Nuclear Theory·nucl-th

Wednesday·June 22, 2022

24 papers—15 primary·9 cross-listed

16
Analytical calculations of the Quantum Tsallis thermodynamic variables
Ayman Hussein🇪🇬 · Trambak Bhattacharyya🇷🇺
In this article, we provide an account of analytical results related to the Tsallis thermodynamics that have been the subject matter of a lot of studies in the field of high-energy collisions. After reviewing the results for the classical case in the massless limit and for arbitrarily massive classical particles, we compute the quantum thermodynamic variables. For the first time, the analytical formula for the pressure of a Tsallis-like gas of massive bosons has been obtained. Hence, this article serves both as a brief review of the knowledge gathered in this area, and as an original research that forwards the existing scholarship. The results of the present paper will be important in a plethora of studies in the field of high-energy collisions including the propagation of non-linear waves generated by the traversal of high-energy particles inside the quark-gluon plasma medium showing the features of non-extensivity.
↳ cond-mat.stat-mechhep-phhep-thnucl-thMDPI Physics(2022)·1 citation
17
Non-radial oscillations and global stellar properties of anisotropic compact stars using realistic equations of state
Elvis J. Aquino Curi · Luis B. Castro · Cesar V. Flores · César H. Lenzi
In this work, we have made a systematic study of how the gravitational wave frequency of the fundamental mode from compact stars is affected by anisotropic effects using realistic equations of state. Our study is an extension of the seminal research performed by Doneva [Phys. Rev. D 85 (2012) 124023], where a polytropic equation of state was used. To achieve our objective, we considered compact stars which were built by using equations of state in the framework of a relativistic mean field theory for the case of hadronic stars and in the framework of the MIT model for the case of quark stars. In order to obtain some pertinent information that could give us the possibility to detect the anisotropy in compact stars, we also studied and analized the behaviour of various global stellar quantities, e.g., gravitational redshift, stellar mass, radius, among others. We concluded that the anisotropic effects can have important consequences, which are strongly related to the anisotropic parameter and the equation of state of high density matter. Additionally, a comparison with observational data has been made and we have shown that the anisotropic parameter $λ$ can be used as a tuning parameter to reproduce mass and radius observational data of neutron stars.
↳ gr-qcastro-ph.HEastro-ph.SRhep-ph+1EPJC(2022)·37 citations
18
Nuclei near and at the proton dripline
Marek Pfützner · Chiara Mazzocchi
Nuclei in the vicinity of the proton dripline and beyond it are a fascinating realm within the chart of nuclei. In this chapter the main phenomena that characterize this domain and are not to be found elsewhere are explored. While moving away from the $β$ -stability valley towards the proton dripline, phenomena like very exotic decay modes such as $β$ -delayed (multi-) particle emission, and proton-, or two-proton radioactivity are encountered. Landmark nuclei are here two isotopes with magic proton and neutron numbers, $^{48}$ Ni and $^{100}$ Sn. Moreover, proton-rich nuclei ( $N < Z$ ) display other interesting features, like breaking of isospin symmetry with consequent asymmetry in the energy spectra between mirror nuclei, the so-called Thomas-Ehrmann shift, or the phenomenon of proton-halo. Last but not least, nuclei close to the proton dripline play a very important role in nucleosynthesis, since they take part in the rapid-proton capture process and their properties are crucial in defining the flow followed and its termination close to $^{100}$ Sn.
↳ nucl-exnucl-th1 citation
19
Nucleon form factors and parton distributions in nonlocal chiral effective theory
P. Wang🇨🇳 · Fangcheng He🇨🇳 · Chueng-Ryong Ji🇺🇸 · W. Melnitchouk🇺🇸
We present a review of recent applications of nonlocal chiral effective theory to hadron structure studies. Starting from a nonlocal meson--baryon effective chiral Lagrangian, we show how the introduction of a correlation function representing the finite extent of hadrons regularizes the meson loop integrals and introduces momentum dependence in vertex form factors in a gauge invariant manner. We apply the framework to the calculation of nucleon electromagnetic form factors, unpolarized and polarized parton distributions, as well as transverse momentum dependent distributions and generalized parton distributions. Assuming that the nonlocal behavior is a general property of all interactions, we also discuss the application to the lepton anomalous magnetic moment in nonlocal QED.
↳ hep-phhep-exhep-latnucl-thPPNP(2023)·14 citations
20
Oscillation Modes and Gravitational Waves from Strangeon Stars
Hong-Bo Li🇨🇳 · Yong Gao🇨🇳 · Lijing Shao🇨🇳 · Ren-Xin Xu🇨🇳 · Rui Xu🇨🇳
The strong interaction at low energy scales determines the equation of state (EOS) of supranuclear matters in neutron stars (NSs). It is conjectured that the bulk dense matter may be composed of strangeons, which are quark clusters with nearly equal numbers of $u$ , $d$ , and $s$ quarks. To characterize the strong-repulsive interaction at short distance and the nonrelativistic nature of strangeons, a phenomenological Lennard-Jones model with two parameters is used to describe the EOS of strangeon stars (SSs). For the first time, we investigate the oscillation modes of non-rotating SSs and obtain their frequencies for various parameterizations of the EOS. We find that the properties of radial oscillations of SSs are different from those of NSs, especially for stars with relatively low central energy densities. Moreover, we calculate the $f$ -mode frequency of nonradial oscillations of SSs within the relativistic Cowling approximation. The frequencies of the $f$ -mode of SSs are found to be in the range from $6.7$ kHz to $8.7 kHz$ . Finally, we study the universal relations between the $f$ -mode frequency and global properties of SSs, such as the compactness and the tidal deformability. The results we obtained are relevant to pulsar timing and gravitational waves, and will help to probe NSs' EOSs and infer nonperturbative behaviours in quantum chromodynamics.
↳ gr-qcastro-ph.HEnucl-thMNRAS(2022)·28 citations
21
Search for possible alpha-condensate states in $^{20}$ Ne
A.S. Demyanova (1) · A.N. Danilov (1) · S.A. Goncharov (2) · V.I. Starastsin (1,3) · T.I Leonova (1,3) ((1) National Research Centre Kurchatov Institute, Moscow, Russia, (2) Lomonosov Moscow State University, Moscow, Russia, (3) National Research Nuclear University MEPhI, Moscow, Russia)
The root mean square radii of $^{20}$ Ne in the short-lived excited states were experimentally deduced for the first time from the analyses of $α$ + $^{20}$ Ne diffraction scattering. Differential cross sections of the elastic and inelastic $α$ + $^{20}$ Ne scattering in the incident energy range from a few MeV/nucleon up to 100 MeV/nucleon were analyzed by the modified diffraction model. No significant radius enhancement for the members of K $^{π}$ = 0 $_{1}^{+}$ and K $^{π}$ = 2 $^{-}$ bands in comparison with the ground state was observed. At the same time 20 % radius enhancement was obtained for the K $^{π}$ = 0 $_{1}^{-}$ band members. Moreover, for the 0 $_{2}^{+}$ state located above $α$ -emission threshold increased radius was observed. This result can speak in favor of possible $α$ -condensate structure of the 0 $_{2}^{+}$ state and can be considered as a possible analog of the famous 7.65-MeV 0 $_{2}^{+}$ Hoyle state of $^{12}$ C.
↳ nucl-exnucl-th0 citations
22
Near-BPS Skyrmions
Sven Bjarke Gudnason🇨🇳 · Marco Barsanti🇮🇹 · Stefano Bolognesi🇮🇹
We consider the Skyrme model in the near-BPS limit. The BPS part is made of the sextic term plus a potential and the deformation is made of the standard massive Skyrme model controlled by a small parameter $ϵ ≪ 1$ . In order to keep the perturbation under theoretical and computational control, we find a model for which BPS Skyrmions have compact support, henceforth denoted as compactons, and the spherically symmetric $B = 1$ Skyrmion represents the most stable solution. We use the $ϵ$ -expansion scheme to systematically calculate the corrections to the energy and compare with the exact numerical computations in the $B = 1$ sector. Finally, we use the $ϵ$ -expansion scheme to calculate the bound state of two $B = 1$ Skyrmions and its binding energy, which corresponds, prior to quantization, to the deuteron in our model.
↳ hep-thnucl-thJHEP(2022)·5 citations
23
Prospects of searching for unstable nucleus states in relativistic nuclear fragmentation
D.A. Aretemenkov · V. Bradnova · O.N Kashanskaya · N.V. Kondratieva · N.K. Kornegrutsa · E. Mitsova · N.G. Peresadko · V.V. Rusakova · R. Stanoeva · A.A. Zaitsev · P.I. Zarubin · I.G. Zarubina
The article is dedicated to the experimental study in the relativistic approach to the problems of nuclear cluster physics for the prospects of the \href{http://becquerel.jinr.ru/}{BECQUEREL} experiment. The nuclear emulsion method applied in this experiment makes it possible to study thoroughly the relativistic final states in the fragmentation of nuclei. The focus of the presented research is the dynamics of emergence of the $^{8}$ Be nucleus and the Hoyle state, as well as the search for the 4 $α$ -particle condensate decaying via the above nuclear states. In this context, the analysis of exposure to $^{84}$ Kr nuclei at 950 MeV/nucleon is shown. As a continuation of the study of light nuclei, we have demonstrated the search for the isobar-analogue state of the $^{13}$ N nucleus in the fragmentation of $^{14}$ N nuclei at 2 GeV/nucleon.
↳ nucl-exnucl-thPhys.Atom.Nucl.(2022)·4 citations
24
Renormalised spectral flows
Jens Braun🇩🇪 · Yong-rui Chen🇨🇳 · Wei-jie Fu🇨🇳 · Andreas Geißel🇩🇪 · Jan Horak🇩🇪 · Chuang Huang🇨🇳 · Friederike Ihssen🇩🇪 · Jan M. Pawlowski🇩🇪 · Manuel Reichert🇬🇧 · Fabian Rennecke🇩🇪 · Yang-yang Tan🇨🇳 · Sebastian Töpfel🇩🇪 · Jonas Wessely🇩🇪 · Nicolas Wink🇩🇪
We derive renormalised finite functional flow equations for quantum field theories in real and imaginary time that incorporate scale transformations of the renormalisation conditions, hence implementing a flowing renormalisation. The flows are manifestly finite in general non-perturbative truncation schemes also for regularisation schemes that do not implement an infrared suppression of the loops in the flow. Specifically, this formulation includes finite functional flows for the effective action with a spectral Callan-Symanzik cutoff, and therefore gives access to Lorentz invariant spectral flows. The functional setup is fully non-perturbative and allows for the spectral treatment of general theories. In particular, this includes theories that do not admit a perturbative renormalisation such as asymptotically safe theories. Finally, the application of the Lorentz invariant spectral functional renormalisation group is briefly discussed for theories ranging from real scalar and Yukawa theories to gauge theories and quantum gravity.
↳ hep-thhep-phnucl-thSciPost Phys.Core(2023)·65 citations

Affiliations

first authorsco-authorsvia INSPIRE