Nuclear Theory·nucl-th

Wednesday·September 23, 2015

11 papers—6 primary·5 cross-listed

01
Photoproduction of the $f_{2}^{'} (1525)$ and $K_{2}^{*} (1430)$
Ju-Jun Xie🇨🇳 · Eulogio Oset🇨🇳 · Li-Sheng Geng🇨🇳
Assuming that the $f_{2}^{'} (1525)$ and $K_{2}^{*} (1430)$ resonances are dynamically generated states from the vector meson-vector meson interactions in $S$ -wave with spin $S = 2$ , we study the $γ p \to f_{2}^{'} (1525) p$ and $γ p \to K_{2}^{*} (1430) Λ (Σ)$ reactions. These reactions proceed in the following way: the incoming photon first mutates into a $ρ^{0}$ , $ω$ , or $ϕ$ meson via vector meson dominance, which then interacts with the $ρ^{0}$ , $ω$ or $K^{*}$ emitted by the incoming proton to form the tensor mesons $f_{2}^{'} (1525)$ and $K_{2}^{*} (1430)$ . The picture is simple and has no free parameters, as all the parameters of the mechanism have been fixed in previous studies. We predict the differential and total cross sections of these reactions. The results can be tested in future experiments and therefore offer new clues on the nature of these tensor states.
nucl-thhep-exhep-phnucl-exPRC(2016)·17 citations
02
Properties of light (anti)nuclei and (anti) hypertriton production in Pb-Pb collisions at $s_{NN}$ = 2.76 TeV
Zhi-Lei She · Gang Chen🇨🇳 · Hong-ge Xu · Ting-ting Zeng · Di-Kai Li
We investigate the properties of light (anti)nuclei and (anti)hypertriton production in Pb-Pb collisions at $s_{NN} = 2.76$ TeV, based on the parton and hadron cascade and dynamically constrained phase-space coalescence (PACIAE + DCPC) model. We found that the yields of light (anti)nuclei and (anti)hypertriton strongly depend on the centrality, i.e., their yields decrease rapidly with the increase of centrality bins, but their yield ratios are independent of centrality. The results of theoretical model are well consistent with ALICE data. Furthermore, we found that the integrated yields of (anti)nuclei per participant nucleon increase from peripheral to central collisions more rapidly with increasing mass number. The transverse momentum distributions of $_{Λ}^{3} H,_{Λ}^{3} H,^{3} H e$ and $^{3} H e$ are also discussed in the 0-10% most central Pb-Pb collisions.The coalescence parameters $B_{A}$ of light (anti)nuclei and (anti)hypernuclei are analyzed.
nucl-thhep-phEPJA(2016)·19 citations
03
Approximate solution of the pairing Hamiltonian in the Berggren basis
A. Mercenne🇫🇷 · N. Michel🇫🇷 · M. Ploszajczak🇫🇷
We derive the approximate solution for the pairing Hamiltonian in the Berggren ensemble of single particle states including bound, resonance and non-resonant scattering states. We show that this solution is reliable in the limit of a weak pairing interaction.
nucl-thActa Phys.Polon.B(2016)·1 citation
04
Common Approaches in Description of Ordinary Liquids and Hadronic Matter
K. V. Cherevko🇺🇦 · L.L. Jenkovszky🇺🇦 · V. M. Sysoev🇺🇦 · Feng-Shou Zhang🇨🇳
This work is an attempt to give a brief overview of the implementation of the statistical ther- modynamics to hadronic matter. The possibility to use the hydrodynamic approach for developing the physical model of the formation of exotic structures in the head-on intermediate-energy heavy ion collisions is discussed. That approach is shown to be able to provide simple analytical expressions describing each step of the collision process. This allows for extracting the data concerning nuclear matter properties (surface tension, compressibility, etc.) from the properties of observed fragments. The advantages of the thermodynamic analysis of phase trajectories of the system in heavy ion collisions are discussed. Within the thermodynamic approach, the method to evaluate the curvature correction to the surface tension from the nuclear matter equation of state is described. The possibility to use statistical thermodynamics in the studies of hadronic matter and quantum liquids is discussed.
nucl-thUkr. J. Phys. 2015, Vol. 60, N 8, p.708-7…·0 citations
05
Pseudorapidity dependence of short-range correlations from a multi-phase transport model
Meijuan Wang🇨🇳 · Gang Chen🇨🇳 · Guoliang Ma🇨🇳 · Yuanfang Wu🇨🇳
Using a multi-phase transport model (AMPT) that includes both initial partonic and hadronic interactions, we study neighboring bin multiplicity correlations as a function of pseudorapidity in Au+Au collisions at $s_{N N} = 7.7 - 62.4$ GeV. It is observed that for $s_{N N} <$ 19.6GeV Au+Au collisions, the short-range correlations of final particles have a trough at central pseudorapidity, while for $s_{N N} >$ 19.6GeV AuAu collisions, the short-range correlations of final particles have a peak at central pseudorapidity. Our findings indicate that the pseudorapidity dependence of short-range correlations should contain some new physical information, and are not a simple result of the pseudorapidity distribution of final particles. The AMPT results with and without hadronic scattering are compared. It is found that hadron scattering can only increase the short-range correlations to some level, but is not responsible for the different correlation shapes for different energies. Further study shows that the different pseudorapidity dependence of short-range correlations are mainly due to partonic evolution and the following hadronization scheme.
nucl-thhep-phCPC(2016)·0 citations
06
FRIGA, A New Approach To Identify Isotopes and Hypernuclei In N-Body Transport Models
A. Le Fèvre🇩🇪 · Y. Leifels🇩🇪 · J. Aichelin🇫🇷 · Ch. Hartnack🇫🇷 · V. Kireyev🇷🇺 · E. Bratkovskaya🇩🇪
We present a new algorithm to identify fragments in computer simulations of relativistic heavy ion collisions. It is based on the simulated annealing technique and can be applied to n-body transport models like the Quantum Molecular Dynamics. This new approach is able to predict isotope yields as well as hyper-nucleus production. In order to illustrate its predicting power, we confront this new method to experimental data, and show the sensitivity on the parameters which govern the cluster formation.
nucl-thJ.Phys.Conf.Ser.(2016)·15 citations
07
Equation of state constraints for the cold dense matter inside neutron stars using the cooling tail method
J. Nättilä · A. W. Steiner · J. J. E. Kajava · V. F. Suleimanov · J. Poutanen
The cooling phase of thermonuclear (type-I) X-ray bursts can be used to constrain the neutron star (NS) compactness by comparing the observed cooling tracks of bursts to accurate theoretical atmosphere model calculations. By applying the so-called cooling tail method, where the information from the whole cooling track is used, we constrain the mass, radius, and distance for three different NSs in low-mass X-ray binaries 4U 1702-429, 4U 1724-307, and SAX J1810.8-260. Care is taken to only use the hard state bursts where it is thought that only the NS surface alone is emitting. We then utilize a Markov chain Monte Carlo algorithm within a Bayesian framework to obtain a parameterized equation of state (EoS) of cold dense matter from our initial mass and radius constraints. This allows us to set limits on various nuclear parameters and to constrain an empirical pressure-density relation for the dense matter. Our predicted EoS results in NS radius between 10.5-12.8 km (95% confidence limits) for a mass of 1.4 $M_{⊙}$ . Due to systematic errors and uncertainty in the composition these results should be interpreted as lower limits for the radius.
↳ astro-ph.HEnucl-thAstron.Astrophys.(2016)·144 citations
08
Fluctuations in the Statistical Model of the Early Stage of nucleus-nucleus collisions
R. V. Poberezhnyuk🇺🇦 · M. I. Gorenstein🇺🇦 · M. Gazdzicki🇩🇪
Predictions on fluctuations of hadron production properties in central heavy ion collisions are presented. They are based on the Statistical Model of the Early Stage and extend previously published results by considering the strongly intensive measures of fluctuations. In several of the considered cases a significant change in collision energy dependence of calculated quantities as a result of the phase transition is predicted. This provides an opportunity to observe new signals of the onset of deconfinement in heavy ion collisions experiments.
↳ hep-phnucl-thActa Phys.Polon.B(2016)·4 citations
09
Quantum Simulations of Nuclei and Nuclear Pasta with the Multi-resolution Adaptive Numerical Environment for Scientific Simulations
I. Sagert · G. I. Fann · F. J. Fattoyev · S. Postnikov · C. J. Horowitz
Neutron star and supernova matter at densities just below the nuclear matter saturation density is expected to form a lattice of exotic shapes. These so-called nuclear pasta phases are caused by Coulomb frustration. Their elastic and transport properties are believed to play an important role for thermal and magnetic field evolution, rotation and oscillation of neutron stars. Furthermore, they can impact neutrino opacities in core-collapse supernovae. In this work, we present proof-of-principle 3D Skyrme Hartree-Fock (SHF) simulations of nuclear pasta with the Multi-resolution ADaptive Numerical Environment for Scientific Simulations (MADNESS). We perform benchmark studies of $^{16} O$ , $^{208} Pb$ and $^{238} U$ nuclear ground states and calculate binding energies via 3D SHF simulations. Results are compared with experimentally measured binding energies as well as with theoretically predicted values from an established SHF code. The nuclear pasta simulation is initialized in the so-called waffle geometry as obtained by the Indiana University Molecular Dynamics (IUMD) code. The size of the unit cell is 24\:fm with an average density of about $ρ = 0.05 fm^{- 3}$ , proton fraction of $Y_{p} = 0.3$ and temperature of $T = 0$ MeV. Our calculations reproduce the binding energies and shapes of light and heavy nuclei with different geometries. For the pasta simulation, we find that the final geometry is very similar to the initial waffle state. In the present pasta calculations spin-orbit forces are not included but will be added in the future. Within the MADNESS framework, we can successfully perform calculations of inhomogeneous nuclear matter. By using pasta configurations from IUMD it is possible to explore different geometries and test the impact of self-consistent calculations on the latter.
↳ astro-ph.SRastro-ph.IMnucl-thPRC(2016)·26 citations
10
Strangeness production and long-range correlations in pp collisions in string fusion approach
Vladimir Kovalenko🇷🇺 · Vladimir Vechernin (Saint Petersburg State University, Russia)🇷🇺
The effects of string fusion on the correlations in strange particles production in proton-proton collisions at high energy are studied in the framework of a Monte Carlo string-parton model. The model is based on the strings formation in elementary dipole-dipole collisions. The hardness of the elementary interaction is defined by a transverse size of the colliding dipoles. The interaction between strings is realized in the accordance with the string fusion model prescriptions by the introduction of the lattice in the impact parameter plane and taking into account the finite rapidity length of strings. The particles species differentiation is implemented according to Schwinger mechanism. The parameters of the model are fixed with the experimental data on total inelastic cross section and charged multiplicity. In the framework of the model the long-range correlation functions with an accounting of strangeness have been studied. A new intensive event-by-event observable has been proposed, which characterizes the fraction of strange particles in the event. The predictions on the correlations between strangeness, multiplicity and mean transverse momentum are obtained for pp collisions at 7 TeV.
↳ hep-phnucl-thJ.Phys.Conf.Ser.(2016)·6 citations
11
The production of photons in relativistic heavy-ion collisions
Jean-François Paquet🇨🇦 · Chun Shen🇨🇦 · Gabriel S. Denicol🇺🇸 · Matthew Luzum🇪🇸 · Björn Schenke🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
In this work it is shown that the use of a hydrodynamical model of heavy ion collisions which incorporates recent developments, together with updated photon emission rates greatly improves agreement with both ALICE and PHENIX measurements of direct photons, supporting the idea that thermal photons are the dominant source of direct photon momentum anisotropy. The event-by-event hydrodynamical model uses IP-Glasma initial states and includes, for the first time, both shear and bulk viscosities, along with second order couplings between the two viscosities. The effect of both shear and bulk viscosities on the photon rates is studied, and those transport coefficients are shown to have measurable consequences on the photon momentum anisotropy.
↳ hep-phnucl-exnucl-thPRC(2016)·442 citations

Affiliations

first authorsco-authorsvia INSPIRE