇹 · A. S. Hirsch🇺🇸 · C. Pajares🇪🇸 · R. P. Scharenberg🇺🇸 · B. K. Srivastava🇺🇸
A brief introduction of the relationship of string percolation to the Quantum Chromo Dynamics (QCD) phase diagram is presented. The behavior of the Polyakov loop close to the critical temperature is studied in terms of the color fields inside the clusters of overlapping strings, which are produced in high energy hadronic collisions. The non-Abelian nature of the color fields implies an enhancement of the transverse momentum and a suppression of the multiplicities relative to the non overlapping case. The prediction of this framework are compared with experimental results from the SPS, RHIC and LHC for $pp$ and AA collisions. Rapidity distributions, probability distributions of transverse momentum and multiplicities, Bose-Einstein correlations, elliptic flow and ridge structures are used to evaluate these comparison. The thermodynamical quantities, the temperature, and energy density derived from RHIC and LHC data and Color String Percolation Model (CSPM) are used to obtain the shear viscosity to entropy density ratio ( $η / s$ ). It was observed that the inverse of ( $η / s$ ) represents the trace anomaly $Δ = (ε - 3 P) / T^{4}$ . Thus the percolation approach within CSPM can be successfully used to describe the initial stages in high energy heavy ion collisions in the soft region in high energy heavy ion collisions. The thermodynamical quantities, temperature and the equation of state are in agreement with the lattice QCD calculations. Thus the clustering of color sources has a clear physical basis although it cannot be deduced directly from QCD.
nucl-thhep-phnucl-exPhys.Rept.(2015)·84 citations
04
Topology, magnetic field, and strongly interacting matter
Dmitri E. Kharzeev🇺🇸
Gauge theories with compact symmetry groups possess topologically non-trivial configurations of gauge field. This has dramatic implications for the vacuum structure of Quantum Chromo-Dynamics (QCD) and for the behavior of QCD plasma, as well as for condensed matter systems with chiral quasiparticles. I review the current status of the problem with an emphasis on the interplay of chirality with a background magnetic field, and on the observable manifestations of topology in heavy ion collisions, Dirac semimetals, neutron stars, and in the Early Universe.
↳ hep-phhep-thnucl-thAnn.Rev.Nucl.Part.Sci.(2015)·97 citations
05
On Fermionic Shadow Wave Functions for strongly-correlated multi-reference systems based on a single Slater determinant
F. Calcavecchia · T. D. Kühne
We demonstrate that extending the Shadow Wave Function to fermionic systems facilitates to accurately calculate strongly-correlated multi-reference systems such as the stretched H2 molecule. This development considerably extends the scope of electronic structure calculations and enables to efficiently recover the static correlation energy using just a single Slater determinant.
↳ physics.comp-phcond-mat.str-elnucl-thphysics.chem-ph+1EPL(2015)·4 citations
06
Predicting the production of neutron rich heavy nuclei in multi-nucleon transfer reactions using GRAZING-F
R. Yanez · W. Loveland
Background: Multi-nucleon transfer reactions have recently attracted attention as a possible path to the synthesis of new neutron-rich heavy nuclei. Purpose: We study transfer reactions involving massive nuclei with the intention of understanding if the semi-classical model GRAZING coupled to an evaporation and fission competition model can satisfactory reproduce experimental data on transfer reactions in which fission plays a role. Methods: We have taken the computer code GRAZING and have added fission competition to it (GRAZING-F) using our current understanding of $Γ_{n} / Γ_{f}$ , fission barriers and level densities. Results: The code GRAZING-F seems to satisfactory reproduce experimental data for $+ 1 p$ , $+ 2 p$ and $+ 3 p$ transfers, but has limitations in reproducing measurements of larger above-target and below-target transfers. Nonetheless, we use GRAZING-F to estimate production rates of neutron-rich $N = 126$ nuclei, actinides and transactinides. Conclusions: The GRAZING code, with appropriate modifications to account for fission decay as well as neutron emission by excited primary fragments, does not predict large cross sections for multi-nucleon transfer reactions leading to neutron-rich transactinide nuclei, but predicts opportunities to produce new neutron-rich actinide isotopes.
↳ nucl-exnucl-thPRC(2015)·83 citations
07
Mott-Anderson freeze-out and the strange matter "horn"
M. Naskret🇨🇭 · D. Blaschke🇵🇱 · A. Dubinin🇵🇱
We discuss the $s$ -dependence of the $K^{+} / π^{+}$ ratio in heavy-ion collisions (the "horn" effect) within a Mott-Anderson localization model for chemical freeze-out. The different response of pion and kaon radii to the hot and dense hadronic medium results in different freeze-out conditions. We demonstrate within a simple model that this circumstance enhances the "horn" effect relative to statistical models with universal chemical freeze-out.
↳ hep-phnucl-thPhys.Part.Nucl.(2015)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Half-lives of Double β+-decay with Two Neutrinos

A new shock-capturing numerical scheme for ideal hydrodynamics

De-Confinement and Clustering of Color Sources in Nuclear Collisions

Topology, magnetic field, and strongly interacting matter

On Fermionic Shadow Wave Functions for strongly-correlated multi-reference systems based on a single Slater determinant

Predicting the production of neutron rich heavy nuclei in multi-nucleon transfer reactions using GRAZING-F

Mott-Anderson freeze-out and the strange matter "horn"

Affiliations

Half-lives of Double $β^{+}$ -decay with Two Neutrinos