Nuclear Theory·nucl-th

Monday·February 28, 2022

10 papers—3 primary·7 cross-listed

01
Constraints on the Lambda-neutron interaction from charge-symmetry breaking of A=4 hypernuclei
Andreas Nogga🇩🇪 · Johann Haidenbauer🇩🇪 · Ulf-G. Meißner🇩🇪
We include the leading charge symmetry breaking contributions into the hyperon-nucleon interactions derived within chiral effective field theory up to next-to-leading order. Two low energy constants are determined using the experimentally known differences of Lambda separation energies of 4-Lambda-He and 4-Lambda-H. This allows one to predict the Lambda-neutron scattering lengths for the first time based on data. Various sources of uncertainty are discussed.
nucl-thPoS(2024)·0 citations
02
Canonical and phenomenological formulations of spin hydrodynamics
Asaad Daher🇵🇱 · Arpan Das🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱
Two formulations of relativistic hydrodynamics of particles with spin 1/2 are compared. The first approach, dubbed the canonical one, uses expressions for the energy-momentum and spin tensors that have properties that follow a direct application of Noether's theorem, which yields a totally antisymmetric spin tensor. The other one is based on a simplified form of the spin tensor and is commonly used in the current literature under the name of a phenomenological approach. We show that these two frameworks are equivalent, i.e., they can be directly connected by a suitably defined pseudogauge transformation, only if the first framework is initially improved by a suitable modification of the energy-momentum tensor (addition of a divergence-free term that cannot be interpreted as a pseudogauge). Our analysis uses arguments related to the positivity of entropy production. The latter turns out to be equivalent for the improved canonical and phenomenological frameworks.
nucl-thhep-phPRC(2023)·65 citations
03
Hadronization and Color Transparency
Kai gallmeister🇩🇪 · Ulrich Mosel🇩🇪
In this article we review our work on the production of hadrons in the nuclear environment. We work with a string-breaking model for the initial production of hadrons and with a quantum-kinetic transport model (GiBUU) to describe the final state interactions of the newly formed (pre)hadrons. The latter are determined both by the formation times and by the time-development of the hadron-hadron cross section. We first show that only a linear time-dependence is able to describe the available hadronization data. We then compare with detailed data from HERMES and JLAB; very good agreement is reached in all reactions studied without any tuning of parameters. We also repeat predictions of spectra for pions and kaons at JLAB@12GeV. We finally explain the absence of CT effects in the recent experiment on proton transparencies in quasielastic (QE) events on nuclei. We propose to look instead for CT effects on protons in semi-inclusive DIS (SIDIS) events.
nucl-thhep-exhep-phnucl-exMDPI Physics(2022)·5 citations
04
Gauge dependence of the quark gap equation: an exploratory study
José Roberto Lessa🇧🇷 · Fernando E. Serna🇧🇷 · Bruno El-Bennich🇧🇷 · Adnan Bashir🇲🇽 · Orlando Oliveira🇵🇹
We study the gauge dependence of the quark propagator in quantum chromodynamics by solving the gap equation with a nonperturbative quark-gluon vertex which is constrained by longitudinal and transverse Slavnov-Taylor identities, the discrete charge conjugation and parity symmetries and which is free of kinematic singularities in the limit of equal incoming and outgoing quark momenta. We employ gluon propagators in renormalizable $R_{ξ}$ gauges obtained in lattice QCD studies. We report the dependence of the nonperturbative quark propagator on the gauge parameter, in particular we observe an increase, proportional to the gauge-fixing parameter, of the mass function in the infrared domain, whereas the wave renormalization decreases within the range $0 \leq ξ \leq 1$ considered here. The chiral quark condensate reveals a mild gauge dependence in the region of $ξ$ investigated. We comment on how to build and improve upon this exploratory study in future in conjunction with generalized gauge covariance relations for QCD.
↳ hep-phhep-latnucl-thPRD(2023)·20 citations
05
Basic Elements for Simulations of Standard Model Physics with Quantum Annealers: Multigrid and Clock States
Marc Illa🇺🇸 · Martin J. Savage🇺🇸
We explore the potential of D-Wave's quantum annealers for computing some of the basic components required for quantum simulations of Standard Model physics. By implementing a basic multigrid (including "zooming") and specializing Feynman-clock algorithms, D-Wave's Advantage is used to study harmonic and anharmonic oscillators relevant for lattice scalar field theories and effective field theories, the time evolution of a single plaquette of SU(3) Yang-Mills lattice gauge field theory, and the dynamics of flavor entanglement in four neutrino systems.
↳ quant-phhep-lathep-phnucl-thPRA(2022)·73 citations
06
Friedel formula and Krein's theorem in complex potential scattering theory
Peng Guo🇺🇸 · Vladimir Gasparian🇺🇸
In this work, the generalization of Friedel formula and Krein's theorem in complex potential scattering theory is presented. The consequence of various symmetry constraints on dynamical system are discussed. In addition, Muskhelishvili-Omnès representation of Krein's theorem is also given and discussed.
↳ cond-mat.otherhep-phnucl-thPRResearch(2022)·14 citations
07
Nuclear force with LapH smearing
Takuya Sugiura🇯🇵 · Yutaro Akahoshi🇯🇵 · Tatsumi Aoyama🇯🇵 · Takahiro M. Doi🇯🇵 · Takumi Doi🇯🇵
The nuclear forces are determined by combining the HAL QCD method and a new type of source smearing technique. The new smearing is a projection to a space spanned by the lowest-lying eigenvectors of the free Laplacian operator on a lattice, which enables efficient calculation of hadron correlators at an affordable cost by utilizing the hadron-level momentum conservations. We find that this new approach reduces the statistical and systematic errors in the resultant nuclear forces.
↳ hep-lathep-phnucl-thPoS(2022)·2 citations
08
Four-body system of $^{4} He$ atoms: Dimer-dimer scattering
A. Deltuva
The strong short-range repulsion, characteristic to realistic interatomic potentials, complicates the description of weakly-bound few-body systems such as those of \He atoms. The present work proposes an approach for solving this problem and applies it to a realistic system of four $^{4} He$ atoms. The potential is gradually softened such that rigorous four-body equations for bound and scattering tates can be accurately solved in the momentum-space framework, and the results are extrapolated back to the limit of the original potential. Linear correlations between three- and four body quantities are observed, and the accuracy of the procedure is improved by extrapolating in one of the three-body quantities. Results for the $^{4} He$ tetramer ground and excited state binding energies and atom-trimer scattering agree well with at least some of earlier determinations and shed light on the existing disagreements. An additional case of the Phillips correlation line is established for the dimer-dimer scattering length. The trimer production rate via the ultracold two-dimer collisions is estimated, it exhibits significant finite-range effects despite the weak binding of the dimer.
↳ physics.atom-phcond-mat.quant-gasnucl-thPRA(2022)·3 citations
09
In-beam $γ$ -ray spectroscopy of $^{32}$ Mg via direct reactions
N. Kitamura🇯🇵 · K. Wimmer🇪🇸 · T. Miyagi🇨🇦 · A. Poves🇪🇸 · N. Shimizu🇯🇵 · J. A. Tostevin🇬🇧 · V. M. Bader🇺🇸 · C. Bancroft🇺🇸 · D. Barofsky🇺🇸 · T. Baugher🇺🇸 · D. Bazin🇺🇸 · J. S. Berryman🇺🇸 and 17 other authors
Background: The nucleus $^{32}$ Mg ( $N = 20$ and $Z = 12$ ) plays a central role in the so-called "island of inversion" where in the ground states $s d$ -shell neutrons are promoted to the $f p$ -shell orbitals across the shell gap, resulting in the disappearance of the canonical neutron magic number $N = 20$ . Purpose: The primary goals of this work are to extend the level scheme of $^{32}$ Mg, provide spin-parity assignments to excited states, and discuss the microscopic structure of each state through comparisons with theoretical calculations. Method: In-beam $γ$ -ray spectroscopy of $^{32}$ Mg was performed using two direct-reaction probes, one-neutron (two-proton) knockout reactions on $^{33}$ Mg ( $^{34}$ Si). Final-state exclusive cross sections and parallel momentum distributions were extracted from the experimental data and compared with eikonal-based reaction model calculations combined with shell-model overlap functions. Results: Owing to the remarkable selectivity of the one-neutron and two-proton knockout reactions, a significantly updated level scheme for $^{32}$ Mg, which exhibits negative-parity intruder and positive-parity normal states, was constructed. The experimental results were confronted with four different nuclear structure models. Conclusions: In some of these models, different aspects of $^{32}$ Mg and the transition into the island of inversion are well described. However, unexplained discrepancies remain, and even with the help of these state-of-the-art theoretical approaches, the structure of this key nucleus is not yet fully captured.
↳ nucl-exnucl-thPRC(2022)·7 citations
10
Neutron stars and phase diagram in a hard-wall AdS/QCD model
Lorenzo Bartolini🇨🇳 · Sven Bjarke Gudnason🇨🇳 · Josef Leutgeb🇦🇹 · Anton Rebhan🇦🇹
We study the phase diagram of (large- $N_{c}$ ) QCD using a simplistic holographic hard-wall model with a dynamical scalar field and a homogeneous Ansatz representing a smeared instanton/baryon density. The resulting phase diagram is qualitatively consistent with expectations, including a mesonic, baryonic, quarkyonic, and quark-gluon plasma phase. As in other holographic models, we also find a baryonic popcorn transition, which appears at large chemical potential as a crossover. We then evaluate the nuclear matter equation of state, which turns out to be rather stiff with a large peaked sound velocity above the conformal limit, construct corresponding neutron stars using the TOV equations, and finally use a full numerical gravity/hydrodynamics computation to extract the gravitational wave signal of neutron star mergers.
↳ hep-thastro-ph.HEhep-phnucl-thPRD(2022)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE