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We derive the long-range components of the nucleon-nucleon (NN) two-pion-exchange potential with an intermediate Roper resonance. Leading-order interactions in heavy-baryon chiral perturbation theory are considered. NN phase shifts with…

Nuclear Theory · Physics 2026-03-02 Yang Xiao , Li-Sheng Geng , U. van Kolck

We report measurements of the $\pi^- p \to \pi^o n$ differential cross sections at six momenta (104-143 MeV/c) and four angles (0-40 deg) by detection of $\gamma$-ray pairs from $\pi^o \to \gamma \gamma$ decays using the TRIUMF RMC…

Nuclear Experiment · Physics 2008-11-26 Y. Jia , T. P. Gorringe , M. D. Hasinoff , M. A. Kovash , M. Ojha , M. M. Pavan , S. Tripathi , P. A. Zolnierczuk

We derive from the subleading contributions to the chiral three-nucleon force (long-range terms, published in Phys.\,Rev.\,C\,77, 064004 (2008)) a density-dependent two-nucleon interaction $V_\text{med}$ in isospin-symmetric, spin-saturated…

Nuclear Theory · Physics 2021-04-09 N. Kaiser , B. Singh

We evaluate, within one-loop chiral perturbation theory, the two-pion exchange diagrams with single and double delta-isobar excitation contributing to elastic NN-scattering. We find that virtual $\Delta$-excitation processes (in the static…

Nuclear Theory · Physics 2010-04-06 N. Kaiser , S. Gerstendoerfer , W. Weise

The method of unitary transformations generates five classes of leading-order reducible chiral four-nucleon interactions which involve pion-exchanges and a spin-spin contact-term. Their first-order contributions to the energy per particle…

Nuclear Theory · Physics 2016-02-17 N. Kaiser , R. Milkus

We analyse the interplay between nucleon-nucleon potentials deduced from chiral perturbation theory and a coarse grained representation of the short distance interactions by delta-shells potentials below a certain cut-off distance. While we…

Nuclear Theory · Physics 2013-01-30 Rodrigo Navarro Perez , J. E. Amaro , E. Ruiz Arriola

We present an analysis of isospin-breaking effects in threshold pion-nucleon scattering due to the light quark mass difference and the dominant virtual photon effects. We discuss the deviation from various relations, which are exact in the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Nadia Fettes , Ulf-G. Meißner , Sven Steininger

We use QCD sum rules for the three point function of a pseudoscalar and two nucleonic currents in order to estimate the charge dependence of the pion nucleon coupling constant $g_{NN\pi}$ coming from isospin violation in the strong…

Nuclear Theory · Physics 2008-11-26 T. Meissner , E. M. Henley

pi-N and pi-pi interactions near threshold are uniquely sensitive to the chiral symmetry breaking part of the strong interaction. The pi-N sigma-term value with its implications for nucleon quark structure and the recent controversy…

High Energy Physics - Phenomenology · Physics 2015-06-25 D. Pocanic , E. Frlez

We discuss charge symmetry and charge independence breaking in an effective field theory approach for few-nucleon systems. We systematically introduce strong isospin-violating and electromagnetic operators in the theory. The charge…

Nuclear Theory · Physics 2009-10-31 E. Epelbaum , Ulf-G. Meißner

We calculate the proton and neutron spin contributions for nuclei using semi-empirical methods, as well as a novel hybrid \emph{ab initio}/semi-empirical method, for interpretation of experimental data. We demonstrate that core-polarisation…

High Energy Physics - Phenomenology · Physics 2015-03-10 Y. V. Stadnik , V. V. Flambaum

We calculate the parity-violating nucleon-nucleon potential in heavy-baryon chiral perturbation theory up to the next-to-next-to-leading order. The one-pion exchange comes in the leading order and the next-to-next-to-leading order consists…

Nuclear Theory · Physics 2008-11-26 C. H. Hyun , S. Ando , B. Desplanques

We present the dominant two- and three-pion-exchange contributions to the nucleon-nucleon interaction at sixth order (next-to-next-to-next-to-next-to-next-to-leading order, N5LO) of chiral perturbation theory. Phase shifts with orbital…

Nuclear Theory · Physics 2015-12-16 D. R. Entem , N. Kaiser , R. Machleidt , Y. Nosyk

Based upon the Bonn meson-exchange-model for the nucleon-nucleon ($NN$) interaction, we calculate the charge-independence breaking (CIB) of the $NN$ interaction due to pion-mass splitting. Besides the one-pion-exchange (OPE), we take into…

Nuclear Theory · Physics 2008-11-26 G. Q. Li , R. Machleidt

We examine the effect of isospin-violating meson-nucleon coupling constants on low-energy pion-nucleon scattering. We compute the couplings in the context of a nonrelativistic quark model. The difference between the up and down constituent…

Nuclear Theory · Physics 2011-02-01 Jorge Piekarewicz

The nucleon spin-orbit interaction is a cornerstone of nuclear structure theory, yet its isospin dependence remains elusive owing to the lack of clean experimental probes. Here we show that the charge-weak form factor difference in…

Nuclear Theory · Physics 2026-02-20 Tong-Gang Yue , Zhen Zhang , Lie-Wen Chen

Spin-isospin transitions in nuclei away from the valley of stability are essential for the description of astrophysically relevant weak interaction processes. While they remain mainly beyond the reach of experiment, theoretical modeling…

Nuclear Theory · Physics 2021-06-16 D. Vale , Y. F. Niu , N. Paar

A detailed comparison is made between the spin-orbit interactions in $\Lambda$ hypernuclei and ordinary nuclei. We argue that there are three major contributions to the spin-orbit interaction: 1) a short-range component involving scalar and…

Nuclear Theory · Physics 2008-11-26 N. Kaiser , W. Weise

We construct a coordinate-space chiral potential, including $\Delta$-isobar intermediate states in its two-pion-exchange component. The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders ($Q^2$ and…

Nuclear Theory · Physics 2015-06-23 M. Piarulli , L. Girlanda , R. Schiavilla , R. Navarro Pérez , J. E. Amaro , E. Ruiz Arriola

We extend a recent calculation of the nuclear energy density functional in the framework of chiral perturbation theory by computing the isovector surface and spin-orbit terms: $(\vec \nabla \rho_p- \vec \nabla \rho_n)^2 G_d(\rho)+ (\vec…

Nuclear Theory · Physics 2014-11-20 N. Kaiser