Nuclear Theory·nucl-th

Friday·January 31, 2020

8 papers—3 primary·5 cross-listed

01
The QCD phase diagram and statistics friendly distributions
Volker Koch🇺🇸 · Adam Bzdak🇵🇱 · Dmytro Oliinychenko🇺🇸 · Jan Steinheimer🇩🇪
The preliminary STAR data for proton cumulants for central collisions at \sqrt{s}=7.7 GeV are consistent with a two-component proton multiplicity distribution. We show that this two-component distribution is statistics friendly in that factorial cumulants of surprisingly high orders may be extracted with a relatively small number of events. As a consequence the two-component model can be tested and verified right now with the presently available STAR data from the first phase of the RHIC beam energy scan.
nucl-thNPA(2021)·5 citations
02
Production of $^{4} Li$ and $p -^{3} He$ correlation function in relativistic heavy-ion collisions
Sylwia Bazak🇵🇱 · Stanislaw Mrowczynski🇵🇱
The thermal and coalescence models both describe well yields of light nuclei produced in relativistic heavy-ion collisions at LHC. We propose to measure the yield of $^{4} Li$ and compare it to that of $^{4} He$ to falsify one of the models. Since the masses of $^{4} He$ and $^{4} Li$ are almost equal, the yield of $^{4} Li$ is about 5 times bigger than that of $^{4} He$ in the thermal model because of different numbers of spin states of the two nuclides. Their internal structures are, however, very different: the alpha particle is well bound and compact while $^{4} Li$ is weakly bound and loose. Consequently, the ratio of yields of $^{4} Li$ to $^{4} He$ is significantly smaller in the coalescence model and it strongly depends on the collision centrality. Since the nuclide $^{4} Li$ is unstable and it decays into $^{3} He$ and $p$ , the yield of $^{4} Li$ can be experimentally obtained through a measurement of the $p -^{3} He$ correlation function. The function carries information not only about the yield of $^{4} Li$ but also about the source of $^{3} He$ and allows one to determine through a source-size measurement whether of $^{3} He$ is directly emitted from the fireball or it is formed afterwards. We compute the correlation function taking into account the $s -$ wave scattering and Coulomb repulsion together with the resonance interaction responsible for the $^{4} Li$ nuclide. We discuss how to infer information about an origin of $^{3} He$ from the correlation function, and finally a method to obtain the yield of $^{4} Li$ is proposed.
nucl-thhep-phnucl-exEPJA(2020)·27 citations
03
Angular distribution of fragments in neutron-induced nuclear fission at energies 1-200 MeV: data, theoretical models and relevant problems
A. L. Barabanov · A. S. Vorobyev · A. M. Gagarski · O. A. Shcherbakov · L. A. Vaishnene
In recent years, investigations of angular distributions of fragments in neutron-induced nuclear fission have been extended to intermediate energies, up to 200 MeV, as well as to a wide range of target isotopes. Using as an example the latest data obtained by our group for the reaction 237-Np(n,f), we discuss the specific features of fission fragment angular distribution and present a method for their simulation based on the code TALYS. It is shown that a simplified model reasonably describes energy dependence of the angular distribution in the whole range 1-200 MeV. The ways to improve the model are discussed along with the possibilities to use it for obtaining new information on fission and pre-equilibrium processes in neutron-nucleus interaction. We consider also the relevant problems of describing fission fragment angular distributions.
nucl-thnucl-exEPJ Web Conf.(2021)·3 citations
04
Role of the crust on the tidal deformability of a neutron star within a unified treatment of dense matter
Loïc Perot🇧🇪 · Nicolas Chamel🇧🇪 · Aurélien Sourie🇧🇪
The role of the crust on the tidal deformability of a cold nonaccreted neutron star is studied using the recent unified equation of state BSk24. This equation of state, which is based on the nuclear-energy density functional theory, provides a thermodynamically consistent description of all stellar regions. Results obtained with this equation of state are compared to those calculated for a putative neutron star made entirely of homogeneous matter. The presence of the crustal layers is thus found to significantly reduce the Love number $k_{2}$ , especially for low-mass stars. However, this reduction mainly arises from the increase in the stellar radius almost independently of the equation of state. This allows for a simple analytic estimate of $k_{2}$ for realistic neutron stars using the equation of state of homogeneous matter only.
↳ astro-ph.HEgr-qcnucl-thPRC(2020)·31 citations
05
Electromagnetic radiation from the pre-equilibrium/pre-hydro stage of the quark-gluon plasma
Jessica Churchill🇨🇦 · Li Yan🇨🇳 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
Photons produced in the pre-equilibrium/pre-hydro stage of the quark-gluon plasma produced in relativistic heavy-ion collisions were computed using parton distribution functions obtained from solutions of the Boltzmann equation. The effect of the initial gluon momentum anisotropy $ξ$ and the dependence on the saturation momentum $Q_{s}$ was investigated. We see that small $Q_{s}$ results in a photon yield enhancement, whereas a larger $Q_{s}$ results in a pre-equilibrium photon suppression, owing to the strict constraint of matching to experimental energy density.
↳ hep-phnucl-exnucl-thNPA(2021)·8 citations
06
Computing real time correlation functions on a hybrid classical/quantum computer
Niklas Mueller🇺🇸 · Andrey Tarasov🇺🇸 · Raju Venugopalan🇺🇸
Quantum devices may overcome limitations of classical computers in studies of nuclear structure functions and parton Wigner distributions of protons and nuclei. In this talk, we discuss a worldline approach to compute nuclear structure functions in the high energy Regge limit of QCD using a hybrid quantum computer, by expressing the fermion determinant in the QCD path integral as a quantum mechanical path integral over $0 + 1$ -dimensional fermionic and bosonic world-lines in background gauge fields. Our simplest example of computing the well-known dipole model result for the structure function $F_{2}$ in the high energy Regge limit is feasible with NISQ era technology using few qubits and shallow circuits. This example can be scaled up in complexity and extended in scope to compute structure functions, scattering amplitudes and other real-time correlation functions in QCD, relevant for example to describe non-equilibrium transport of quarks and gluons in a Quark-Gluon-Plasma.
↳ hep-thhep-phnucl-thquant-phNPA(2021)·10 citations
07
Astronuclear Physics: a Tale of the Atomic Nuclei in the Skies
M. Arnould · S. Goriely
A century ago, nuclear physics entered astrophysics, giving birth to a new field of science referred to as "Nuclear Astrophysics". With time, it developed at an impressive pace into a vastly inter- and multidisciplinary discipline bringing into its wake not only astronomy and cosmology, but also many other sub-fields of physics, especially particle, solid-state and computational physics, as well as chemistry, geology and even biology. The present Astronuclear Physics review focusses primarily on the facets of nuclear physics that are of relevance to astronomy and astrophysics, the theoretical aspects being of special concern here.
↳ astro-ph.SRnucl-thPPNP(2020)·115 citations
08
Electromagnetic and weak probes: theory
Ralf-Arno Tripolt🇩🇪
An overview of the latest theoretical developments and results on electromagnetic and weak probes in relativistic heavy-ion collisions is presented. The possibilities to use electromagnetic probes, i.e., photons and dileptons, as a spectrometer, thermometer, chronometer, polarimeter, barometer, and multimeter of the collision system, as well as to explore the QCD phase diagram and to locate phase transitions such as the critical endpoint, are discussed.
↳ hep-phnucl-thNPA(2021)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE