Nuclear Theory·nucl-th

Tuesday·December 19, 2023

25 papers—12 primary·13 cross-listed

01
[Submitted on 15 Dec 2023]
Studying short-range nuclear correlations using relativistic heavy-ion collisions
Matthew Luzum🇧🇷 · João Paulo Picchetti🇧🇷 · Mauricio Hippert🇺🇸 · Jean-Yves Ollitrault🇫🇷
Recently, a method was developed for implementing arbitrary short-range nucleon-nucleon correlations in Monte Carlo sampled nuclei (as well as deformations of the 1-body nuclear density). We use this method to implement realistic 2-body correlations in a sample of nuclei for use in simulations of relativistic heavy-ion collisions and we quantify the statistical benefits. These results demonstrate that the method can be used to easily implement an arbitrary correlation function, and systematically study the effects of correlations using significantly less resources than is necessary with traditional methods.
Comments:
4 pages, 3 figures. Proceedings for Quark Matter 2023
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.10129 [pdf]
EPJ Web Conf.(2024)·1 citation
02
[Submitted on 15 Dec 2023]
Which first order phase transitions to quark matter are possible in neutron stars?
Jan-Erik Christian🇩🇪 · Jürgen Schaffner-Bielich🇩🇪 · Stephan Rosswog🇩🇪
We examine which first order phase transitions are consistent with today's astrophysical constraints. In particular, we explore how a well-constrained mass-radius data point would restrict the admissible parameter space and to this end, we employ the most likely candidates of the recent NICER limits of PSR J0030+0451. To systematically vary the stiffness of the equation of state, we employ a parameterizable relativistic mean field equation of state, which is in compliance with results from chiral effective field theory. We model phase transitions via Maxwell constructions and parameterize them by means of the transitional pressure $p_{trans}$ and the jump in energy density $Δ ϵ$ . This provides us with a generic setup that allows for rather general conclusions to be drawn. We outline some regions in the $p_{trans}$ - $Δ ϵ$ parameter space that may allow for a phase transition identification in the near future. We also find that a strongly constrained data point, at either exceptionally large or small radii, would reduce the parameter space to such an extent that mass and radius become insufficient indicators of a phase transition.
Comments:
14 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2312.10148 [pdf]
PRD(2024)·40 citations
03
[Submitted on 15 Dec 2023]
Transverse momentum fluctuation in ultra-central Pb+Pb collision at the LHC
Rupam Samanta🇵🇱 · Somadutta Bhatta🇺🇸 · Jiangyon Jia🇺🇸 · Matthew Luzum🇧🇷 · Jean-Yves Ollitrault🇫🇷
The ATLAS collaboration has recently observed that the variance of the transverse momentum per particle ( $[p_{t}]$ ), when measured as a function of the collision multiplicity ( $N_{c h}$ ) in Pb+Pb collisions, decreases by a factor $2$ for the largest values of $N_{c h}$ , corresponding to ultra-central collisions. We show that this phenomenon is naturally explained by invoking impact parameter ( $b$ ) fluctuations, which contribute to the variance, and gradually disappear in ultra-central collisions. It implies that $N_{c h}$ and $[p_{t}]$ are strongly correlated at fixed $b$ , which is explained by the local thermalization of the QGP medium.
Comments:
4 pages, 2 figures, contribution to the proceedings of Quark Matter 2023, Houston
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.10161 [pdf]
EPJ Web Conf.(2024)·0 citations
04
[Submitted on 15 Dec 2023]
Thermal dilepton production in heavy-ion collisions at beam-energy-scan (BES) energies
Jessica Churchill🇨🇦 · Lipei Du🇨🇦 · Bailey Forster🇨🇦 · Han Gao🇨🇦 · Greg Jackson🇫🇷 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦
The lepton pair production rate at finite temperature and at next-to-leading-order (NLO) is calculated for quark-gluon plasma at non-zero baryon density. Yields are obtained using a (3+1)D multicomponent simulation capable of reproducing hadronic observables measured in the RHIC Beam Energy Scan. Spectra of intermediate invariant mass dileptons are compared with measurements from the STAR collaboration. The result of a study where the temperature information obtained from the dilepton spectrum from heavy-ion collisions performed at different energies and centralities is presented.
Comments:
4 pages, 3 figures. Contribution to the proceedings of Quark Matter 2023 (Houston, TX, 3-9 Sep. 2023)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.10166 [pdf]
EPJ Web Conf.(2024)·4 citations
05
[Submitted on 15 Dec 2023]
Why are hydrodynamic theories applicable beyond the hydrodynamic regime?
Sunil Jaiswal🇺🇸 · Jean-Paul Blaizot🇫🇷 · Rajeev S. Bhalerao🇮🇳 · Zenan Chen🇨🇳 · Amaresh Jaiswal🇮🇳 · Li Yan🇨🇳
We present an alternative approach to deriving second-order non-conformal hydrodynamics from the relativistic Boltzmann equation. We demonstrate how constitutive relations for shear and bulk stresses can be transformed into dynamical evolution equations, resulting in Israel-Stewart-like (ISL) hydrodynamics. To understand the far-from-equilibrium applicability of such ISL theories, we investigate the one-dimensional boost-invariant Boltzmann equation using special moments of the distribution function for a system with finite particle mass. Our analysis reveals that the mathematical structure of the ISL equations is akin to that of moment equations, enabling them to approximately replicate even the collisionless dynamics. We conclude that this particular feature is important in extending the applicability of ISL theories beyond the hydrodynamic regime.
Comments:
Contribution to Quark Matter 2023 (4 pages)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2312.10254 [pdf]
EPJ Web Conf.(2024)·1 citation
06
[Submitted on 16 Dec 2023]
Symmetry-restored Skyrme-Random-Phase-Approximation calculations of the monopole strength in deformed nuclei
A. Porro · G. Colò · T. Duguet · D. Gambacurta · V. Somà
Within the Energy Density Functional (EDF) approach, the use of mean-field wave-functions deliberately breaking (some) symmetries of the underlying Hamiltonian is an efficient and largely utilized way to incorporate static correlations. However, the restoration of broken symmetries is eventually mandatory to recover the corresponding quantum numbers and to achieve a more precise description of nuclear properties. While symmetry-restored calculations are routinely performed to study ground-state properties and low-lying excitations, similar applications to the nuclear response are essentially limited to either formal studies or to schematic models. In the present paper, the effect of angular momentum restoration on the monopole and quadrupole responses of doubly open-shell nuclei is investigated. Based on deformed Skyrme-Random Phase Approximation (RPA) calculations, the exact Angular Momentum Projection (AMP) is implemented in the calculation of the multipole strength functions, thus defining a projection after variation (PAV-RPA) scheme. The method is employed for the first time in a realistic study to investigate the effect of AMP on the coupling of monopole and quadrupole modes in $^{24}$ Mg resulting from its intrinsic deformation.
Comments:
14 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.10410 [pdf]
PRC(2024)·8 citations
07
[Submitted on 16 Dec 2023]
Reply to the "Comment on `Effect of density and nucleon-nucleon potential on the fusion cross section within the relativistic mean field formalism'"
M. Bhuyan · Raj Kumar · Shilpa Rana · D. Jain · S. K. Patra · B. V. Carlson
In reply to the Comment made by M. V. Chushnyakova et al. on our paper [Phys. Rev. C 101, 044603 (2020)], we argue that the calculations, results and conclusions of our paper remain valid. We have shown here the calculations for one reaction using the deformed densities and the R3Y nucleon-nucleon potential obtained within the relativistic mean-field (RMF) formalism. Suitable clarications and justifications are given to address all the points raised in the Comment.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.10452 [pdf]
0 citations
08
[Submitted on 18 Dec 2023]
Benchmark of many-body approaches for magnetic dipole transition strength
M. Frosini🇫🇷 · W. Ryssens🇧🇪 · K. Sieja🇫🇷
The low-energy enhancement observed recently in the deexcitation gamma-ray strength functions, suggested to arise due to the magnetic dipole radiation, motivates theoretical efforts to improve the description of M1 strength in available nuclear structure models. Reliable theoretical predictions of nuclear dipole excitations are of interest for different nuclear applications and in particular for nuclear astrophysics, where the calculations of radiative capture cross sections often resort to theoretical strength functions. We aim to benchmark many-body methods in their description of the M1 strength functions, with a special emphasis on the low-energy effects observed in the deexcitation strength. We investigate the zero-temperature and finite-temperature magnetic dipole strength functions computed within the quasiparticle random-phase approximation and compare them to those from exact diagonalizations of the same Hamiltonian in restricted orbital spaces. The study is carried out for a sample of 25 spherical and deformed nuclei which can be described by diagonalization of the respective effective Hamiltonian in three different valence spaces. A reasonable agreement is found for the total photoabsorption strengths while the QRPA distributions are shown to be systematically shifted down in energy with respect to exact results. Photoemission strengths obtained within the FT-QRPA appear insufficient to explain the low-energy enhancement of the M1 strength functions. The problems encountered in QRPA calculations are ascribed to the lack of correlations in the nuclear ground state and to the truncation of the many-body space. In particular, the latter prevents obtaining the sufficiently high level density to produce the low-energy enhancement of the strength function, making the (FT-)QRPA approach unsuitable for predictions of such effects across the nuclear chart.
Comments:
15 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.11040 [pdf]
PRC(2024)·7 citations
09
[Submitted on 18 Dec 2023]
Simulating collectivity in dense baryon matter with multiple fluids
Jakub Cimerman🇨🇿 · Iurii Karpenko🇨🇿 · Boris Tomasik🇨🇿 · Pasi Huovinen🇵🇱
A novel three-fluid dynamical model for simulations of heavy-ion collisions at RHIC Beam Energy Scan programme, called MUFFIN, has been developed. The novelty consists of modular inclusion of the Equation of State, use of hyperbolic coordinates that allow to simulate higher collision energies, and fluctuating initial conditions. The model reproduces rapidity and $p_{t}$ spectra of collisions from $s_{N N}$ =7.7 to 62.4 GeV. Ideal fluid is assumed, and the elliptic flow is over-predicted, particularly at lower collision energies.
Comments:
Proceedings of Quark Matter 2023, 3-9 Sept. 2023, Houston, Texas, 4 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.11070 [pdf]
EPJ Web Conf.(2024)·0 citations
10
[Submitted on 18 Dec 2023]
Lattice-based equation of state with 3D Ising critical point
Micheal Kahangirwe · Steffen A. Bass · Johannes Jahan · Pierre Moreau · Paolo Parotto · Claudia Ratti · Olga Soloveva · Misha Stephanov · Elena Bratkovskaya
The BEST Collaboration equation of state combining lattice data with the 3D Ising critical point encounters limitations due to the truncated Taylor expansion up to $\frac{μ _{B}}{T} \sim 2.5$ . This truncation consequently restricts its applicability at high densities. Through a resummation scheme, the lattice results have been extended to $\frac{μ _{B}}{T} = 3.5$ . In this article, we amalgamate these ideas with the 3D-Ising model, yielding a family of equations of state valid up to $μ_{B} = 700 MeV$ with the correct critical behavior. Our equations of state feature tunable parameters, providing a stable and causal framework-a crucial tool for hydrodynamics simulations.
Comments:
4 pages, 2 figures, Contribution to Quark Matter2023 (Houston, TX, 3-9 Sep. 2023)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2312.11265 [pdf]
EPJ Web Conf.(2024)·3 citations
11
[Submitted on 18 Dec 2023]
Directed flow and hyperon polarization at RHIC BES from multi-fluid dynamics
Iurii Karpenko🇨🇿 · Jakub Cimerman🇨🇿
We present directed flow of protons and pions, as well as mean polarization of $Λ$ and $Λ ˉ$ hyperons computed for Au-Au collisions at $s_{NN} = 5...19.6$ GeV in MUFFIN model. MUlti Fluid simulation for Fast IoN collisions, or MUFFIN, is a state-of-the-art 3-fluid dynamic model for simulating heavy-ion collisions in the region from a few to a hundred GeV center-of-mass energy. Whereas MUFFIN succeeds to reproduce basic observables in the collision energy range of interest, the slope of the directed flow at mid-rapidity is much steeper as compared to the data, it has unclear EoS dependence and final-state hadronic cascade affects this observable significantly. The excitation function of the $Λ$ polarization shows a significant splitting between polarizations of $Λ$ and $Λ ˉ$ , which challenges a widespread interpretation that the splitting is affected mainly by the late-stage magnetic field.
Comments:
Contribution to the proceedings of Quark Matter 2023 conference (Houston, TX, 3-9 September 2023). 4 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.11325 [pdf]
EPJ Web Conf.(2024)·3 citations
12
[Submitted on 18 Dec 2023]
Holographic transport coefficients and jet energy loss for the hot and dense quark-gluon plasma
Joaquin Grefa🇺🇸 · Mauricio Hippert🇺🇸 · Raghav Kunnawalkam Elayavalli🇺🇸 · Jacquelyn Noronha-Hostler🇺🇸 · Israel Portillo🇺🇸 · Claudia Ratti🇺🇸 · Romulo Rougemont🇧🇷
We employ an Einstein-Maxwell-dilaton model, based on the gauge/gravity correspondence, to obtain the thermodynamics and transport properties for the hot and dense quark-gluon plasma. The model, which is constrained to reproduce lattice QCD thermodynamics at zero density, predicts a critical point and a first order line at finite temperature and density, is used to quantify jet energy loss through simulations of high-energy collision events.
Comments:
4 pages, 2 figures. Contribution to the proceedings of Quark Matter 2023
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex)
arXiv:
2312.11449 [pdf]
EPJ Web Conf.(2024)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE