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Related papers: Chiral $2\pi$-exchange NN-potentials: Two-loop con…

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A microscopic model for the $N\bar N\to\pi\pi$ process is presented in the meson exchange framework, which in the pseudophysical region agrees with available quasiempirical information. The scalar ($\sigma$) and vector ($\rho$) piece of…

Nuclear Theory · Physics 2009-09-25 C. Schütz , J. W. Durso , K. Holinde , B. C. Pearce , J. Speth

We calculate two-photon exchange amplitude for the elastic electron-pion scattering in the dispersion-relation inspired approach, including both elastic and inelastic contributions. The latter was modelled as a sum of \rho and b_1(1235)…

High Energy Physics - Phenomenology · Physics 2015-03-17 Dmitry Borisyuk , Alexander Kobushkin

We calculate the one--loop corrections to the Kroll--Ruderman low--energy theorems for charged pion photoproduction in the framework of heavy baryon chiral perturbation theory. We predict the threshold S--wave multipole $E_{0+}$ to be…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Bernard , N. Kaiser , Ulf-G. Meißner

Single pion production off nucleons is studied in the framework of relativistic baryon chiral perturbation theory at tree level with the inclusion of the terms from the dimension two effective pion-nucleon Lagrangian. The five appearing…

High Energy Physics - Phenomenology · Physics 2009-10-30 V. Bernard , N. Kaiser , Ulf-G. Meißner

Four of the six parameters defining the two-loop \pi\pi scattering amplitude have been determined using Roy dispersion relations. Combining this information with the Standard \chi PT expressions, we obtain the threshold parameters,…

High Energy Physics - Phenomenology · Physics 2016-09-06 L. Girlanda , M. Knecht , B. Moussallam , J. Stern

In this letter we study the high energy behavior of the forward differential cross section for the $^{18}O(\pi^+,\pi^-)^{18}Ne$ double charge exchange reaction. We have evaluated the sequential and the meson exchange current mechanisms. The…

Nuclear Theory · Physics 2011-02-09 L. Alvarez-Ruso , M. J. Vicente-Vacas

This work elaborates on former remarks of ours regarding two sets of predictions for the observables of the charge-exchange reaction $\pi^- p \to \pi^0 n$ at low energy (pion laboratory kinetic energy $T \leq 100$ MeV). The first prediction…

Nuclear Theory · Physics 2020-01-07 Evangelos Matsinos , Günther Rasche

One of the systematic errors in some of the current lattice computations of the HVP contribution to the muon anomalous magnetic moment $g-2$ is that associated with the extrapolation to the physical pion mass. We investigate this…

High Energy Physics - Lattice · Physics 2018-04-18 Maarten Golterman , Kim Maltman , Santiago Peris

The third-order particle-hole ring diagrams are evaluated for a NN-contact interaction of the Skyrme type. The pertinent four-loop coefficients in the energy per particle $\bar E(k_f) \sim k_f^{5+2n}$ are reduced to double-integrals over…

Nuclear Theory · Physics 2017-08-23 N. Kaiser

We study the central part of Lambda N and Lambda Lambda potential by considering the correlated and uncorrelated two-meson exchange besides the omega exchange contribution. The correlated two-meson is evaluated in a chiral unitary approach.…

Nuclear Theory · Physics 2008-11-26 K. Sasaki , E. Oset , M. J. Vicente Vacas

With an effective Lagrangian approach, we give a full analysis on the $NN \to NN\pi\pi$ and $\bar{N}N\to \bar{N}N\pi\pi$ reactions by exploring the roles of various resonances with mass up to 1.72 GeV. We find large contributions from…

Nuclear Theory · Physics 2011-03-02 Xu Cao , Bing-Song Zou , Hu-Shan Xu

We present an exact analytical evaluation of the two-photon exchange (TPE) correction to the elastic lepton-proton differential scattering cross section at low-energies within the framework of heavy-baryon chiral perturbation theory. Our…

High Energy Physics - Phenomenology · Physics 2026-01-22 Rakshanda Goswami , Pulak Talukdar , Bhoomika Das , Udit Raha , Fred Myhrer

We compare the predictions of different variants of chiral effective field theory for the gamma-p elastic scattering differential cross section. We pay particular attention to the role of pion loops, and the impact that a heavy-baryon…

Nuclear Theory · Physics 2012-12-12 Vadim Lensky , Judith A. McGovern , Daniel R. Phillips , Vladimir Pascalutsa

We study the interactions of an elementary pion with a nucleon made of constituent quarks and show that the enforcement of chiral symmetry requires the use of a two-body operator, whose form does not depend on the choice of the pion-quark…

High Energy Physics - Phenomenology · Physics 2008-11-26 C. M. Maekawa , M. R. Robilotta

We estimate the cross section for quasi-elastic double pion exchange in high energy proton-proton collisions. Total and elastic $\pi\pi$ cross sections are calculated in an equivalent pion approximation, with pion-baryon vertices taken from…

High Energy Physics - Phenomenology · Physics 2009-10-28 Alec J. Schramm , Berndt Müller

The forward doubly-virtual Compton scattering (VVCS) off the nucleon contains a wealth of information on nucleon structure, relevant to the calculation of the two-photon-exchange effects in atomic spectroscopy and electron scattering. We…

High Energy Physics - Phenomenology · Physics 2020-07-15 Jose Manuel Alarcón , Franziska Hagelstein , Vadim Lensky , Vladimir Pascalutsa

We extend a recent three-loop calculation of nuclear matter in the systematic framework of chiral perturbation theory to finite temperatures T. The contributions from one- and two-pion exchange diagrams which cause nuclear binding and…

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

The Pauli rearrangement potential given by the second-order diagram is evaluated for a nucleon optical model potential (OMP) with $G$ matrices of the nucleon-nucleon interaction in chiral effective field theory. The results obtained in…

Nuclear Theory · Physics 2018-12-26 M. Kohno

The leading-particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. The mechanism is related to the isospin-uniform…

High Energy Physics - Phenomenology · Physics 2011-04-15 M. Martinis , V. Mikuta-Martinis , J. Črnugelj

We examine the polarized doubly-virtual Compton scattering (VVCS) off the nucleon using chiral perturbation theory ($\chi$PT). The polarized VVCS contains a wealth of information on the spin structure of the nucleon which is relevant to the…

High Energy Physics - Phenomenology · Physics 2021-03-30 Jose Manuel Alarcón , Franziska Hagelstein , Vadim Lensky , Vladimir Pascalutsa
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