Nuclear Theory·nucl-th

Wednesday·May 17, 2023

15 papers—10 primary·5 cross-listed

01
On cancellation of non-adiabatic and off-shell effects in the antiproton annihilation in deuteron
O.D. Dalkarov🇷🇺 · V.A. Karmanov🇷🇺 · E.A. Kupriyanova🇷🇺
As known, some approximate approaches to the hadron scattering from nuclei work rather well far beyond the limits of their applicability. This was explained by cancellation of the contributions (non-adiabatic and off-shell effects) omitted in these approaches. Moreover, in some cases (in particular, for the reaction $p ˉ d \to e^{+} e^{-} n$ ) this cancellation allowed to derive rather simple analytical formula for the reaction amplitude. Solving the Faddeev equations, we confirm numerically this formula and, hence, the cancellations.
nucl-thhep-phEPJA(2023)·0 citations
02
Global spin alignment of vector mesons and strong force fields in heavy- ion collisions
Jinhui Chen🇨🇳 · Zuo-Tang Liang🇨🇳 · Yu-Gang Ma🇨🇳 · Qun Wang🇨🇳
A perspective for the Global spin alignment of vector mesons and strong force fields in heavy-ion collisions is provided in this short report.
nucl-thhep-phnucl-exSci.Bull.(2023)·42 citations
03
Statistical approach of nuclear multifragmentation with realistic nuclear equation of state
S. Mallik
In this work, Canonical Thermodynamical model for nuclear multifragmentation has been updated with realistic nuclear equation of state. Mass distribution, intermediate mass fragment multiplicity as well as isospin sensitive observables have been investigated with semi-microscopic approach of determining nuclear binding and excitation energies. Production of neutron rich isotopes as well as isoscaling and isobaric yield ratio parameters have been significantly modified due to inclusion of this realistic nuclear equation of state.
nucl-thnucl-exPRC(2023)·4 citations
04
Evidence of bicluster structure in the ground state of $^{20}$ Ne
Y. Yamaguchi · W. Horiuchi · N. Itagaki
We explore the structure of the ground state of $^{20}$ Ne by investigating various density profiles. Four candidates for the ground state configurations, (a) $j$ - $j$ coupling and (b) SU(3) shell model and (c) $5 α$ and (d) $^{16} O + α$ cluster model configurations are generated by utilizing the antisymmetrized quasicluster model. A high-energy reaction theory, the Glauber model, relates these one-body density distributions and reaction observables. The angular distributions of the elastic scattering cross sections clearly distinguish these configurations and tell which is the most plausible one: The ground state of $^{20}$ Ne favors a 16+4 nucleon bi-cluster structure. A comprehensive investigation of other electric observables also supports this conclusion.
nucl-thPRC(2023)·12 citations
05
Odd-even shape staggering and kink structure of charge radii of Hg isotopes by the deformed relativistic Hartree-Bogoliubov theory in continuum
Myeong-Hwan Mun · Seonghyun Kim · W. Y. So · Soonchul Choi · Eunja Ha · Myung-Ki Cheoun
We examined the shape staggering of relative charge radii in $^{180 - 186}$ Hg isotopes, which was first measured in 1977 and recently confirmed using advanced spectroscopy techniques. To understand the nuclear structure underlying this phenomenon, we employed the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). Our analysis revealed that the shape staggering can be attributed to nuclear shape transition in the Hg isotopes. Specifically, we demonstrated that prolate shapes of $^{181, 183, 185}$ Hg lead to an increase in the charge radii compared to oblate shapes of $^{180, 182, 184, 186}$ Hg isotopes. We explained the nuclear shape staggering in terms of the evolution of occupation probability (OP) of $ν 1 i_{13/2}$ , $ν 1 h_{9/2}$ , $π 1 h_{9/2}$ , and $π 3 s_{1/2}$ states. Additionally, we clarified the kink structure of the charge radii in the Hg isotopes near $N = 126$ magic shell does not come from the change of the OP of $π 1 h_{9/2}$ state, but mainly by the increase of the OPs of $ν 1 i_{11/2}$ and $ν 2 g_{9/2}$ states.
nucl-thPLB(2023)·30 citations
06
Production of nuclei and hypernuclei in pion-induced reactions near threshold energies
Apiwit Kittiratpattana🇩🇪 · Tom Reichert🇩🇪 · Nihal Buyukcizmeci🇹🇷 · Alexander Botvina🇩🇪 · Ayut Limphirat🇹🇭 · Christoph Herold🇹🇭 · Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪
The Ultra-relativistic Quantum Molecular Dynamics model is employed to simulate $π^{-} + C$ and $π^{-} + W$ collisions at p $_{lab} = 1.7$ GeV motivated by the recent HADES results. By comparing the proton and $Λ$ transverse momentum spectra, it was observed that the data and transport model calculation show a good agreement, if cluster formation is included to obtain the free proton spectra. Predictions of light cluster ( $d$ , $t$ , $^{3}$ He, $^{4}$ He, as well as $_{Λ}^{3}$ H and $Ξ$ N) multiplicities and spectra are made using a coalescence mechanism. The resulting multiplicities suggest that the pion beam experiment can produce a substantial amount of $_{Λ}^{3}$ H, especially in $π^{-} + W$ collisions due to the stopping of the $Λ$ inside the large tungsten nucleus. The findings are supplemented by a statistical multi-fragmentation analysis suggesting that even larger hyper-fragments are produced copiously. It is suggested that even double strange hypernuclei are in reach and might be studied in more detail using a slightly higher pion beam momentum.
nucl-thhep-phPRC(2024)·5 citations
07
Configuration mixing and intertwined quantum phase transitions in odd-mass niobium isotopes
N. Gavrielov
Nuclei in the $Z \approx 40, N \approx 60$ region have one of the most complicated structural evolution across the nuclear chart, with coexisting shapes arising from different mixed configurations. In such a region, it is difficult to investigate odd-mass nuclei. In this paper a new algebraic framework is introduced, the interacting boson-fermion model with configuration mixing. Using this framework, with a boson core and a proton in the $1 f_{5/2}, 2 p_{3/2}, 2 p_{1/2}, 1 g_{9/2}$ orbits, a calculation is carried out to understand the structural evolution of the odd-mass niobium isotopes $(Z = 41)$ with neutron number 52-62. The calculated results are compared to energy levels, two neutron separation energies, $E 2$ and $M 1$ transition rates, and to quadrupole and magnetic moments. The detailed analysis discloses the effects of an abrupt crossing of states between normal and intruder configurations (Type II QPT), which is accompanied by a gradual evolution from spherical- to deformed-core shapes within the intruder configuration (Type I QPT), where both types of QPTs occur around the critical point of neutron number 60. The identification of both types of QPTs in the same chain of isotopes provides an empirical manifestation of intertwined quantum phase transitions (IQPTs) in odd-mass nuclei and the relevance of IQPTs to the niobium chain.
nucl-thPRC(2023)·18 citations
08
Synthesis of elements in compact stars in pycnonuclear reactions with Carbon isotopes: Quasibound states versus states of zero-points vibrations
Sergei P. Maydanyuk (1,2) · Gyorgy Wolf (1) · Kostiantyn A. Shaulskyi (2) ((1) Wigner Research Center for Physics, Budapest, Hungary, (2) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine)
(1) Purpose: Conditions of formation of compound nuclear system needed for synthesis of heavy nuclei in pycnonuclear reactions in compact stars are studied on a quantum mechanical basis. (2) Methods: Method of multiple internal reflections is generalized for pycnoreactions in compact stars with new calculations of quasibound spectra and spectra of zero-point vibrations. (3) Results: Peculiarities of the method are analyzed for reaction with isotopes of Carbon. The developed method takes into account continuity and conservation of quantum flux (describing pycnonuclear reaction) inside the full spacial region of reaction including nuclear region. This gives appearance of new states (called as quasibound states), in which compound nuclear systems of Magnesium are formed with the largest probability. These states have not been studied yet in synthesis of elements in stars. Energy spectra of zero-point vibrations and spectra of quasibound states are estimated with high precision for reactions with isotopes of Carbon. At the first time influence of plasma screening on quasibound states and states of zero-point vibrations in pycnonuclear reactions has been studied. (4) Conclusion: The probability of formation of compound nuclear system in quasibound states in pycnonuclear reaction is essentially larger than the probability of formation of this system in states of zero-point vibrations studied by Zel'dovich and followers. So, synthesis of Magnesium from isotopes of Carbon is more probable through the quasibound states than through the states of zero-point vibrations in compact stars. Energy spectra of zero-point vibrations are changed essentially after taking plasma screening into account. Analysis shows that from all studied isotopes of Magnesium only \isotope[24]{Mg} is stable after synthesis at energy of relative motion of 4.881~MeV of incident nuclei \isotope[12]{C}.
nucl-thastro-ph.SRhep-phUniverse(2023)·5 citations
09
Energy and Angle Dependence of Neutrino Scattering Rates in Proto-Neutron Star and Supernova Matter within Skyrme RPA
Mingya Duan🇫🇷 · Michael Urban🇫🇷
Supernova explosions are the most powerful neutrino sources. The neutrino emission is also the dominating cooling mechanism for a proto-neutron star, whose interior is mainly composed of extremely dense and hot nuclear matter. Neutrino transport is an essential part of the simulation of these phenomena, and modern codes are able to implement inelastic neutrino scattering and also to some extent its angle distribution. We therefore study the energy and angle dependence of neutrino scattering rates in proto-neutron star and supernova matter with the full Skyrme RPA response functions. We confirm earlier findings obtained in the Landau approximation that the RPA reduces neutrino scattering, but the detailed differential scattering rates in hot and dense matter depend sensitively on the adopted interaction. The scattering angle distribution is different for different interactions because it depends strongly on the neutron Fermi velocity. We also find that many Skyrme interactions present an unphysical feature that the Fermi velocity of neutrons exceeds the speed of light already at relatively low densities.
nucl-thPRC(2023)·12 citations
10
Chiral perturbation theory of the hyperfine splitting in (muonic) hydrogen
Franziska Hagelstein🇩🇪 · Vadim Lensky🇩🇪 · Vladimir Pascalutsa🇩🇪
The ongoing experimental efforts to measure the hyperfine transition in muonic hydrogen prompt an accurate evaluation of the proton-structure effects. At the leading order in $α$ , which is $O (α^{5})$ in the hyperfine splitting (hfs), these effects are usually evaluated in a data-driven fashion, using the empirical information on the proton electromagnetic form factors and spin structure functions. Here we perform a first calculation based on the baryon chiral perturbation theory (B $χ$ PT). At leading orders it provides a prediction for the proton polarizability effects in hydrogen (H) and muonic hydrogen ( $μ$ H). We find large cancellations among the various contributions leading to, within the uncertainties, a zero polarizability effect at leading order in the B $χ$ PT expansion. This result is in significant disagreement with the current data-driven evaluations. The small polarizability effect implies a smaller Zemach radius $R_{Z}$ , if one uses the well-known experimental $1 S$ hfs in H or the $2 S$ hfs in $μ$ H. We, respectively, obtain $R_{Z} (H) = 1.010 (9)$ fm, $R_{Z} (μ H) = 1.040 (33)$ fm. The total proton-structure effect to the hfs at $O (α^{5})$ is then consistent with previous evaluations; the discrepancy in the polarizability is compensated by the smaller Zemach radius. Our recommended value for the $1 S$ hfs in $μ H$ is $182.640 (18) meV .$
nucl-thhep-phphysics.atom-phEPJC(2023)·14 citations
11
Is infrared-collinear safe information all you need for jet classification?
Dimitrios Athanasakos🇺🇸 · Andrew J. Larkoski🇺🇸 · James Mulligan🇺🇸 · Mateusz Ploskon🇺🇸 · Felix Ringer🇺🇸
Machine learning-based jet classifiers are able to achieve impressive tagging performance in a variety of applications in high-energy and nuclear physics. However, it remains unclear in many cases which aspects of jets give rise to this discriminating power, and whether jet observables that are tractable in perturbative QCD such as those obeying infrared-collinear (IRC) safety serve as sufficient inputs. In this article, we introduce a new classifier, Jet Flow Networks (JFNs), in an effort to address the question of whether IRC unsafe information provides additional discriminating power in jet classification. JFNs are permutation-invariant neural networks (deep sets) that take as input the kinematic information of reconstructed subjets. The subjet radius and a cut on the subjet's transverse momenta serve as tunable hyperparameters enabling a controllable sensitivity to soft emissions and nonperturbative effects. We demonstrate the performance of JFNs for quark vs. gluon and Z vs. QCD jet tagging. For small subjet radii and transverse momentum cuts, the performance of JFNs is equivalent to the IRC-unsafe Particle Flow Networks (PFNs), demonstrating that infrared-collinear unsafe information is not necessary to achieve strong discrimination for both cases. As the subjet radius is increased, the performance of the JFNs remains essentially unchanged until physical thresholds that we identify are crossed. For relatively large subjet radii, we show that the JFNs may offer an increased model independence with a modest tradeoff in performance compared to classifiers that use the full particle information of the jet. These results shed new light on how machines learn patterns in high-energy physics data
↳ hep-phhep-exnucl-thJHEP(2024)·22 citations
12
Uncertainties on the EFT coupling limits for direct dark matter detection experiments stemming from uncertainties of target properties
Daniel J. Heimsoth🇺🇸 · Brandon Lem🇺🇸 · Anna M. Suliga🇺🇸 · Calvin W. Johnson🇺🇸 · A. Baha Balantekin🇺🇸 · Susan N. Coppersmith🇺🇸
Direct detection experiments are still one of the most promising ways to unravel the nature of dark matter. To fully understand how well these experiments constrain the dark matter interactions with the Standard Model particles, all the uncertainties affecting the calculations must be known. It is especially critical now because direct detection experiments recently moved from placing limits only on the two elementary spin independent and spin dependent operators to the complete set of possible operators coupling dark matter and nuclei in nonrelativistic theory. In our work, we estimate the effect of nuclear configuration-interaction uncertainties on the exclusion bounds for one of the existing xenon-based experiments for all fifteen operators. We find that for operator number 13 the $\pm 1 σ$ uncertainty on the coupling between the dark matter and nucleon can reach more than 50% for dark matter masses between 10 and 1000 GeV. In addition, we discuss how quantum computers can help to reduce this uncertainty and how the uncertainties are affected for couplings obtained for the nonrelativistic reductions of the relativistic interactions.
↳ hep-phastro-ph.COhep-exnucl-thPRD(2023)·6 citations
13
Chiral and trace anomalies in Deeply Virtual Compton Scattering II: QCD factorization and beyond
Shohini Bhattacharya🇺🇸 · Yoshitaka Hatta🇺🇸 · Werner Vogelsang🇩🇪
We extend the discussion of the recently discovered 'anomaly poles' in QCD Compton scattering. We perform the complete one-loop calculation of the Compton amplitude using momentum transfer $t$ as the regulator of collinear divergences. In the gluon channel, we confirm the presence of poles $1/ t$ in both the real and imaginary parts of the amplitude. In the quark channel, we find unexpected infrared single $1/ ϵ$ and double $1/ ϵ^{2}$ poles. We then perform the one-loop calculation of the leading-twist quark generalized parton distributions (GPDs) for quark and gluon external states with the same regulators and find that all these singular terms can be systematically absorbed into the GPDs, showing that QCD factorization is restored to this order. Having established this, we discuss the fate of the $1/ t$ poles. We argue that they become the nonperturbative building blocks of GPDs that encode the chiral and trace anomalies of QCD, in a way consistent with the known constraints these anomalies impose on the nucleon axial and gravitational form factors. The scope of research on GPDs can therefore be expanded to address the manifestation and implications of quantum anomalies in high-energy exclusive processes.
↳ hep-phhep-thnucl-thPRD(2023)·33 citations
14
Absence of inhomogeneous chiral phases in 2+1-dimensional four-fermion and Yukawa models
Laurin Pannullo🇩🇪 · Marc Winstel🇩🇪
We show the absence of an instability of homogeneous (chiral) condensates against spatially inhomogeneous perturbations for various 2+1-dimensional four-fermion and Yukawa models. All models are studied at non-zero baryon chemical potential, while some of them are also subjected to chiral and isospin chemical potential. The considered theories contain up to 16 Lorentz-(pseudo)scalar fermionic interaction channels. We prove the stability of homogeneous condensates by analyzing the bosonic two-point function, which can be expressed in a purely analytical form at zero temperature. Our analysis is presented in a general manner for all of the different discussed models. We argue that the absence of an inhomogeneous chiral phase (where the chiral condensate is spatially non-uniform) follows from this lack of instability. Furthermore, the existence of a moat regime, where the bosonic wave function renormalization is negative, in these models is ruled out.
↳ hep-phcond-mat.str-elnucl-thPRD(2023)·24 citations
15
Ultrastable optical, XUV and soft-x-ray clock transitions in open-shell highly charged ions
Chunhai Lyu · Christoph H. Keitel · Zoltán Harman
Highly charged ions (HCIs) are insensitive to external perturbations and are attractive for the development of ultrastable clocks. However, only a few HCI candidates are known to provide optical clock transitions. In this Letter, we show that, as a result of strong relativistic effects, there are more than 100 suitable optical HCI clock candidates in more than 70 elements. Their transitions are embedded in the fine-structure splitting of the $n d^{4}$ , $n d^{5}$ and $n d^{6}$ ground-state configurations with $n = 3, 4, 5$ being the principal quantum numbers. The corresponding high multipolarity transitions in these ions have lifetimes and quality factors many orders of magnitude longer and larger, respectively, than those in state-of-the-art clocks. Their polarizabilities are also orders of magnitude smaller, rendering them more stable against external electromagnetic fields. Furthermore, within the same electronic configurations, the clock transitions in heavy ions scale up to the XUV and soft-x-ray region, thus enable the development of clocks based on shorter wavelengths. The existence of multiple clock transitions in different charge states of a single element, as well as in a whole isoelectronic sequence, would significantly enrich the detection of fine-structure constant variations, the search for new physics and the test of nuclear theories via high-precision spectroscopy.
↳ physics.atom-phnucl-exnucl-thphysics.opticsCommun.Phys.(2025)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE