Article
Physics, Nuclear
Martin Schafer, Betzalel Bazak
Summary: We conducted a comprehensive theoretical study on low-energy few-nucleon scattering for systems with A=4, utilizing pionless effective field theory at next-to-leading order. We demonstrated that at this level, the theory can accurately predict the low-energy scattering parameters across all channels studied, with comparable results to the best experimental evaluations and existing theoretical calculations. Our findings confirmed the recent observation of the necessity of a four-body force at next-to-leading order, which was found to only appear in a single spin-isospin channel for nuclear systems.
Article
Astronomy & Astrophysics
Vadim Lensky, Franziska Hagelstein, Vladimir Pascalutsa
Summary: This study provides a systematic assessment of the nuclear contributions to the Lamb shift of muonic deuterium, including radiative corrections and higher-order corrections due to the single-nucleon structure. The findings reveal a correlation between the deuteron charge and Friar radii, and improve the theoretical description of the 2 gamma-exchange contribution, enhancing the agreement between theory and experiment.
Article
Astronomy & Astrophysics
Mirko Bagnarol, Martin Schafer, Betzalel Bazak, Nir Barnea
Summary: In this paper, we present the first calculations of s-wave n-He-4 scattering using pi/EFT framework. Our results, which are in good agreement with experimental data, show the effectiveness of this approach. Furthermore, we estimate the theoretical errors that contribute to our final results.
Article
Physics, Nuclear
Vadim Lensky, Astrid Hiller Blin, Vladimir Pascalutsa
Summary: The study calculates the forward unpolarized doubly-virtual Compton scattering off the deuteron within the framework of pionless effective field theory, providing important insights for future experiments related to the extracted physical quantities. The results of the study also offer a high-precision model-independent input for the calculation of the two-photon-exchange correction to the Lamb shift of muonic deuterium.
Article
Astronomy & Astrophysics
Xiangkai Sun, William Detmold, Di Luo, Phiala E. Shanahan
Summary: Finite-volume pionless effective field theory provides an efficient framework for extrapolating nuclear spectra and matrix elements from finite volume to infinite volume, as well as for extending calculations to larger atomic systems. In this work, the authors demonstrate the implementation of this framework using optimized correlated Gaussian wave functions and solving a generalized eigenvalue problem, which is shown to be significantly more efficient compared to previous stochastic methods.
Article
Physics, Nuclear
Vadim Lensky, Franziska Hagelstein, Vladimir Pascalutsa
Summary: We present a study of the two-photon-exchange corrections to the S-levels in muonic and ordinary deuterium. The calculation is done within the pionless effective field theory and proceeds up to next-to-next-to-next-to-leading order in the expansion. Our findings suggest a larger elastic 2 γ-exchange contribution in muonic deuterium compared to other recent calculations. We also identify a correlation between the deuteron charge and Friar radii, which helps to assess the accuracy of a form factor parametrization. Higher-order 2 γ-exchange contributions are evaluated and their uncertainty is quantified using a Bayesian approach. The extracted deuteron charge radius from different observables is found to be in perfect agreement when taking into account the respective 2 γ-exchange effects.
EUROPEAN PHYSICAL JOURNAL A
(2022)
Article
Physics, Nuclear
S. Dietz, H-W Hammer, S. Konig, A. Schwenk
Summary: Resonances in three-body systems are investigated using pionless effective field theory at leading order. Two complementary methods are employed, including analytically continuing the Faddeev equation to the unphysical sheet and exploring the level structure of three-body states in a finite volume approach. The study focuses on both the three-boson system and the three-neutron system, finding trajectory of Borromean three-body Efimov states turning into resonances for the former and no sign of three-body resonances or virtual states at leading order for the latter.
Article
Physics, Nuclear
M. Ebert, H-W Hammer, A. Rusetsky
Summary: We discuss an alternative scheme for effective range corrections in pionless effective field theory, which shows good convergence for several model potentials.
EUROPEAN PHYSICAL JOURNAL A
(2021)
Article
Astronomy & Astrophysics
W. Detmold, P. E. Shanahan
Summary: The study investigates the use of pionless effective field theory in a finite volume (FVEFT pi/) as a framework to analyze multinucleon spectra and matrix elements calculated in lattice QCD (LQCD). By combining FVEFT pi/ with the stochastic variational method, spectra of nuclei with atomic number A is an element of {2, 3} are matched to existing finite-volume LQCD calculations at heavier-than-physical quark masses, enabling determination of infinite-volume binding energies.
Article
Physics, Nuclear
Thomas R. Richardson, Xincheng Lin, Son T. Nguyen
Summary: Recent proposals for the use of light nuclei as dark-matter direct detection targets require a strong theoretical understanding of nuclear physics. Calculations for dark-matter-light-nucleus scattering are performed using pionless effective field theory and large-N-c expansion. Constraints for the relative sizes of dark-matter couplings to different nucleon currents are obtained through the large-N-c expansion, and used to predict the relative sizes of spin-dependent and spin-independent cross sections for dark-matter scattering off various light nuclei.
Article
Physics, Nuclear
Zichao Yang, Emanuele Mereghetti, Lucas Platter, Matthias R. Schindler, Jared Vanasse
Summary: The electric dipole moments (EDMs) of three-nucleon systems are calculated in pionless effective field theory. Both one-body contributions from permanent proton and neutron EDMs and two-body contributions from charge-parity-odd nucleon-nucleon interactions are considered. The momentum dependence of the electric dipole form factor in the Wigner limit is found to be similar to the charge form factor, indicating proper renormalization.
Article
Astronomy & Astrophysics
D. Djukanovic, T. Harris, G. von Hippel, P. M. Junnarkar, H. B. Meyer, D. Mohler, K. Ottnad, T. Schulz, J. Wilhelm, H. Wittig
Summary: In this study, the isovector electromagnetic form factors of the nucleon were computed using lattice simulations, showing agreement with experimental values and employing various methods to remove bias from excited-state contributions. The estimates for the nucleon magnetic moment and square radius are consistent with experimental measurements.
Article
Physics, Multidisciplinary
G. J. Rampho
Summary: This paper presents the Lagrange-mesh method solution for solving the Noyes-Fiedeldey form of the Faddeev equations in polar coordinates. The spectral representation of the projection kernel is utilized, and generalized Lagrange-mesh matrix elements for the parameterized kinetic energy operator are introduced. The accuracy of the solution is tested by calculating ground state energies and root-mean-square radii of selected three-boson systems, showing rapid convergence for soft-core potentials and slower convergence for singular potentials.
Article
Physics, Multidisciplinary
Ghanashyam Meher, Udit Raha
Summary: In this study, low-energy effective field theory is used to investigate the Xi(-) nn three-body system, revealing a substantial degree of ambiguity due to lack of empirical information and the potential importance of this sector in astrophysical studies. The analysis suggests the existence of Efimov states in the unitary limit and highlights the sensitivity of three-body binding energy to the cutoff parameter, providing insights into the system's behavior and potential applications in hypernuclear physics.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2021)
Article
Physics, Nuclear
A. M. Gasparyan, E. Epelbaum
Summary: We extend the renormalizability study of chiral effective field theory with a finite cutoff to nucleon-nucleon scattering, considering nonperturbative effects. The nucleon-nucleon interaction is expanded up to next-to-leading order, with the leading-order interaction treated nonperturbatively. New features related to the renormalization of the effective field theory are revealed, including more stringent constraints on the leading-order potential to ensure renormalizability and correct power counting for the next-to-leading-order amplitude. Numerical analysis of several partial waves in nucleon-nucleon scattering, 3P0, 3S1-3D1, and 1S0, is conducted to illustrate the theoretical findings, discussing cutoff dependence and convergence of the chiral expansion for these channels.
