Nuclear Theory·nucl-th

Thursday·July 11, 2019

9 papers—5 primary·4 cross-listed

01
Allowed $β$ -decay spectrum with numerical electron wave functions
Dong-Liang Fang🇨🇳
Using numerical electron wave functions and state-of-the-art nuclear many-body methods, I evaluate the $β$ -decay spectra for typical decay channels of spherical nuclei. I check errors brought by various approximations used for deriving the analytical shape factors (the so-called Fermi Function) of allowed decay. I estimate the errors brought by different electric charge distributions and give a way of estimation of $β$ -spectra with available decay data of specific nuclei. I found that the traditional ways of approximating the electron wave functions by Fermi Function could be a very severe source of error for spectra simulation.
nucl-thhep-ph3 citations
02
First, second, third and fourth flow harmonics of deuterons and protons in Au+Au reactions at 1.23 A GeV
Paula Hillmann🇩🇪 · Jan Steinheimer🇩🇪 · Tom Reichert🇩🇪 · Vincent Gaebel🇩🇪 · Marcus Bleicher🇩🇪 · Sukanya Sombun🇹🇭 · Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭
We explore the directed, elliptic, triangular and quadrangular flow of deuterons in Au+Au reactions at a beam energy of 1.23 AGeV within the UrQMD approach. These investigations are of direct relevance for the HADES experiment at GSI that has recently presented first data on the flow of light clusters in Au+Au collisions at 1.23 AGeV. To address the deuteron flow, UrQMD has been extended to include deuteron formation by coalescence. We find that this ansatz provides a very good description of the measured deuteron flow data, if a hard equation of state is used for the simulation. In addition we show that light cluster formation has a sizable impact on the proton flow and has to be taken into account to obtain reliable results in the forward/backward region. Based on the observed scaling of the flow, which is a natural result of coalescence, we conclude that deuteron production at GSI energies is a final state recombination effect. Finally, we also discuss the scaling relations of the higher order flow components up to $v_{4}$ . We show that $v_{3} \sim v_{1} v_{2}$ and $v_{4} \sim v_{2}^{2}$ as function of transverse momentum and that the integrated $v_{2}^{2} \sim v_{4}$ over the investigated energy range from $E_{l ab}$ =0.1 AGeV to 40 AGeV.
nucl-thJ.Phys.G(2020)·54 citations
03
Microscopic studies of production cross sections in multinucleon transfer reaction $^{58}$ Ni+ $^{124}$ Sn
Zhenji Wu · Lu Guo
\item[Background] Multinucleon transfer reaction at low-energy collisions is considered to be a promising method for the production of new exotic nuclei, which are difficult to be produced by other methods. The theoretical studies are required to provide reliable predictions for the experiments and promote the understanding of the microscopic mechanism in multinucleon transfer reactions. \item[Purpose] We provide a predictive approach for production cross sections, and testify how and to what extent the microscopic approach works well in multinucleon transfer reaction. \item[Methods] We employ the approach TDHF+GEMINI, which combines the microscopic time-dependent Hartree-Fock (TDHF) with the state-of-art statistical model GEMINI++, to take into account both the multinucleon transfer dynamics and the secondary deexcitation process. The properties of primary products in multinucleon transfer process, such as transfer probabilities and primary cross sections, are extracted from TDHF dynamics by using the particle-number projection method. Production cross sections for secondary products are evaluated by using the statistical model GEMINI++. \item[Results] We investigate the influence of colliding energies and deformation orientations of target and projectile nuclei on multinucleon transfer dynamics in the reaction $^{58}$ Ni+ $^{124}$ Sn...... \item[Conclusions] The microscopic approach TDHF+GEMINI reasonably reproduces the experimental data at energies close to the Coulomb barrier and well accounts for the multinucleon transfer mechanism. The present studies clearly reveal the applicability of TDHF+GEMINI method in multinucleon transfer reactions, which thus deserves as a promising tool to predict the properties of new reactions.
nucl-thnucl-exPRC(2019)·73 citations
04
Effect of Octupole correlations on Fission of Light Nuclei
Guillaume Scamps · Cédric Simenel
Fission of $^{180}$ Hg produces mass asymmetric fragments which are expected to be influenced by deformed shell-effects at N=56 in the heavy fragment and Z=34 in the light fragment [G. Scamps and C. Simenel, arXiv:1904.01275 (2019)]. To investigate both shell-effects and to determine which one has the main influence on the asymmetry in the region of the $^{180}$ Hg, we produce a systematic of Constraint-Hartree-Fock calculations in nuclei with similar N/Z ratio than the $^{178}$ Pt. It is found that N=56 determines the asymmetry of systems in this region of the nuclear chart.
nucl-thnucl-exJPS Conf.Proc.(2020)·0 citations
05
Coulomb Energy Density Functionals for Nuclear Systems: Recent Studies of Coulomb Exchange and Correlation Functionals
Tomoya Naito · Ryosuke Akashi · Gianluca Colò · Haozhao Liang · Xavier Roca-Maza
The Coulomb exchange and correlation energy density functionals for electron systems are applied to nuclear systems. It is found that the exchange functionals in the generalized gradient approximation provide agreements with the exact-Fock energy with one adjustable parameter within a few dozen $keV$ accuracy, whereas the correlation functionals are not directly applicable to nuclear systems due to the existence of the nuclear force.
nucl-thnucl-exEPJ Web Conf.(2019)·0 citations
06
Toward an effective theory of quarkonium production in nuclear matter
Ivan Vitev🇺🇸
These proceedings are dedicated to Miklos Gyulassy's 70 $^{th}$ birthday. In his long and distinguished career he has made seminal contributions to many areas of heavy ion theory, including early papers on quarkonium phenomenology in fixed-target heavy ion experiments. Theoretical and experimental studies of the $J / ψ$ and $Υ$ states have evolved considerably in the past decades, and I describe a recent generalization of non-relativistic Quantum Chromodynamics to include interactions in a generic nuclear medium. NRQCD with Glauber gluons aims to provide a universal microscopic description of the interaction of heavy quarkonia in a range of phases that include cold nuclear matter, dense hadron gas, and quark-gluon plasma. Such effective field theory is an important step toward understanding the common trends in proton-nucleus and nucleus-nucleus data on quarkonium suppression.
↳ hep-phnucl-thPoS(2020)·1 citation
07
Hyperon production in $Λ_{c}^{+} \to K^{-} p π^{+}$ and $Λ_{c}^{+} \to K_{S}^{0} p π^{0}$
Jung Keun Ahn🇰🇷 · Seongbae Yang🇰🇷 · Seung-il Nam🇰🇷
We investigate $S = - 1$ hyperon production from the $Λ_{c}^{+} \to K^{-} p π^{+}$ and $Λ_{c}^{+} \to K_{S}^{0} p π^{0}$ decays within the effective Lagrangian approach. We consider the $Σ/Λ$ ground states, $Λ (1520)$ , $Λ (1670) (J^{p} = 1/ 2^{-})$ , $Λ (1890) (J^{p} = 3/ 2^{+})$ ; $Λ/Σ$ -pole contributions from the combined resonances between 1800 MeV and 2100 MeV; and $N /Δ$ -pole and $K^{*}$ -pole contributions, which include the proton, $Δ (1232)$ , and $K (892)$ . We calculate the Dalitz plot density $(d^{2} Γ/ d M_{K^{-} p} d M_{K^{-} π^{+}}$ ) for the $Λ_{c}^{+} \to K^{-} p π^{+}$ decay. The calculated result is in good agreement with experimental data from the Belle Collaboration. Using the parameters from the fit, we present the Dalitz plot density for the $Λ_{c}^{+} \to K_{S}^{0} p π^{0}$ decay. In our calculation, a sharp peak-like structure near 1665 MeV is predicted in the $Λ_{c}^{+} \to K^{-} p π^{+}$ decay because of the interference effects between the $Λ (1670)$ resonance and $η$ - $Λ$ loop channels. We also demonstrate that we can access direct information regarding the weak couplings of $Λ (1670)$ and $Σ (1670)$ from the $Λ_{c}^{+} \to K_{S}^{0} p π^{0}$ decay. Finally, a possible interpretation for the 1665 MeV structure beyond our prediction is briefly discussed.
↳ hep-phhep-exnucl-exnucl-thPRD(2019)·11 citations
08
Masses of ground and isomeric states of $^{101}$ In and configuration-dependent shell evolution in odd- $A$ indium isotopes
X. Xu🇨🇳 · J. H. Liu🇨🇳 · C. X. Yuan🇨🇳 · Y. M. Xing🇨🇳 · M. Wang🇨🇳 · Y. H. Zhang🇨🇳 · X. H. Zhou🇨🇳 · Yu. A. Litvinov🇨🇳 · K. Blaum🇩🇪 · R. J. Chen🇨🇳 · X. C. Chen🇨🇳 · C. Y. Fu🇨🇳 and 31 other authors
We report first precision mass measurements of the $1/ 2^{-}$ isomeric and $9/ 2^{+}$ ground states of $^{101}$ In. The determined isomeric excitation energy continues a smooth trend of odd- $A$ indium isotopes up to the immediate vicinity of $N = 50$ magic number. This trend can be confirmed by dedicated shell model calculations only if the neutron configuration mixing is considered. We find that the single particle energies are different for different states of the same isotope. The presented configuration-dependent shell evolution, type II shell evolution, in odd- $A$ nuclei is discussed for the first time. Our results will facilitate future studies of single-particle neutron states.
↳ nucl-exnucl-thPRC(2019)·21 citations
09
Phase transitions in neutron stars and their links to gravitational waves
Milva G. Orsaria🇦🇷 · Germán Malfatti🇦🇷 · Mauro Mariani🇦🇷 · Ignacio F. Ranea-Sandoval🇦🇷 · Federico García🇫🇷 · William M. Spinella🇺🇸 · Gustavo A. Contrera🇦🇷 · Germán Lugones🇧🇷 · Fridolin Weber🇺🇸
The recent direct observation of gravitational wave event $G W 170817$ and its $GR B 170817 A$ signal has opened up a new window to study neutron stars and heralds a new era of Astronomy referred to as the Multimessenger Astronomy. Both gravitational and electromagnetic waves from a single astrophysical source have been detected for the first time. This combined detection offers an unprecedented opportunity to place constraints on the neutron star matter equation of state. The existence of a possible hadron-quark phase transition in the central regions of neutron stars is associated with the appearance of g-modes, which are extremely important as they could signal the presence of a pure quark matter core in the centers of neutron stars. Observations of g-modes with frequencies between 1 kHz and 1.5 kHz could be interpreted as evidence of a sharp hadron-quark phase transition in the cores of neutron stars. In this article, we shall review the description of the dense matter composing neutron stars, the determination of the equation of state of such matter, and the constraints imposed by astrophysical observations of these fascinating compact objects.
↳ astro-ph.HEhep-phnucl-thJ.Phys.G(2019)·75 citations

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