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Chiral effective field theory predicts a specific charge symmetry violating amplitude for pion production. This term is shown to provide the dominant contribution to the forward-backward asymmetry in the angular distribution for the…

Nuclear Theory · Physics 2011-02-01 U. van Kolck , J. A. Niskanen , G. A. Miller

The scalar-isoscalar term in the two-pion exchange $NN$ potential is abnormally large and does not respect the hierarchy of effects predicted by chiral perturbation theory. We argue that this anomaly is associated with non-perturbative…

Nuclear Theory · Physics 2009-01-16 M. R. Robilotta , G. R. S. Zarnauskas

We calculate the pion self-energies in asymmetric nuclear matter in the two-loop approximation of chiral perturbation theory. We find three types of corrections beyond the well-known linear density approximation. The resulting s-wave…

Nuclear Theory · Physics 2009-11-07 N. Kaiser , W. Weise

We present a nucleon-nucleon potential at fifth order in chiral effective field theory. We find a substantial improvement in the description of nucleon-nucleon phase shifts as compared to the fourth-order results of Ref. [E. Epelbaum, H.…

Nuclear Theory · Physics 2015-09-23 E. Epelbaum , H. Krebs , U. -G. Meißner

Effects of three-nucleon forces arising from the exchange of a pion and a scalar-isoscalar object among three nucleons on nucleon-deuteron scattering observables are studied.

Nuclear Theory · Physics 2008-11-26 S. Ishikawa

We study the leading isospin-breaking contributions to the two-nucleon two-pion exchange potential due to explicit Delta degrees of freedom in chiral effective field theory. In particular, we find important contributions due to the delta…

Nuclear Theory · Physics 2009-07-29 E. Epelbaum , H. Krebs , Ulf-G. Meißner

The pion multiplicity per participating nucleon in central nucleus-nucleus collisions at the energies 2-15 A GeV is significantly smaller than in nucleon-nucleon interactions at the same collision energy. This effect of pion suppression is…

Nuclear Theory · Physics 2011-09-13 Marek Gazdzicki , Mark I. Gorenstein , Stanislaw Mrowczynski

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

Partial restoration in nuclear matter of the chiral symmetry of QCD is discussed together with some of its possible signals. Estimates of corrections to the leading, linear dependence of the quark condensate are found to be small, implying…

Nuclear Theory · Physics 2009-10-28 Michael C. Birse

We consider a new three-nucleon force generated by the exchange of one pion in the presence of a 2N correlation. The underlying irreducible diagram has been recently suggested by the authors as a possible candidate to explain the puzzle of…

Nuclear Theory · Physics 2009-11-06 L. Canton , W. Schadow

We derive the equation of state of symmetric nuclear matter in a relativistic theory with $\sigma$ and $\omega$ exchange. We take a chiral version of this model which insures all the chiral constraints. Going beyond the mean field approach…

Nuclear Theory · Physics 2008-11-26 G. Chanfray , M. Ericson

The nucleon-pion-state contributions to QCD 2- and 3-point functions used in the calculation of the nucleon axial charge are studied in chiral perturbation theory. For sufficiently small quark masses and large volumes the nucleon-pion…

High Energy Physics - Lattice · Physics 2015-08-06 Oliver Bar

We examine the role of the elementary isoscalar pion--nucleon scattering amplitude in the description of the processes $pp \to pp\pi^0$ and $pp\to d\pi^+$ at threshold. We argue that the presently used tree level dimension two approximation…

Nuclear Theory · Physics 2009-10-30 C. Hanhart , J. Haidenbauer , M. Hoffmann , Ulf-G. Meißner , J. Speth

In-medium chiral perturbation theory is used to calculate the density dependence of the quark condensate $<\bar qq>$. The corrections beyond the linear density approximation are obtained by differentiating the interaction contributions to…

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

Leading-order three-nucleon forces that violate isospin symmetry are calculated in Chiral Perturbation Theory. The effect of the charge-symmetry-breaking three-nucleon force is investigated in the trinucleon systems using Faddeev…

Nuclear Theory · Physics 2014-11-18 J. L. Friar , G. L. Payne , U. van Kolck

The work that Peter Schuck and I carried out during the nineties in collaboration with the Lyon and Darmstadt theory groups is summarized. I retrace how our theoretical developments combined with experimental results concerning the…

Nuclear Theory · Physics 2023-10-31 Guy Chanfray

Chiral perturbation theory supplemented by the Omnes function is employed to study the strength of the isoscalar central nuclear interaction, G_S, in the chiral limit vs the physical case. A very large modification is seen, i.e. eta_s = G_S…

Nuclear Theory · Physics 2011-07-19 John F. Donoghue

We take an approach to the Lambda non-mesonic weak decay in nuclei based on the exchange of mesons. The one pion and one kaon exchange are considered, together with the exchange of two pions, either correlated, leading to an important…

Nuclear Theory · Physics 2009-11-07 D. Jido , E. Oset , J. E. Palomar

We consider two methods to find the effective parameters of the pion traversing a nuclear medium. One is the first order chiral perturbation theoretic evaluation of the pion pole contribution to the two-point function of the axial-vector…

Nuclear Theory · Physics 2009-11-10 S. Mallik , Sourav Sarkar

We present realistic models of pion-exchange three-nucleon interactions obtained by fitting the energies of all the 17 bound or narrow states of 3 <= A <= 8 nucleons, calculated with less than 2% error using the Green's function Monte Carlo…

Nuclear Theory · Physics 2008-11-26 Steven C. Pieper , V. R. Pandharipande , R. B. Wiringa , J. Carlson
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