Nuclear Theory·nucl-th

Tuesday·February 20, 2024

15 papers—6 primary·9 cross-listed

07
Exploiting symmetries in nuclear Hamiltonians for ground state preparation
Joe Gibbs🇬🇧 · Zoë Holmes🇨🇭 · Paul Stevenson🇬🇧
The Lipkin and Agassi models are simplified nuclear models that provide natural test beds for quantum simulation methods. Prior work has investigated the suitability of the Variational Quantum Eigensolver (VQE) to find the ground state of these models. There is a growing awareness that if VQE is to prove viable, we will need problem inspired ansätze that take into account the symmetry properties of the problem and use clever initialization strategies. Here, by focusing on the Lipkin and Agassi models, we investigate how to do this in the context of nuclear physics ground state problems. We further use our observations to discus the potential of new classical, but quantum-inspired, approaches to learning ground states in nuclear problems.
↳ quant-phnucl-thQuantum Machine Intelligence(2025)·19 citations
08
In-medium static inter-quark potential on high resolution quenched lattices
Rasmus N. Larsen🇳🇴 · Gaurang Parkar🇳🇴 · Alexander Rothkopf🇳🇴 · Johannes Heinrich Weber🇳🇴
We re-investigate the interactions between static color sources in a finite temperature gluonic medium using both high resolution isotropic and anisotropic quenched lattice QCD ensembles. The underlying ill-posed inverse problem, related to the extraction of spectral functions, is attacked with a range of different methods, including Bayesian inference, Padé interpolation and model fits. Among the latter we include a tail amended Gaussian ansatz and a HTL-inspired fit ansatz. We reconfirm the presence of a dominant low-lying spectral feature that supports the existence of a potential picture for the in-medium evolution of the static charges at late real times. Using the raw unmodified lattice data, all applicable methods show clear signs of screening of the real-part of the potential. After applying a subtraction procedure featured in a previous study we find however that screening disappears from the extracted potential. Paths towards the resolution of this puzzle are discussed.
↳ hep-lathep-phnucl-thPRD(2024)·9 citations
09
Global Fit of Electron and Neutrino Elastic Scattering Data to Determine the Strange Quark Contribution to the Vector and Axial Form Factors of the Nucleon
S.F. Pate🇺🇸 · V. Papavassiliou🇺🇸 · J.P. Schaub🇺🇸 · D.P. Trujillo🇺🇸 · M.V. Ivanov🇧🇬 · M.B. Barbaro🇮🇹 · C. Giusti🇮🇹
We present a global fit of neutral-current elastic (NCE) neutrino-scattering data and parity-violating electron-scattering (PVES) data with the goal of determining the strange quark contribution to the vector and axial form factors of the proton. Previous fits of this form included data from a variety of PVES experiments (PVA4, HAPPEx, G0, SAMPLE) and the NCE neutrino and anti-neutrino data from BNL E734. These fits did not constrain the strangeness contribution to the axial form factor $G_{A}^{s} (Q^{2})$ at low $Q^{2}$ very well because there was no NCE data for $Q^{2} < 0.45$ GeV $^{2}$ . Our new fit includes for the first time MiniBooNE NCE data from both neutrino and anti-neutrino scattering; this experiment used a hydrocarbon target and so a model of the neutrino interaction with the carbon nucleus was required. Three different nuclear models have been employed: a relativistic Fermi gas model, the SuperScaling Approximation model, and a spectral function model. We find a tremendous improvement in the constraint of $G_{A}^{s} (Q^{2})$ at low $Q^{2}$ compared to previous work, although more data is needed from NCE measurements that focus on exclusive single-proton final states, for example from MicroBooNE.
↳ hep-phhep-exnucl-exnucl-thPRD(2024)·12 citations
10
Prompt Black Hole Formation in Binary Neutron Star Mergers
Christian Ecker🇩🇪 · Konrad Topolski🇩🇪 · Matti Järvinen🇰🇷 · Alina Stehr🇩🇪
We carry out an in-depth analysis of the prompt-collapse behaviour of binary neutron star (BNS) mergers. To this end, we perform more than $80$ general relativistic BNS merger simulations using a family of realistic Equations of State (EOS) with different stiffness, which feature a first order deconfinement phase transition between hadronic and quark matter. From these simulations we infer the critical binary mass $M_{crit}$ that separates the prompt from the non-prompt collapse regime. We show that the critical mass increases with the stiffness of the EOS and obeys a tight quasi-universal relation, $M_{crit} / M_{TOV} \approx 1.41 \pm 0.06$ , which links it to the maximum mass $M_{TOV}$ of static neutron stars, and therefore provides a straightforward estimate for the total binary mass beyond which prompt collapse becomes inevitable. In addition, we introduce a novel gauge independent definition for a one-parameter family of threshold masses in terms of curvature invariants of the Riemann tensor which characterizes the development toward a more rapid collapse with increasing binary mass. Using these diagnostics, we find that the amount of matter remaining outside the black hole sharply drops in supercritical mass mergers compared to subcritical ones and is further reduced in mergers where the black hole collapse is induced by the formation of a quark matter core. This implies that $M_{crit}$ , particularly for merger remnants featuring quark matter cores, imposes a strict upper limit on the emission of any detectable electromagnetic counterpart in BNS mergers.
↳ astro-ph.HEgr-qchep-phnucl-thPRD(2025)·23 citations
11
QCD Kondo effect for single heavy quark in chiral-symmetry broken phase
Shigehiro Yasui🇯🇵 · Daiki Suenaga🇯🇵 · Kei Suzuki🇯🇵
We consider the quantum chromodynamics (QCD) Kondo effect for a single heavy quark in quark matter composed of light quarks with chiral symmetry breaking. Introducing several spinor structures in QCD Kondo condensates, i.e., particle-projected condensate, antiparticle-projected condensate, and normal condensate without projection, we calculate the attractive energy gained by the heavy quark within the mean-field approximation in the path-integral formalism. We show that the normal condensate is favored at low density and the particle-projected condensate is favored at high density, when the light quark has a nonzero mass. We interpret such a density-dependent transition between the two condensates in terms of the Kondo resonances.
↳ hep-phcond-mat.str-elnucl-thPRD(2024)·1 citation
12
Lattice QCD and Baryon-Baryon Interactions
Sinya Aoki🇯🇵 · Takumi Doi🇯🇵
In this chapter, the current status on baryon-baryon interactions such as nuclear forces in lattice Quantum ChromoDynamics (QCD) is reviewed. In studies of baryon-baryon interactions in lattice QCD, the most reliable method so far is the potential method, proposed by the Hadrons to Atomic nuclei from Lattice QCD (HAL QCD) collaboration, whose formulation, properties and extensions are explained in detail. Using the HAL QCD potential method, potentials between nucleons (proton and neutron, denoted by $N$ ) in the derivative expansion have been extracted in various cases. The lattice QCD results shown in this chapter include a Leading Order (LO) central potential in the parity-even $N N (^{1} S_{0})$ channel, LO central and tensor potentials in the parity-even $N N (^{3} S_{1}$ - $^{3} D_{1})$ channel, and a Next-to-Leading Order (NLO) spin-orbit potential as well as LO potentials in the parity-odd channels. Preliminary results at the almost physical pion and kaon masses, in addition to exploratory studies on three-nucleon potentials, are presented. Interactions between generic baryons including hyperons, made of one or more strange quarks as well as up and down quarks, have also been investigated. Universal properties of potentials between baryons become manifest in the flavor SU(3) symmetric limit, where masses of three quarks, up, down and strange, are all equal. In particular, it is observed that one bound state, traditionally called the $H$ -dibaryon, appears in the flavor singlet representation of SU(3). A fate of the $H$ dibaryon is also discussed with flavor SU(3) breaking taken into account at the almost physical point. Finally, various kinds of dibaryons, bound or resonate states of two baryons, including charmed dibaryons, have been predicted by lattice QCD simulations at the almost physical point.
↳ hep-lathep-phnucl-th"Handbook of Nuclear Physics" (Springer, …·11 citations
13
Precision mass measurements in the zirconium region pin down the mass surface across the neutron midshell at $N = 66$
M. Hukkanen🇫🇮 · W. Ryssens🇧🇪 · P. Ascher🇫🇷 · M. Bender🇫🇷 · T. Eronen🇫🇮 · S. Grévy🇫🇷 · A. Kankainen🇫🇮 · M. Stryjczyk🇫🇮 · O. Beliuskina🇫🇮 · Z. Ge🇫🇮 · S. Geldhof🇧🇪 · M. Gerbaux🇫🇷 and 10 other authors
Precision mass measurements of $^{104}$ Y, $^{106}$ Zr, $^{104, 104 m, 109}$ Nb, and $^{111, 112}$ Mo have been performed with the JYFLTRAP double Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line facility. The order of the long-lived states in $^{104}$ Nb was unambiguously established. The trend in two-neutron separation energies around the $N = 66$ neutron midshell appeared to be steeper with respect to the Atomic Mass Evaluation 2020 extrapolations for the $_{39}$ Y and $_{40}$ Zr isotopic chains and less steep for the $_{41}$ Nb chain, indicating a possible gap opening around $Z = 40$ . The experimental results were compared to the BSkG2 model calculations performed with and without vibrational and rotational corrections. All of them predict two low-lying minima for $^{106}$ Zr. While the unaltered BSkG2 model fails to predict the trend in two-neutron separation energies, selecting the more deformed minima in calculations and removing the vibrational correction, the calculations are more in line with experimental data. The same is also true for the $2_{1}^{+}$ excitation energies and differences in charge radii in the Zr isotopes. The results stress the importance of improved treatment of collective corrections in large-scale models and further development of beyond-mean-field techniques.
↳ nucl-exnucl-thPLB(2024)·16 citations
14
Electroweak three-body decays in the presence of two- and three-body bound states
Raul A. Briceño🇺🇸 · Andrew Jackura🇺🇸 · Dimitra A. Pefkou🇺🇸 · Fernando Romero-López🇺🇸
Recently, formalism has been derived for studying electroweak transition amplitudes for three-body systems both in infinite and finite volumes. The formalism provides exact relations that the infinite-volume amplitudes must satisfy, as well as a relationship between physical amplitudes and finite-volume matrix elements, which can be constrained from lattice QCD calculations. This formalism poses additional challenges when compared with the analogous well-studied two-body equivalent one, including the necessary step of solving integral equations of singular functions. In this work, we provide some non-trivial analytical and numerical tests on the aforementioned formalism. In particular, we consider a case where the three-particle system can have three-body bound states as well as bound states in the two-body subsystem. For kinematics below the three-body threshold, we demonstrate that the scattering amplitudes satisfy unitarity. We also check that for these kinematics the finite-volume matrix elements are accurately described by the formalism for two-body systems up to exponentially suppressed corrections. Finally, we verify that in the case of the three-body bound state, the finite-volume matrix element is equal to the infinite-volume coupling of the bound state, up to exponentially suppressed errors.
↳ hep-lathep-phnucl-thJHEP(2024)·10 citations
15
Simultaneous reweighting of Transverse Momentum Dependent distributions
Mariaelena Boglione🇮🇹 · Umberto D'Alesio🇮🇹 · Carlo Flore🇮🇹 · Josè Osvaldo Gonzalez-Hernandez🇮🇹 · Francesco Murgia🇮🇹 · Alexei Prokudin🇺🇸
The Bayesian reweighting procedure is extended to the case of multiple independent extractions of transverse momentum dependent parton distributions (TMDs). By exploiting the data on transverse single spin asymmetries, $A_{N}$ , for inclusive pion production in polarized proton-proton collisions measured at RHIC, we perform a simultaneous reweighting of the quark Sivers, transversity and Collins TMD functions extracted from semi-inclusive deep inelastic scattering (SIDIS) and $e^{+} e^{-}$ annihilation into hadron pairs. The impact of the implementation of the Soffer bound, as well as the differences between older and newer $A_{N}$ data, are investigated. The agreement with $A_{N}$ data at large- $x_{F}$ values, a kinematical region complementary to those explored in SIDIS measurements, is enhanced, improving the knowledge of the polarized quark TMDs in the large- $x$ region.
↳ hep-phhep-exhep-thnucl-thPLB(2024)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE