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We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz…

High Energy Physics - Phenomenology · Physics 2016-05-25 De-Liang Yao , D. Siemens , V. Bernard , E. Epelbaum , A. M. Gasparyan , J. Gegelia , H. Krebs , Ulf-G. Meißner

We study meson-baryon scattering with strangeness -1 in unitary chiral perturbation theory. Ten coupled channels are considered in our work, namely $\pi^0 \Lambda$, $\pi^0 \Sigma^0$, $\pi^- \Sigma^+$, $\pi^+ \Sigma^-$, $K^- p$, $\bar{K}^0…

High Energy Physics - Phenomenology · Physics 2013-11-15 Zhi-Hui Guo , J. A. Oller

We apply the effective field theory approach to the three-nucleon system. In particular, we consider neutron-deuteron scattering and the triton. Precise predictions for S=3/2 scattering are obtained in a straightforward way. In the S=1/2…

Nuclear Theory · Physics 2007-05-23 H. -W. Hammer

The low energy scattering of pions is investigated in the presence of electromagnetic interactions at leading order and at next-to-leading order for the amplitudes involving at most one pair of charged pions. The size of the electromagnetic…

High Energy Physics - Phenomenology · Physics 2011-05-05 Marc Knecht , Res Urech

We extend the pion-nucleus multiple-scattering framework to include detailed second-order rescattering dynamics for nuclei with non-zero isospin. To account for intermediate charge-exchange and nucleon spin-flip effects, we develop a…

This article reviews unitarization methods essential for extending Effective Field Theories (EFTs) beyond their perturbative limits, particularly in hadronic and electroweak (EW) sectors. Perturbative EFTs, like Chiral Perturbation Theory…

High Energy Physics - Phenomenology · Physics 2026-03-04 Alexandre Salas-Bernárdez

This paper presents the fascinating correspondence between the geometric function theory and the scattering amplitudes with $O(N)$ global symmetry. A crucial ingredient to show such correspondence is a fully crossing symmetric dispersion…

High Energy Physics - Theory · Physics 2021-12-13 Ahmadullah Zahed

We use the framework of effective field theories to discuss the determination of the S-wave \pi N scattering lengths from the recent high-precision measurements of pionic deuterium observables. The theoretical analysis proceeds in several…

Nuclear Theory · Physics 2014-11-18 Ulf-G. Meißner , Udit Raha , Akaki Rusetsky

The measurement of the pion-nucleon scattering lengths constitutes a high-precision test of the methods of Chiral Pertubation Theory, which is the low-energy approach of QCD. The pion-nucleon s-wave scattering lengths are related to the…

High Energy Physics - Experiment · Physics 2007-05-23 D. Gotta

We investigate the parity-violating analyzing power in neutron capture on the proton at thermal energies in the framework of chiral effective field theory. By combining this analysis with a previous analysis of parity violation in…

Nuclear Theory · Physics 2015-06-15 J. de Vries , N. Li , Ulf-G. Meißner , A. Nogga , E. Epelbaum , N. Kaiser

Recent proposals for the use of light nuclei as dark matter direct detection targets necessitate a strong theoretical understanding of the nuclear physics involved. We perform relevant calculations for dark matter-light nucleus scattering…

Nuclear Theory · Physics 2022-10-27 Thomas R. Richardson , Xincheng Lin , Son T. Nguyen

A number of recent references have pointed out that an N-particle system having short-range interactions at S-wave and/or P-wave unitarity can exhibit modified threshold behavior for various reactive processes. But the question of how close…

High Energy Physics - Phenomenology · Physics 2025-09-10 Michael D. Higgins , J. Golak , R. Skibinski , K. Topolnicki , H. Witala , H. Kamada , Chris H. Greene

The renormalisation of NN scattering in theories with zero-range interactions is examined using a cut-off regularisation and taking the cut-off to infinity. Inclusion of contact interactions that depend on energy as well as momentum allows…

High Energy Physics - Phenomenology · Physics 2007-05-23 Keith G. Richardson , Michael C. Birse , Judith A. McGovern

Many of the quantities of interest at the precision frontier in particle physics require a good understanding of the strong interaction at low energies. The present talk reviews the theoretical framework used in this context. In particular,…

High Energy Physics - Phenomenology · Physics 2015-11-04 H. Leutwyler

Chiral perturbation theory is the effective field theory of the standard model. In this talk, I discuss some applications of this framework to the pion--nucleon system. These are chiral corrections to the S--wave pion--nucleon scattering…

High Energy Physics - Phenomenology · Physics 2011-04-15 Ulf-G. Meißner

Dark pion is a promising candidate for the strongly interacting massive particle dark matter. A large pion self-coupling $m_\pi/f_\pi$ tends to be required for correct relic abundance, and hence the partial-wave amplitudes can violate the…

High Energy Physics - Phenomenology · Physics 2023-03-06 Ayuki Kamada , Shin Kobayashi , Takumi Kuwahara

We report on the recent developments of a new effective field theory for nuclear matter [1,2,3]. We present first the nuclear matter chiral power counting that takes into account both short-- and long--range inter-nucleon interactions. It…

Nuclear Theory · Physics 2011-01-04 A. Lacour , U. -G. Meissner , J. A. Oller

We discuss a role of dibaryon fields in an effective field theory to study pion cloud effect around the unitary limit of two nucleon systems at low energies.

Nuclear Theory · Physics 2015-07-21 Shung-Ichi Ando

The energy spectrum of two short-range interacting particles in a harmonic potential trap has previously been related to free-space scattering phase shifts. But the existing formula for this purpose is exact only in the limit of an…

Nuclear Theory · Physics 2020-05-20 Xilin Zhang

This report presents an investigation of the pion-nucleon elastic scattering in low energy region using a production representation of the partial wave $S$ matrix. The phase shifts are separated into contributions from poles and branch…

High Energy Physics - Phenomenology · Physics 2019-02-20 Yu-Fei Wang