Nuclear Theory·nucl-th

Monday·April 25, 2022

6 papers—4 primary·2 cross-listed

01
Path Integral Quantum Monte Carlo Calculations of Light Nuclei
Rong Chen · Kevin E. Schmidt
We describe a path-integral ground-state quantum Monte Carlo method for light nuclei in continuous space. We show how to efficiently update and sample the paths with spin-isospin dependent and spin-orbit interactions. We apply the method to the triton and alpha particle using both local chiral interactions with next-to-next-to-leading-order %(N $^{2}$ LO) and the Argonne interactions. For operators, like the total energy, that commute with the Hamiltonian, our results agree with Green's function Monte Carlo and auxiliary field diffusion Monte Carlo calculations. For operators that do not commute with the Hamiltonian and for Euclidean response functions, the path-integral formulation allows straightforward calculation without forward walking or the increased variance typical of diffusion methods. We demonstrate this by calculating density distributions, root mean square radii, and Euclidean response functions for single-nucleon couplings.
nucl-thPRC(2022)·3 citations
02
Extraction of different temperatures and kinetic freeze-out volume in high energy collisions
M. Waqas🇨🇳 · G.-X. Peng🇨🇳 · M. Ajaz🇵🇰 · A. Haj Ismail🇮🇳 · Z. Wazir🇵🇰 · L.-L. Li🇨🇳
We analyze the transverse momentum ( $p_{T}$ ) spectra, $1/ N_{e v}$ [(1/2 $π$ $p_{T}$ ) $d^{2}$ $N$ / $d y d$ $p_{T}$ ], of kaon, proton, deuteron and triton in different centrality events in gold-gold (Au-Au) collisions at Relativistic Heavy Ion Collisions (RHIC) by Hagedorn thermal model and extracted the excitation function of effective temperature, kinetic freeze-out volume, initial temperature and kinetic freeze-out temperature. We perceived that the effective temperature, initial temperature and kinetic freeze-out temperature sharply increases from 7.7 GeV to 14.5 GeV and then remain static from 14.5-39 GeV, and this consistency may disclose that the onset energy of the phase transition of partial deconfinement and the whole deconfinement are 14.5 and 39 GeV respectively. The kinetic freeze-out volume and mean transverse momentum grows with the rise of collision energy. Furthermore, the different extracted temperatures are observed in the order of time evolution of the interacting system, and they (as well as kinetic freeze-out volume) have an increasing trend from peripheral to central collisions. We also observed the mass dependence of the effective temperature and kinetic freeze-out volume where former increases while the later decreases for heavier particles, which indicates the early freeze-out of the heavier particles.
nucl-thhep-phJ.Phys.G(2022)·21 citations
03
Nuclear spectra from low-energy interactions
J. Ljungberg · B. G. Carlsson · J. Rotureau · A. Idini · I. Ragnarsson
A method to describe spectra starting from nuclear density functionals is explored. The idea is based on postulating an effective Hamiltonian that reproduces the stiffness associated with collective modes. The method defines a simple form of such an effective Hamiltonian and a mapping to go from a density functional to the corresponding Hamiltonian. In order to test the method, the Hamiltonian is constrained using a Skyrme functional and solved with the generator-coordinate method to describe low-lying levels and electromagnetic transitions in $^{48, 49, 50, 52}$ Cr and $^{24}$ Mg.
nucl-thPRC(2022)·9 citations
04
Energy Dependent Model of Isotopic Production Cross Sections from Proton- $^{16}$ O Interactions
Francis A. Cucinotta · Sungmin Pak
Proton interactions with $^{16}$ O nuclei are the most frequent nuclear interaction leading to secondary radiation in tissues for space radiation and cancer therapy with protons. In addition, $^{16}$ O has the largest fluence of galactic cosmic rays, and interacts with hydrogen in tissue or water and polyethylene shielding. The fragmentation of oxygen produces a large number of heavy ion (A>4) target fragments (TF) with high ionization density. Here we develop an analytical model of energy dependent proton- $^{16}$ O cross sections. We introduce corrections to measurements of total charge changing cross sections to extend data on nuclear absorption cross sections. Using experimental data and a 2nd order optical model an accurate formula for the p- $^{16}$ O absorption cross section from <10 MeV/n to >10 GeV/N is obtained. The energy dependence of the isotopic cross sections is modeled as multiplicities scaled to absorption cross section resulting in an accurate model over the full energy range.
nucl-th0 citations
05
The Role of the Hadron-Quark Phase Transition in Core-Collapse Supernovae
Pia Jakobus🇦🇺 · Bernhard Mueller🇦🇺 · Alexander Heger🇦🇺 · Anton Motornenko🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪
The hadron-quark phase transition in quantum chromodyanmics has been suggested as an alternative explosion mechanism for core-collapse supernovae. We study the impact of three different hadron-quark equations of state (EoS) with first-order (DD2F\_SF, STOS-B145) and second-order (CMF) phase transitions on supernova dynamics by performing 97 simulations for solar- and zero-metallicity progenitors in the range of $14 - 100 M_{⊙}$ . We find explosions only for two low-compactness models ( $14 M_{⊙}$ and $16 M_{⊙}$ ) with the DD2F\_SF EoS, both with low explosion energies of $\sim 1 0^{50} erg$ . These weak explosions are characterised by a neutrino signal with several mini-bursts in the explosion phase due to complex reverse shock dynamics, in addition to the typical second neutrino burst for phase-transition driven explosions. The nucleosynthesis shows significant overproduction of nuclei such as $^{90} Zr$ for the $14 M_{⊙}$ zero-metallicity model and $^{94} Zr$ for the $16 M_{⊙}$ solar-metallicity model, but the overproduction factors are not large enough to place constraints on the occurrence of such explosions. Several other low-compactness models using the DD2F\_SF EoS and two high-compactness models using the STOS EoS end up as failed explosions and emit a second neutrino burst. For the CMF EoS, the phase transition never leads to a second bounce and explosion. For all three EoS, inverted convection occurs deep in the core of the proto-compact star due to anomalous behaviour of thermodynamic derivatives in the mixed phase, which heats the core to entropies up to $4 k_{B} / baryon$ and may have a distinctive gravitational wave signature, also for a second-order phase transition.
↳ astro-ph.HEastro-ph.SRnucl-thMNRAS(2022)·46 citations
06
Chirality distributions inside baryons in $QC D_{2}$
Adrien Florio🇺🇸 · David Frenklakh🇺🇸 · Dmitri E. Kharzeev🇺🇸
The connection between the spin distribution and the topological structure of the baryon is an open and important problem. Here we address it using QCD in $(1 + 1)$ spacetime dimensions, which is exactly solvable at large number of colors $N$ . It is found that the distribution of chirality inside a baryon is drastically different from a chirality distribution inside states with zero baryon number, ``mesons". This difference is shown to arise from the topological structure of the baryon -- at large $N$ , all of the baryon's chirality is concentrated near $x = 0$ , whereas in a meson state it vanishes in the small $x$ limit. Our results illustrate how the constituent features of the baryon reemerge and are tied to the topological features of the bosonized solitonic solution. Possible implications for QCD in $(3 + 1)$ dimensions and for deep inelastic scattering experiments are discussed.
↳ hep-phhep-thnucl-thPRD(2022)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Path Integral Quantum Monte Carlo Calculations of Light Nuclei

Extraction of different temperatures and kinetic freeze-out volume in high energy collisions

Nuclear spectra from low-energy interactions

Energy Dependent Model of Isotopic Production Cross Sections from Proton-16O Interactions

The Role of the Hadron-Quark Phase Transition in Core-Collapse Supernovae

Chirality distributions inside baryons in QCD2​

Affiliations

Energy Dependent Model of Isotopic Production Cross Sections from Proton- $^{16}$ O Interactions

Chirality distributions inside baryons in $QC D_{2}$