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We evaluate the two-photon exchange correction to the unpolarized cross section in the elastic muon-proton scattering within dispersion relations. One of the six independent invariant amplitudes requires a subtraction. We fix the…

High Energy Physics - Phenomenology · Physics 2024-10-28 Oleksandr Tomalak , Marc Vanderhaeghen

Nucleon recoil polarization observables in $(e,e'\vec{p})$ reactions are investigated using a semi-relativistic distorted-wave model which includes one- and two-body currents with relativistic corrections. Results for the induced…

Nuclear Theory · Physics 2008-11-26 F. Kazemi Tabatabaei , J. E. Amaro , J. A. Caballero

The ETH model of the pion-nucleon ($\pi N$) interaction contains $t$-channel $\sigma$- and $\rho$-exchange graphs, as well as the $s$- and $u$-channel contributions with the well-established $s$ and $p$ baryon states with masses below $2$…

High Energy Physics - Phenomenology · Physics 2014-05-09 Evangelos Matsinos , Günther Rasche

We construct effective one-loop vertices and propagators in the linear sigma model at finite temperature, satisfying the chiral Ward identities and thus respecting chiral symmetry, treating the pion momentum, pion mass and temperature as…

High Energy Physics - Phenomenology · Physics 2009-10-31 Alejandro Ayala , Sarira Sahu

The degree to which a nucleus can act as a source for coherent pion pairs is investigated for intermediate-energy heavy-ion collisions. Creation through both isovector and isoscalar channels is considered. Two experimental signals are…

Nuclear Theory · Physics 2007-05-23 Scott Pratt , Kevin Haglin

Nonperturbative effective field theory calculations for NN scattering seem to break down at rather low momenta. By examining several toy models, we clarify how effective field theory expansions can in general be used to properly separate…

Nuclear Theory · Physics 2009-10-31 David B. Kaplan , James V. Steele

We examine the effects of pseudoscalar and pseudovector coupling of the pi and eta mesons in one-boson exchange models of the NN interaction using two approaches: time-ordered perturbation theory unitarized with the relativistic…

Nuclear Theory · Physics 2009-11-07 G. Caia , J. W. Durso , Ch. Elster , J. Haidenbauer , A. Sibirtsev , J. Speth

The electromagnetic corrections to the low energy scattering amplitude involving charged pions only are investigated at leading and next-to-leading orders in the two-flavour chiral expansion. As an application, the corresponding variation…

High Energy Physics - Phenomenology · Physics 2009-11-07 M. Knecht , A. Nehme

The Compton scattering on a charged pion is studied using the dispersion relations. Unknown mass, full width and decay width into \gamma \gamma of the sigma meson are found from a fit to the experimental data for the process \gamma+\gamma…

High Energy Physics - Phenomenology · Physics 2007-05-23 L. V. Fil'kov , V. L. Kashevarov

We present technical details of the evaluation of the elastic pi-pi scattering amplitude to two loops in chiral perturbation theory. In particular, we elaborate on the renormalization procedure at the two-loop order and on the evaluation of…

High Energy Physics - Phenomenology · Physics 2009-10-30 J. Bijnens , G. Colangelo , G. Ecker , J. Gasser , M. E. Sainio

After a short review of the recent developments in studies of neutrino-nucleus interactions, the predictions for double-differential and integrated charged current-induced quasielastic cross sections are presented within two different…

Nuclear Theory · Physics 2015-05-30 M. B. Barbaro

We revise the conventional nuclear effects of Fermi motion, binding and pionic effects in deep inelastic lepton scattering using a relativistic formalism for an interacting Fermi sea and the local density approximation to translate results…

Nuclear Theory · Physics 2009-10-28 E. Marco , E. Oset , P. Fernández de Córdoba

An extended pion source, which can be temporarily created by a high energy nuclear collision, will also absorb and distort the outgoing pions. We discuss how this effect alters the interferometric pattern of the two-pion momentum…

Nuclear Theory · Physics 2009-09-25 M. -C. Chu , S. Gardner , T. Matsui , R. Seki

We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The…

Nuclear Theory · Physics 2009-11-10 Armen Sedrakian

The production of pions emitted backward in inelastic neutrino-nucleus interactions is analyzed within the impulse approximation in the framework of the dual parton model. We focus on the $Q^2$-dependence of the multiplicity of negative…

Nuclear Theory · Physics 2009-11-07 O. Benhar , S. Fantoni , G. I. Lykasov , U. Sukhatme

The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful…

High Energy Physics - Phenomenology · Physics 2016-09-14 Earle L. Lomon , Simone Pacetti

We describe a model for pion production off nucleons and coherent pions from nuclei induced by neutrinos in the 1 GeV energy regime. Besides the dominant Delta pole contribution, it takes into account the effect of background terms required…

Nuclear Theory · Physics 2017-08-23 M. Valverde , J. E. Amaro , E. Hernandez , J. Nieves , M. J. Vicente Vacas

The Compton scattering on a charged pion and the process \gamma\gamma \to \pi^0\pi^0 are studied using the dispersion relations. Unknown parameters of the S-wave \pi\pi interaction, represented as a board Breit-Wignar resonance, and a sum…

Nuclear Theory · Physics 2011-07-19 L. V. Fil'kov , V. L. Kashevarov

This is the contribution to the proceedings of the MENU 2010 conference. The recent work of Ref. [7] is summarized. Elastic piN scattering and the reaction pi^+ p --> K^+ Sigma^+ are described simultaneously in a unitary coupled-channels…

Nuclear Theory · Physics 2015-05-20 M. Döring

Single pion production off nucleons is studied in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. Using total and some older differential cross section data to pin down the low-energy…

High Energy Physics - Phenomenology · Physics 2009-10-31 Nadia Fettes , Véronique Bernard , Ulf-G. Meißner