Nuclear Theory·nucl-th

Thursday·September 7, 2023

9 papers—5 primary·4 cross-listed

01
[Submitted on 6 Sept 2023]
Nuclear Equation of State and many-body phase-space correlations in the Constrained Molecular Dynamics
Massimo Papa
Many-body correlations characterizing the Constrained Molecular Dynamics (CoMD)are analyzed in the case of finite and zero range effective microscopic interactions. The study begins by analyzing the case of infinite nuclear matter at zero temperature. A comparison with the predictions in the mean-field(MF) limit corresponding to different effective masses, highlights non-negligible differences regarding the produced Equation of State (EoS). A procedure is illustrated to determine the necessary corrections of the effective interaction parameters in the CoMD model so to reproduce the chosen EoS. The specific model calculations, the general feature of the discussed correlations gives a wider meaning to the resulting differences, which are in fact strongly related both to the Pauli principle constraint and to the localization effects related to wave-packets dynamics. Moving on to finite systems, preliminary results are shown in relation to the reaction mechanisms in the $^{64} N i +^{48} C a$ system described by the CoMD model. Therefore, the topic covered illustrates the effects produced by the correlations of the CoMD dynamics on the EoS and on some observables commonly studied in heavy ion collisions.
Comments:
v1 submitted to Nucl. Phys. A on 26/11/2022 v2 re-submitted on 27/07/2023 to be published on Nucl. Phys. A
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.02878 [pdf]
NPA(2024)·5 citations
02
[Submitted on 6 Sept 2023]
Effect of Backing on Neutron Spectra for Low Energy Quasi-Mono-energetic p+ $^{7}$ Li Reaction
H. Kumawat
$MO$ nte-carlo $N$ ucleon transport $C$ ode (MONC) for nucleon transport is extended for below 20MeV proton transport using ENDF and EXFOR data base. It is used to simulate p+ $^{7}$ Li reaction upto 20MeV proton energies and produced neutron spectra are reported here. The simulated results are compared with calculated values from other available codes like PINO, EPEN, SimLiT and experimental data. The spectra reported here can be used to get the neutron cross-section for the quasi-mono-energetic neutron reaction and will help to subtract the low energy contribution. The neutron spectra also useful as this reaction is used for accelerator based Boron Neutron Capture Therapy. The backing materials are used to fully stop the proton beam hence contribution from the neutrons from backing materials is estimated. It is found that Tantalum is good backing material below $\sim$ 8 MeV and Carbon is better at higher energies.
Comments:
arXiv admin note: text overlap with arXiv:2008.11502
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2309.02922 [pdf]
Nucl.Sci.Eng.(2025)·2 citations
03
[Submitted on 6 Sept 2023]
Production of doubly charmed hadron $Ξ_{cc}^{++}$ and $T_{cc}^{+}$ in relativistic heavy ion collisions
Baoyi Chen🇨🇳 · Meimei Yang🇨🇳 · Ge Chen🇬🇧 · Jiaxing Zhao🇫🇷 · Xiao-hai Liu🇨🇳
Heavy ion collisions provide a unique opportunity for studying the properties of exotic hadrons with two charm quarks. The production of $T_{cc}^{+}$ is significantly enhanced in nuclear collisions compared to proton-proton collisions due to the creation of multiple charm pairs. In this study, we employ the Langevin equation in combination with the Instantaneous Coalescence Model (LICM) to investigate the production of $T_{cc}^{+}$ and $Ξ_{cc}^{++}$ which consists of two charm quarks. We consider $T_{cc}^{+}$ as molecular states composed of $D$ and $D^{*}$ mesons. The Langevin equation is used to calculate the energy loss of charm quarks and $D$ mesons in the hot medium. The hadronization process, where charm quarks transform into each $D$ state as constituents of $T_{cc}^{+}$ production, is described using the coalescence model. The coalescence probability between $D$ and $D^{*}$ is determined by the Wigner function, which encodes the information of the $T_{cc}^{+}$ wave function. Our results show that the $T_{cc}^{+}$ production varies by approximately one order of magnitude when different widths in the Wigner function, representing distinct binding energies of $T_{cc}^{+}$ , are considered. This variation offers valuable insights into the nature of $T_{cc}^{+}$ through the analysis of its wave function. The $Ξ_{cc}^{++}$ is treated as a hadronic state produced at the hadronization of the deconfined matter. Its production is also calculated as a comparison with the molecular state $T_{cc}^{+}$ .
Comments:
8 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2309.02987 [pdf]
PRC(2024)·6 citations
04
[Submitted on 6 Sept 2023]
Polarization of Thermal Dilepton Radiation
Florian Seck🇩🇪 · Bengt Friman🇩🇪 · Tetyana Galatyuk🇩🇪 · Hendrik van Hees🇩🇪 · Ralf Rapp🇺🇸 · Enrico Speranza🇺🇸 · Jochen Wambach🇩🇪
The invariant mass spectra of dileptons radiated from the fireballs formed in high-energy heavy-ion collisions have been successfully used to investigate the properties of hot and dense QCD matter. Using a realistic model for the in-medium electromagnetic spectral function, we predict polarization observables and compare them to experiment. This allows, for the first time, independent tests of the longitudinal and transverse components of the virtual photon's selfenergy. While the low- and high-mass regions exhibit the expected limits of transverse and unpolarized photons, respectively, baryon-driven medium effects in the $ρ$ -meson mass region create a marked longitudinal polarization that transits into a largely unpolarized emission from the quark-gluon plasma, thus providing a sensitive test of microscopic emission processes in QCD matter. Applications to available data from the HADES and NA60 experiments at SIS and SPS energies, respectively, are consistent with our predictions and set the stage for quantitative polarization studies at FAIR and collider energies.
Comments:
7 pages, 3 figures, minor changes to the text, results unchanged, matches published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.03189 [pdf]
PLB(2025)·15 citations
05
[Submitted on 6 Sept 2023]
Complex scaling in finite volume
Hang Yu · Nuwan Yapa · Sebastian König
Quantum resonances, i.e., metastable states with a finite lifetime, play an important role in nuclear physics and other domains. Describing this phenomenon theoretically is generally a challenging task. In this work, we combine two established techniques to address this challenge. Complex scaling makes it possible to calculate resonances with bound-state-like methods. Finite-volume simulations exploit the fact that the infinite-volume properties of quantum systems are encoded in how discrete energy levels change as one varies the size of the volume. We apply complex scaling to systems in finite periodic boxes and derive the volume dependence of states in this scenario, demonstrating with explicit examples how one can use these relations to infer infinite-volume resonance energies and lifetimes.
Comments:
13 pages, 7 figures, matched published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2309.03196 [pdf]
PRC(2024)·9 citations
06
[Submitted on 5 Sept 2023] (cross-list from hep-ph)
Nucleon axial-vector form factor and radius from future neutrino experiments
Roberto Petti🇺🇸 · Richard J. Hill🇺🇸 · Oleksandr Tomalak🇺🇸
Precision measurements of antineutrino elastic scattering on hydrogen from future neutrino experiments offer a unique opportunity to access the low-energy structure of protons and neutrons. We discuss the determination of the nucleon axial-vector form factor and radius from antineutrino interactions on hydrogen that can be collected at the future Long-Baseline Neutrino Facility, and study the sources of theoretical and experimental uncertainties. The projected accuracy would improve existing measurements by $1$ order of magnitude and be competitive with contemporary lattice-QCD determinations, potentially helping to resolve the corresponding tension with measurements from (anti)neutrino elastic scattering on deuterium. We find that the current knowledge of the nucleon vector form factors could be one of the dominant sources of uncertainty. We also evaluate the constraints that can be simultaneously obtained on the absolute $ν ˉ_{μ}$ flux normalization.
Comments:
14 pages, 5 figures, v2: version published in Physical Review D, Equation 9, and Table 1 updated, minor text updates
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2309.02509 [pdf]
PRD(2024)·18 citations
07
[Submitted on 6 Sept 2023] (cross-list from nucl-ex)
Surprising charge-radius kink in the Sc isotopes at N=20
Kristian König · Stephan Fritzsche · Gaute Hagen · Jason D. Holt · Andrew Klose · Jeremy Lantis · Yuan Liu · Kei Minamisono · Takayuki Miyagi · Witold Nazarewicz · Thomas Papenbrock · Skyy V. Pineda · Robert Powel · Paul-Gerhard Reinhard
Charge radii of neutron deficient 40Sc and 41Sc nuclei were determined using collinear laser spectroscopy. With the new data, the chain of Sc charge radii extends below the neutron magic number N=20 and shows a pronounced kink, generally taken as a signature of a shell closure, but one notably absent in the neighboring Ca, K and Ar isotopic chains. Theoretical models that explain the trend at N=20 for the Ca isotopes cannot reproduce this puzzling behavior.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2309.02839 [pdf]
PRL(2023)·32 citations
08
[Submitted on 6 Sept 2023] (cross-list from hep-ph)
Influence of dynamical screening of four-quarks interaction on the chiral phase diagram
Michał Szymański🇵🇱 · Pok Man Lo🇵🇱 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱
We investigate the effect of screening of the four-quarks contact interactions by the ring diagram at finite temperature and density in an effective chiral model inspired by QCD in the Coulomb gauge. As a consequence, a medium-dependent coupling naturally emerges which, in a class of chiral models, brings the chiral crossover temperature down to the value calculated in LQCD at low net-baryon density. Furthermore, it implies a stronger divergence of the chiral susceptibility at the critical point compared to the mean-field dynamics. At vanishing temperature, however, the transition sets in at unphysically small chemical potential, indicating a need for additional effects to compensate for the screening strength. We discuss the properties of an effective potential for a class of models described by momentum-independent gap equations. In particular, we introduce the method to construct an approximate effective potential from the gap equations to determine the location of the first-order phase transition.
Comments:
12 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.03124 [pdf]
PRD(2024)·3 citations
09
[Submitted on 6 Sept 2023] (cross-list from hep-th)
Magnetized Baryonic layer and a novel BPS bound in the gauged-Non-Linear-Sigma-Model-Maxwell theory in (3+1)-dimensions through Hamilton-Jacobi equation
Fabrizio Canfora🇨🇱
It is show that one can derive a novel BPS bound for the gauged Non-Linear-Sigma-Model (NLSM) Maxwell theory in (3+1) dimensions which can actually be saturated. Such novel bound is constructed using Hamilton-Jacobi equation from classical mechanics. The configurations saturating the bound represent Hadronic layers possessing both Baryonic charge and magnetic flux. However, unlike what happens in the more common situations, the topological charge which appears naturally in the BPS bound is a non-linear function of the Baryonic charge. This BPS bound can be saturated when the surface area of the layer is quantized. The far-reaching implications of these results are discussed. In particular, we determine the exact relation between the magnetic flux and the Baryonic charge as well as the critical value of the Baryonic chemical potential beyond which these configurations become thermodynamically unstable.
Comments:
14 pages, No figure, typos corrected. Discussion on charge condensation included. Notation improved. Version accepted for publication on Journal of High Energy Physics (JHEP)
Subjects:
High Energy Physics — Theory (hep-th); High Energy Astrophysical Phenomena (astro-ph.HE); Superconductivity (cond-mat.supr-con); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2309.03153 [pdf]
JHEP(2023)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE