Nuclear Theory·nucl-th

Tuesday·July 4, 2023

12 papers—6 primary·6 cross-listed

01
Source Function from Two-Particle Correlation Through Deblurring
Pierre Nzabahimana · Pawel Danielewicz
In heavy-ion collisions, low relative-velocity two-particle correlations have been a tool for assessing space-time characteristics of particle emission. Those characteristics may be cast in the form of a relative emission source related to the correlation function through the Koonin-Pratt (KP) convolution formula that involves the relative wave-function for the particles in its kernel. In the literature, the source has been most commonly sought by parametrizing it in a Gaussian form and fitting to the correlation function. At times the source was more broadly imaged from the function, still employing a fitting. Here, we propose the use of the Richardson-Lucy (RL) optical deblurring algorithm for deducing the source from a correlation function. The RL algorithm originally follows from probabilistic Bayesian considerations and relies on the intensity distributions for the optical object and its image, as well as the convolution kernel, being positive definite, which is the case for the corresponding quantities of interest within the KP formula.
nucl-thPLB(2023)·18 citations
02
Ab initio translationally invariant nucleon-nucleus optical potentials
M. Burrows · K. D. Launey · A. Mercenne · R. B. Baker · G. H. Sargsyan · T. Dytrych · D. Langr
We combine the \textit{ab initio} symmetry-adapted no-core shell model (SA-NCSM) with the single-particle Green's function approach to construct optical potentials rooted in first principles. Specifically, we show that total cross sections and phase shifts for neutron elastic scattering from a $^{4}$ He target with projectile energies between 0.5 and 10 MeV closely reproduce the experiment. In addition, we discuss an important new development that resolves a long-standing issue with spurious center-of-mass motion in the Green's function formalism for many-body approaches. The new development opens the path for first-principle predictions of cross sections for elastic scattering of single-nucleon projectiles, nucleon capture and deuteron breakup reactions, feasible for a broad range of open-shell spherical and deformed nuclei in the SA-NCSM approach.
nucl-thPRC(2024)·22 citations
03
Solving one-dimensional penetration problem for fission channel in the statistical Hauser-Feshbach theory
Toshihiko Kawano · Patrick Talou · Stephane Hilaire
We solve the Schrödinger equation for an arbitrary one-dimensional potential energy to calculate the transmission coefficient in the fission channel of compound nucleus reactions. We incorporate the calculated transmission coefficients into the statistical Hauser-Feshbach model calculation for neutron-induced reactions on $^{235, 238}$ U and $^{239}$ Pu. The one-dimensional model reproduces the evaluated fission cross section data reasonably well considering the limited number of model parameters involved. A resonance-like structure appears in the transmission coefficient for a double-humped fission barrier shape that includes an intermediate well, which is understood to be a quantum mechanical effect in the fission channel. The calculated fission cross sections for the neutron-induced reactions on $^{235, 238}$ U and $^{239}$ Pu all exhibit a similar structure.
nucl-thPRC(2024)·2 citations
04
Light projectile elastic scattering by nuclei described by the Gogny interaction
J. López Moraña · X. Viñas
In this work, we study the elastic scattering of some light particles, such as $^{2}$ H, $^{3}$ H, $^{3}$ He, and $^{4}$ He, by heavy target nuclei with an extended Watanabe model, which uses as input the neutron-nucleus and proton-nucleus optical potentials and the ground-state wave functions of the projectile. The nucleon-nucleus optical potential used in this work was obtained within a semi-microscopic nuclear matter approach, whose real and imaginary parts are provided by the first and second-order terms, respectively, of the Taylor expansion of the Brueckner-Hartree-Fock mass operator obtained with the reaction G-matrix built up with the Gogny force \cite{lopez21}. The angular distributions of the scattering of $^{2}$ H, $^{3}$ H, $^{3}$ He, and $^{4}$ He from different target nuclei and at a different incident energy of the projectile computed with this model are analyzed. The reaction cross-sections corresponding to some of these scattering processes are also calculated. Our results are compared with the experimental values as well as with another Watanabe calculation where the nucleon-nucleus the optical potential is provided by the phenomenological Köning-Delaroche model. The limitations of the extended Watanabe model used in this work are also discussed.
nucl-thPRC(2023)·2 citations
05
Hybrid Stars Built with Density Dependent Models
A. Issifu · F. M. da Silva · D.P. Menezes
Using a density dependent quark model and a relativistic model within the mean-field approximation for hadrons with density dependent meson-baryon couplings, we construct, for the first time, models that describe hybrid neutron stars consisting of nucleons and exotic baryons (hyperons and $Δ$ -resonances). We do the study using a Maxwell construction. The quark-hadron phase transition in the stellar matter is determined through; the structure, composition, and properties of the hybrid neutron star matter. The macroscopic properties of the star are determined, and the results for these particular models are found to be compatible with recent observational astrophysical data.
nucl-thMNRAS(2023)·14 citations
06
$β$ -decay half-lives as an indicator of shape-phase transition in neutron-rich Zr isotopes with particle-vibration coupling effect
Kenichi Yoshida · Yifei Niu · Futoshi Minato
[Background] $β$ -decay half-life is sensitive to the shell structure near the Fermi levels. Nuclear deformation thus impacts the $β$ -decay properties. [Purpose] A first-order shape-phase transition in neutron-rich Zr isotopes is predicted by some models. We investigate the $β$ -decay half-lives of neutron-rich nuclei around $^{110}$ Zr, where the shape-phase transition is predicted to occur, to see if the $β$ -decay half-life can be an indicator of the shape changes. [Method] The proton-neutron quasiparticle random-phase approximation (RPA) is adopted to calculate the Gamow-Teller transitions. In addition, we apply the quasiparticle phonon-vibrational coupling (PVC) to consider the phonon couplings. [Results] The spherical and oblate configurations give similar half-lives but shorter ones than the prolate configuration at the RPA level. The PVC effect further reduces the half-lives in general, but the effect is smaller for the deformed configuration than that for the spherical one. As a result, it makes the shape change from the oblate configuration to the spherical configuration visible. Therefore, a sudden shortening of $β$ -decay half-lives is always found at the nuclear shape changes. [Conclusions] $β$ -decay half-life is an indicator of the shape-phase transition. The shape mixing and the roles of the triaxial deformation are subject to study in the future.
nucl-thnucl-exPRC(2023)·11 citations
07
Properties of the $T_{cc} (3875)^{+}$ and $T_{c ˉ c ˉ} (3875)^{-}$ (and their heavy-quark spin partners) in nuclear matter
Victor Montesinos🇪🇸 · Miguel Albaladejo🇪🇸 · Juan Nieves🇪🇸 · Laura Tolos🇪🇸
We discuss the modification of the properties of the tetraquark-like $T_{cc} (3875)^{+}$ and $T_{c ˉ c ˉ} (3875)^{-}$ states in dense nuclear matter. We consider the $T_{cc}^{+}$ and $T_{c ˉ c ˉ}^{-}$ in vacuum as purely isoscalar $D^{*} D$ and $D^{*} D$ $S$ -wave bound states, respectively, dynamically generated from a heavy-quark effective interaction between the charmed mesons. We compute the $D$ , $D$ , $D^{*}$ , and $D^{*}$ spectral functions embedded in a nuclear medium and use them to determine the corresponding $T_{cc}^{+}$ and $T_{c ˉ c ˉ}^{-}$ self energies and spectral functions. We find important modifications of the $D^{*} D$ and $D^{*} D$ scattering amplitudes and of the pole position of these exotic states already for $ρ_{0} /2$ , with $ρ_{0}$ the normal nuclear density. We also discuss the dependence of these results on the $D^{*} D$ ( $D^{*} D$ ) molecular component in the $T_{cc}^{+}$ ( $T_{c ˉ c ˉ}^{-}$ ) wave-function. Owing to the different nature of the $D^{(*)} N$ and $D^{(*)} N$ interactions, we find characteristic changes of the in-medium properties of the $T_{cc} (3875)^{+}$ and $T_{c ˉ c ˉ} (3875)^{-}$ , which become increasingly visible as the density increases. The experimental confirmation of the found distinctive density-pattern will give support to the molecular picture of these tetraquark-like states, since in the case they were colourless compact quark structures the density behaviour of their respective nuclear medium spectral functions would likely be similar. Finally, we perform similar analyses for the isoscalar $J^{P} = 1^{+}$ heavy-quark spin symmetry partners of the $T_{cc}^{+}$ ( $T_{cc}^{*+}$ ) and the $T_{c ˉ c ˉ}^{-}$ ( $T_{c ˉ c ˉ}^{*-}$ ) by considering the $D^{* 0} D^{*+}$ and $D^{* 0} D^{*-}$ scattering $T -$ matrices.
