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We consider a new approach to the nucleon-nucleon scattering problem in the framework of the higher-derivative formulation of baryon chiral perturbation theory. Starting with a Lorentz-invariant form of the effective Lagrangian we work out…

Nuclear Theory · Physics 2008-11-26 D. Djukanovic , J. Gegelia , S. Scherer , M. R. Schindler

We calculate neutrino processes involving two nucleons at subnuclear densities using chiral effective field theory. Shorter-range noncentral forces reduce the neutrino rates significantly compared with the one-pion exchange approximation…

Nuclear Theory · Physics 2009-11-06 S. Bacca , K. Hally , C. J. Pethick , A. Schwenk

We apply the perturbative chiral quark model to the study of the low-energy pi-N interaction. Using an effective chiral Lagrangian we reproduce the Weinberg-Tomozawa result for the S-wave pi-N scattering lengths. After inclusion of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 V. E. Lyubovitskij , Th. Gutsche , Amand Faessler , R. Vinh Mau

I discuss low-energy pion-nucleon scattering in the framework of chiral perturbation theory. I argue that using this theoretical method one is able to handle the in some cases tremendous experimental accuracy (for the low partial waves). I…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ulf-G. Meißner

An effective field theory is used to give a model-independent description of Compton scattering at energies comparable to the pion mass. The amplitudes for scattering on the proton and the deuteron, calculated to fourth order in small…

Nuclear Theory · Physics 2008-11-26 S. R. Beane , M. Malheiro , J. A. McGovern , D. R. Phillips , U. van Kolck

Positivity constraints on the pion-nucleon scattering amplitude are derived in this article with the help of general S-matrix arguments, such as analyticity, crossing symmetry and unitarity, in the upper part of Mandelstam triangle, R.…

High Energy Physics - Phenomenology · Physics 2015-06-18 Juan Jose Sanz-Cillero , De-Liang Yao , Han-Qing Zheng

Effective field theory techniques are used to describe the interaction of heavy hadrons in a model independent way. Predictability is obtained by exploiting the symmetries of QCD. Heavy hadron chiral perturbation theory is reviewed and used…

High Energy Physics - Phenomenology · Physics 2007-05-23 Iain W. Stewart

We discuss the most general form of the electromagnetic vertex of an off-shell pion. The framework of chiral perturbation theory is used to illustrate the representation dependence of the electromagnetic three-point Green's function. For…

Nuclear Theory · Physics 2007-05-23 S. Scherer

We derive a novel chiral power counting scheme for in-medium chiral perturbation theory with explicit nucleonic and pionic degrees of freedom coupled to external sources. It allows for a systematic expansion taking into account local as…

Nuclear Theory · Physics 2009-12-08 J. A. Oller , A. Lacour , U. -G. Meißner

We investigate threshold pion photoproduction in the framework of heavy baryon chiral perturbation theory. We give the expansion of the electric dipole amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon mass, and…

High Energy Physics - Phenomenology · Physics 2009-09-25 V. Bernard , N. Kaiser , Ulf-G. Meißner

The relativistic amplitudes of pion photo- and electroproduction are calculated by dispersion relations at constant t. Several sum rules and low-energy theorems for the threshold amplitudes are investigated within this technique. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 D. Drechsel , B. Pasquini , L. Tiator

Chiral perturbation theory is a much successful effective field theory of quantum chromodynamics at low energies. The effective Lagrangian is constructed systematically order by order in powers of the momentum $p^2$, and until now the…

High Energy Physics - Phenomenology · Physics 2020-06-18 Nils Hermansson-Truedsson

Chiral symmetry serves as a guiding principle in low-energy hadron dynamics. An effective lagrangian, which explicitly breaks chiral symmetry via a small mass term, allows for a systematic method of calculating higher order corrections to…

Nuclear Theory · Physics 2007-05-23 F. Myhrer

We present a relativistic calculation of pion scattering, pion photoproduction and Compton scattering on the nucleon in the energy region of the \Del-resonance (upto 450 MeV photon lab energy), in a unified framework which obeys the…

Nuclear Theory · Physics 2009-10-30 O. Scholten , A. Yu. Korchin , V. Pascalutsa , D. Van Neck

Chiral perturbation theory is the low energy effective theory of the strong interactions for the light pseudoscalar degrees of freedom. This program is based on effective Lagrangian techniques and is an expansion in the powers of the…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Ananthanarayan

We employ the chiral nucleon-nucleon potential derived in ref.[1] to study bound and scattering states in the two-nucleon system. At next-to-leading order, this potential is the sum of renormalized one-pion and two-pion exchange and contact…

Nuclear Theory · Physics 2011-05-05 E. Epelbaum , W. Glöckle , Ulf-G. Meißner

We present an accurate nucleon-nucleon (NN) potential based upon chiral effective Lagrangians. The model includes one- and two-pion exchange contributions up to chiral order three and contact terms (which represent the short range force) up…

Nuclear Theory · Physics 2017-08-23 D. R. Entem , R. Machleidt

We apply the formalism of Chiral Perturbation Theory out of thermal equilibrium to describe explosive production of pions via the parametric resonance mechanism. To lowest order the lagrangian is that of the Nonlinear Sigma Model where the…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. Gomez Nicola

Broken chiral symmetry has become the basis for a unified treatment of hadronic interactions at low energies. After reviewing mechanisms for spontaneous chiral symmetry breaking, I outline the construction of the low--energy effective field…

High Energy Physics - Phenomenology · Physics 2009-10-31 Gerhard Ecker

An effective hadronic lagrangian consistent with the symmetries of quantum chromodynamics and intended for applications to finite-density systems is constructed. The degrees of freedom are (valence) nucleons, pions, and the low-lying…

Nuclear Theory · Physics 2009-10-30 R. J. Furnstahl , Brian D. Serot , Hua-Bin Tang