Nuclear Theory·nucl-th

Tuesday·January 9, 2024

10 papers—3 primary·7 cross-listed

01
Systematic shell-model study of $^{99 - 129}$ Cd isotopes and isomers in neutron-rich $^{127 - 131}$ In isotopes
Deepak Patel · Praveen C. Srivastava · Noritaka Shimizu · Yutaka Utsuno
Systematic shell-model calculations are presented for odd-mass Cd isotopes with $N = 51 - 81$ utilizing a combination of a $G$ -matrix interaction and a semiempirical one. The excited energy spectra and electromagnetic transition probabilities are compared with the recently available experimental data. We have found that the observed quadrupole moments in the $11/ 2_{1}^{-}$ states that linearly change with the neutron number are well accounted for by the dominance of prolate shapes throughout the Cd isotope chain. We have also described the properties of several isomeric states in neutron-rich $^{127 - 131}$ In isotopes that were recently observed in Jyväskylä.
nucl-thnucl-exPRC(2024)·5 citations
02
High-order Shakhov-like extension of the relaxation time approximation in relativistic kinetic theory
Victor E. Ambruş · David Wagner
In this paper we present a relativistic Shakhov-type generalization of the Anderson-Witting relaxation time model for the Boltzmann collision integral. The extension is performed by modifying the path on which the distribution function $f_{k}$ is taken towards local equilibrium $f_{0 k}$ , by replacing $f_{k} - f_{0 k}$ via $f_{k} - f_{S k}$ . The Shakhov-like distribution $f_{S k}$ is constructed using $f_{0 k}$ and the irreducible moments $ρ_{r}^{μ_{1} \dots μ_{ℓ}}$ of $f_{k}$ and reduces to $f_{0 k}$ in local equilibrium. Employing the method of moments, we derive systematic high-order Shakhov extensions that allow both the first- and the second-order transport coefficients to be controlled independently of each other. We illustrate the capabilities of the formalism by tweaking the shear-bulk coupling coefficient $λ_{Π π}$ in the frame of the Bjorken flow of massive particles, as well as the diffusion-shear transport coefficients $ℓ_{V π}$ , $ℓ_{π V}$ in the frame of sound wave propagation in an ultrarelativistic gas. Finally, we illustrate the importance of second-order transport coefficients by comparison with the results of the stochastic BAMPS method in the context of the one-dimensional Riemann problem.
nucl-thphysics.flu-dynPRD(2024)·6 citations
03
Characterizing the initial and final state effects in isobaric collisions at energies available at the BNL Relativistic Heavy Ion Collider
Niseem Magdy🇺🇸
The Multi-Phase Transport model (AMPT) is employed to predict Symmetric Correlations (SC), Asymmetric Correlations (ASC), Normalized Symmetric Correlations (NSC), and Normalized Asymmetric Correlations (NASC) in $^{96} R u +^{96} R u$ and $^{96} Z r +^{96} Z r$ collisions at 200~GeV. Our study offers insights into the behavior of SC, ASC, NSC, and NASC, considering various nuclear structure scenarios to account for differences between the two isobars. Additionally, we emphasize the importance of detailed experimental measurements as they will serve as a critical constraint for refining the predictions of theoretical models.
nucl-thnucl-exPRC(2024)·6 citations
04
N $^{3}$ LO Power Corrections for $0$ -jettiness Subtractions With Fiducial Cuts
Gherardo Vita🇨🇭
We compute the leading logarithmic power corrections at next-to-next-to-next-to-leading order for $0$ -jettiness subtractions for color singlet production. We discuss how to disentangle these power corrections from those arising from the presence of fiducial and isolation cuts by using Projection-to-Born improved slicing. We present the results for Drell-Yan and Higgs production in gluon fusion differential in both the invariant mass and rapidity of the color singlet. Our results include all the channels contributing at leading logarithmic order for these processes, including the off-diagonal channels that receive contributions from soft quark emission. We study the numerical impact of the power corrections for Drell-Yan and Higgs production and find it to become negligible compared to the size of the N $^{3}$ LO corrections only below $τ_{cut} \sim 1 0^{- 5}$ . We estimate that in a fully differential calculation at N $^{3}$ LO combining the Projection-to-Born improved slicing method and our results for the leading logarithmic power corrections may allow for keeping the slicing uncertainties under control already with $τ_{cut} ≲ 1 0^{- 3}$ , marking a significant improvement in efficiency for these methods. These results constitute a crucial ingredient for fully differential N $^{3}$ LO calculations based on the $N$ -jettiness subtraction scheme.
↳ hep-phnucl-thJHEP(2024)·12 citations
05
Neutron beta decay and exact conservation of charged weak hadronic vector current in the Standard Model
Derar Altarawneh🇯🇴 · Roman Höllwieser🇩🇪 · Markus Wellenzohn🇦🇹
We investigate a reliability of the hypothesis of exact conservation of the charged weak hadronic vector current in the neutron $β^{-}$ -decay with polarized neutron and unpolarized proton and electron. We calculate the contributions of the phenomenological term, responsible for Exact Conservation of the charged weak hadronic Vector Current (or the ECVC effect) in the neutron $β^{-}$ -decay even for different masses of the neutron and proton (see Leitner et al. Phys. Rev. C73, 065502 (2006)), to the correlation coefficients together with a complete set of contributions of scalar and tensor interactions beyond the Standard Model (SM). We argue if total contributions of scalar and tensor interactions beyond the SM (Phys. Rev. D88, 073002 (2013); arXiv: 1212.0332v4 [hep-ph]) will not be able to reconcile the experimental data on the correlation coefficients with the contributions of the ECVC effect, one may conclude that the charged weak hadronic vector current is not conserved in the hadronic transitions of weak processes with different masses of incoming and outgoing hadrons.
↳ hep-phnucl-thUniverse(2024)·4 citations
06
Can $G W$ Handle Multireference Systems?
Abdallah Ammar🇫🇷 · Antoine Marie🇫🇷 · Mauricio Rodríguez-Mayorga🇫🇷 · Hugh G. A. Burton🇬🇧 · Pierre-François Loos🇫🇷
Due to the infinite summation of bubble diagrams, the $G W$ approximation of Green's function perturbation theory has proven particularly effective in the weak correlation regime, where this family of Feynman diagrams is important. However, the performance of $G W$ in multireference molecular systems, characterized by strong electron correlation, remains relatively unexplored. In the present study, we investigate the ability of $G W$ to handle closed-shell multireference systems in their singlet ground state by examining four paradigmatic scenarios. Firstly, we analyze a prototypical example of a chemical reaction involving strong correlation: the potential energy curve of \ce{BeH2} during the insertion of a beryllium atom into a hydrogen molecule. Secondly, we compute the electron detachment and attachment energies of a set of molecules that exhibit a variable degree of multireference character at their respective equilibrium geometries: \ce{LiF}, \ce{BeO}, \ce{BN}, \ce{C2}, \ce{B2}, and \ce{O3}. Thirdly, we consider a \ce{H6} cluster with a triangular arrangement, which features a notable degree of spin frustration. Finally, the dissociation curve of the \ce{HF} molecule is studied as an example of single bond breaking. These investigations highlight a nuanced perspective on the performance of $G W$ for strong correlation, depending on the level of self-consistency, the choice of initial guess, and the presence of spin-symmetry breaking at the Hartree-Fock level.
↳ physics.chem-phcond-mat.mtrl-scicond-mat.str-elnucl-thJ.Chem.Phys.(2024)·5 citations
07
Bayesian inference of multimessenger astrophysical data: Joint and coherent inference of gravitational waves and kilonovae
Matteo Breschi🇩🇪 · Rossella Gamba🇩🇪 · Gregorio Carullo🇩🇪 · Daniel Godzieba🇺🇸 · Sebastiano Bernuzzi🇩🇪 · Albino Perego🇮🇹 · David Radice🇺🇸
We present a Bayesian framework for joint and coherent analyses of multimessenger binary neutron star signals. The method, implemented in our bajes infrastructure, incorporates a joint likelihood for multiple datasets, support for various semi-analytical kilonova models and numerical-relativity (NR) informed relations for the mass ejecta, as well as a technique to include and marginalize over modeling uncertainties. As a first application, we analyze the gravitational-wave GW170817 and the kilonova AT2017gfo data. These results are then combined with the most recent X-ray pulsars analyses of PSR J0030+0451 and PSR J0740+6620 to obtain EOS constraints.Various constraints on the mass-radius diagram and neutron star properties are then obtained by resampling over a set of ten million parametrized EOS built under minimal assumptions. We find that a joint and coherent approach improves the inference of the extrinsic parameters (distance) and, among the instrinc parameters, the mass ratio. The inclusion of NR informed relations strongly improves over the case of using an agnostic prior on the intrinsic parameters. Comparing Bayes factors, we find that the two observations are better explained by the common source hypothesis only by assuming NR-informed relations. These relations break some of the degeneracies in the employed kN models. The EOS inference folding-in PSR J0952-0607 minimum-maximum mass, PSR J0030+0451 and PSR J0740+6620 data constrains, among other quantities, the neutron star radius to $R_{1.4} = 12.30_{- 0.56}^{+ 0.81}$ km ( $R_{1.4} = 13.20_{- 0.90}^{+ 0.91}$ km) and the maximum mass to $M_{ma x} = 2.28_{- 0.17}^{+ 0.25} M_{⊙}$ ( $M_{ma x} = 2.32_{- 0.19}^{+ 0.30} M_{⊙}$ ) where the ST+PDT (PDT-U) analysis of Vinciguerra et a (2023) for PSR J0030+0451 is employed. Hence, the systematics on PSR J0030+0451 data reduction currently dominate the mass-radius diagram constraints.
↳ astro-ph.HEastro-ph.IMnucl-thAstron.Astrophys.(2024)·36 citations
08
Anomalous diffusion of the heavy quarks through the fractional Langevin equation
Jai Prakash🇮🇳
The dynamics of heavy quarks within the hot QCD medium have been revisited, considering the influence of anomalous diffusion. This study has been conducted using the framework of the fractional Langevin equation involving the Caputo fractional derivative. We introduce a numerical scheme for the fractional Langevin equation and demonstrate that the mean square displacement of the particle exhibits anomalous diffusion, deviating from a linear relationship with time. Our analysis calculates various entities, such as mean squared momentum, momentum spread, and the nuclear suppression factor, $R_{AA}$ . Notably, our findings indicate that superdiffusion strongly suppresses the $R_{AA}$ compared to normal diffusion in the hot QCD medium. The possible impacts on other parameters are also discussed.
↳ hep-phnucl-thPRD(2024)·6 citations
09
Split of the pseudo-critical temperatures of chiral and confine/deconfine transitions by temperature gradient
Ji-Chong Yang🇨🇳 · Wen-Wen Li🇨🇳 · Chong-Xing Yue🇨🇳
Searching of the critical endpoint of the phase transition of Quantum Chromodynamics~(QCD) matter in experiments is of great interest. The temperature in the fireball of a collider is location dependent, however, most theoretical studies address the scenario of uniform temperature. In this work, the effect of temperature gradients is investigated using lattice QCD approach. We find that the temperature gradient catalyzes chiral symmetry breaking, meanwhile the temperature gradient increases the Polyakov loop in the confined phase but suppresses the Polyakov loop in the deconfined phase. Furthermore, the temperature gradient decreases the pseudo-critical temperature of chiral transition but increases the pseudo-critical temperature of the confine/deconfine transition.
↳ hep-lathep-phnucl-thPRD(2024)·2 citations
10
New theoretical developments on the early-time dynamics and approach to equilibrium in Heavy-Ion collisions
Soeren Schlichting🇩🇪
We discuss recent theoretical developments in understanding the early pre-equilibrium dynamics and onset of hydrodynamic behavior in high-energy heavy-ion collisions. We highlight possible experimental signatures of the pre-equilibrium phase, and present recent progress in developing a consistent theoretical description of collective flow in small systems.
↳ hep-phnucl-thEPJ Web Conf.(2024)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE