Nuclear Theory·nucl-th
11 papers—7 primary·4 cross-listed
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 production.
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.
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.
The hyperfine splitting of the ground and low-energy eV) levels in the Th nucleus in muonic atom (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 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 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.
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.
Blast-wave model is applied to describe the Hanbury-Brown--Twiss (HBT) radii of pionic systems produced in pp collisions at the LHC energies.
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.
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.
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.
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 tetraquark configuration are much higher than that of . This conclusion disfavors the possibility of 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.
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 , with denoting the collision energy, can be expressed as a universal function of the initial energy density , and the resulting pattern is in excellent agreement with data from and data over a wide range of energies and for different centralities.
first authorsco-authorsvia INSPIRE