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Related papers: Chiral Dynamics of Deeply Bound Pionic Atoms

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We formulate microscopic neutron-nucleus optical potentials from many-body perturbation theory based on chiral two- and three-body forces. The neutron self energy is first calculated in homogeneous matter to second order in perturbation…

Nuclear Theory · Physics 2020-07-01 T. R. Whitehead , Y. Lim , J. W. Holt

We consider the chiral expansion of the threshold amplitude for the reaction $\gamma p \to \pi^0 \pi^0 p$ to order ${\cal O}(M_\pi^2)$. We substantiate a claim that this photoproduction channel is significantly enhanced close to threshold…

Nuclear Theory · Physics 2009-10-30 V. Bernard , N. Kaiser , Ulf-G. Meißner

Recently we have developed a novel chiral power counting scheme for an effective field theory of nuclear matter with nucleons and pions as degrees of freedom [1]. It allows for a systematic expansion taking into account both local as well…

Nuclear Theory · Physics 2011-02-01 A. Lacour , J. A. Oller , U. -G. Meißner

A meson exchange model of the $\pi\pi$ interaction which fits free $\pi\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions…

Nuclear Theory · Physics 2009-10-30 R. Rapp , J. W. Durso , J. Wambach

We use chiral perturbation theory to investigate hadronic properties in strong electric and magnetic fields. A strong-field power counting is employed, and results for pions and nucleons are obtained using Schwinger's proper-time method. In…

High Energy Physics - Phenomenology · Physics 2008-12-18 Brian C. Tiburzi

Spin-isospin response in exotic nuclear systems is investigated. It is found that in some nuclei excitations with pionic quantum numbers (0-, 1+, 2-, ...) appear at very low energies with large transition probabilities, which is an…

Nuclear Theory · Physics 2015-10-28 Elena Litvinova

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

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

The values of charged pion polarizabilities obtained in the framework of chiral perturbation theory at the level of two-loop accuracy are compared with the experimental result recently reported by COMPASS Collaboration. It is found that the…

High Energy Physics - Phenomenology · Physics 2015-12-09 Mikhail A. Ivanov

A dynamical model for S-- and P--wave correlated $2 \pi$ (and $K \bar K$) exchange between a kaon and a nucleon is presented, starting from corresponding $N \bar N \rightarrow K \bar K$ amplitudes in the pseudophysical region, which have…

Nuclear Theory · Physics 2009-10-28 M. Hoffmann , J. W. Durso , K. Holinde , B. C. Pearce , J. Speth

The low-energy effective theory of nuclear physics based on chiral symmetry is reviewed. Topics discussed include the nucleon-nucleon force, few-body potentials, isospin violation, pion-deuteron scattering, proton-neutron radiative capture,…

High Energy Physics - Phenomenology · Physics 2009-10-30 U. van Kolck

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

A reanalysis of the radiative pion decay together with the calculation of the radiative corrections within chiral perturbation theory (CHPT) is performed. The amplitude of this decay contains an inner Bremsstrahlung contribution and a…

High Energy Physics - Phenomenology · Physics 2008-11-26 Rene Unterdorfer , Hannes Pichl

Chiral extrapolation of the $X(3872)$ binding energy is investigated using the modified Weinberg formulation of chiral effective field theory for the $D \bar{D}^*$ scattering. Given its explicit renormalisability, this approach is…

High Energy Physics - Phenomenology · Physics 2015-12-16 V. Baru , E. Epelbaum , A. A. Filin , J. Gegelia , A. V. Nefediev

We extend a recent three-loop calculation of nuclear matter in chiral perturbation theory by including the effects from two-pion exchange with single and double virtual $\Delta(1232)$-isobar excitation. Regularization dependent short-range…

Nuclear Theory · Physics 2009-11-10 S. Fritsch , N. Kaiser , W. Weise

We study the effects of the $\Delta$(1232) resonance as an effective degree of freedom for charged and neutral pion photo-production on nucleons. Different observables have been calculated for these processes by using relativistic chiral…

High Energy Physics - Phenomenology · Physics 2019-11-27 Gustavo H. Guerrero Navarro

We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the dominant two-pion exchange nucleon-nucleon interaction that is generated by the isoscalar $\pi N$ contact-vertex proportional to the large…

Nuclear Theory · Physics 2008-11-26 N. Kaiser

The scattering amplitude of the pion-nucleon elastic scattering is calculated by the lowest-order approximation of the perturbative expansion with the non-perturbative term. The self-energy of nucleon is determined so as to give the…

Nuclear Theory · Physics 2022-04-22 Susumu Kinpara

We study pion--nucleon scattering with a chiral lagrangian of pions, nucleons, and $\Delta$-isobars to order $Q^3$, where $Q$ is a generic small momentum. We compare the results from heavy baryon chiral perturbation theory with those from…

Nuclear Theory · Physics 2009-11-07 Kenichi Torikoshi , Paul J. Ellis

We calculate electromagnetic neutral pion production off three-nucleon bound states (3H, 3He) at threshold to leading one-loop order in the framework of chiral nuclear effective field theory. In addition, we analyze the dependence of the…

Nuclear Theory · Physics 2011-06-07 Mark Lenkewitz , Evgeny Epelbaum , H. -W. Hammer , Ulf-G. Meißner

We show that processes involving pions that remain very near their mass-shell can be reliably computed in the pionless effective field theory, with the pion integrated in as a heavy field. As an application, we compute the pion-deuteron…

Nuclear Theory · Physics 2009-11-07 Silas R. Beane , Martin J. Savage