↳ hep-phnucl-thPRC(2023)·25 citations
08
Simple Hamiltonian for Quantum Simulation of Strongly Coupled 2+1D SU(2) Lattice Gauge Theory on a Honeycomb Lattice
Berndt Müller🇺🇸 · Xiaojun Yao🇺🇸
We find a simple spin Hamiltonian to describe physical states of $2 + 1$ dimensional SU(2) lattice gauge theory on a honeycomb lattice with a truncation of the electric field representation at $j_{max} = \frac{1}{2}$ . The simple spin Hamiltonian only contains local products of Pauli matrices, even though Gauss's law has been completely integrated out.
↳ quant-phhep-lathep-phnucl-thPRD(2023)·42 citations
09
Dynamics of heavy flavour in a weakly magnetized hot QCD medium
Debarshi Dey🇮🇳 · Binoy krishna Patra🇮🇳
We obtain the spatial and momentum diffusion coefficients ( $D_{s}$ and $κ$ ), and the collisional energy loss ( $d E / d x$ ) of a heavy quark (HQ) traversing through a thermal medium of quarks and gluons in a weak magnetic field ( $B$ ), for the two cases of the HQ moving either parallel or perpendicular to $B$ . For that purpose, we consider Coulomb scatterings ( $t$ -channel) of the HQ with the light quarks, obtained from the imaginary part of the HQ self-energy via the cutting rules. Both the normalised (by $T^{3}$ ) %\textit{momentum} diffusion coefficients, $κ$ , as well as $d E / d x$ , for charm quarks are larger than that for bottom quarks due to the larger mass of the latter. Also, the effect of $B$ is more feeble on the bottom quark, compared to the charm quark. Comparatively, the magnitudes of both $κ$ and $d E / d x$ are significantly smaller for the case of $v ⊥ B$ . For both the cases, our results show that the momentum transfer between the HQ and the medium takes place preferentially along the direction of HQ velocity, thus leading to a significant increase in the momentum diffusion anisotropy, compared to $B = 0$ . We also calculate the (scaled) spatial diffusion coefficient, which we find to be independent of the heavy flavor mass and is almost unaffected by changes in $B$ .
↳ hep-phnucl-thPRD(2024)·9 citations
10
Neutral current neutrino and antineutrino scattering off the polarized nucleon
Krzysztof M. Graczyk🇵🇱 · Beata E. Kowal🇵🇱
The elastic and inelastic neutral current $ν$ ( $ν$ ) scattering off the polarized nucleon is discussed. The inelastic scattering concerns the single-pion production process. We show that the spin asymmetries' measurement can help to distinguish between neutrino and antineutrino neutral current scattering processes. The spin asymmetries also encode information about a type of target. Eventually, detailed studies of the inelastic spin asymmetries can improve understanding of the resonant-nonresonant pion production mechanism.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·4 citations
11
The Standard Model theory of neutron beta decay
Mikhail Gorchtein🇩🇪 · Chien-Yeah Seng🇺🇸
We review the status of the Standard Model theory of neutron beta decay. Particular emphasis is put on the recent developments in the electroweak radiative corrections. Given that some existing approaches give slightly different results, we thoroughly review the origin of discrepancies, and provide our recommended value for the radiative correction to the neutron and nuclear decay rates. The use of dispersion relation, lattice Quantum Chromodynamics and effective field theory framework allows for high-precision theory calculations at the level of $1 0^{- 4}$ , turning neutron beta decay into a powerful tool to search for new physics, complementary to high-energy collider experiments. We offer an outlook to the future improvements.
↳ hep-phnucl-exnucl-thUniverse(2023)·26 citations
12
Extraction of the strong coupling with HERA and EIC inclusive data
Salim Cerci🇹🇷 · Zuhal Seyma Demiroglu🇺🇸 · Abhay Deshpande🇺🇸 · Paul R. Newman🇬🇧 · Barak Schmookler🇺🇸 · Deniz Sunar Cerci🇹🇷 · Katarzyna Wichmann🇩🇪
Sensitivity to the strong coupling $α_{S} (M_{Z}^{2})$ is investigated using existing Deep Inelastic Scattering data from HERA in combination with projected future measurements from the Electron Ion Collider (EIC) in a next-to-next-to-leading order QCD analysis. A potentially world-leading level of precision is achievable when combining simulated inclusive neutral current EIC data with inclusive charged and neutral current measurements from HERA, with or without the addition of HERA inclusive jet and dijet data. The result can be obtained with substantially less than one year of projected EIC data at the lower end of the EIC centre-of-mass energy range. Some questions remain over the magnitude of uncertainties due to missing higher orders in the theoretical framework.
↳ hep-phhep-exhep-thnucl-ex+1EPJC(2023)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE