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We investigate the role of the delta isobar in the reaction $\pi d\to \pi d$ at threshold in chiral effective field theory. We discuss the corresponding power counting and argue that this calculation completes the evaluation of diagrams up…

Nuclear Theory · Physics 2008-11-26 V. Baru , J. Haidenbauer , C. Hanhart , A. Kudryavtsev , V. Lensky , U. -G. Meißner

Roles of the $\Delta (1232)$, ${N}^{*}(1520)$, and ${N}^{*}(1650)$ resonances in the $\gamma p\to{\pi }^{0}{\pi }^{0}p $ reaction near threshold is investigated within an effective Lagrangian approach. We have calculated the differential…

High Energy Physics - Phenomenology · Physics 2025-01-28 Meng-Yuan Dai , Si-Wei Liu , Cheng Chen , De-Min Li , En Wang , Ju-Jun Xie

The renormalization of the chiral np interaction with Delta-excitations in intermediate states is considered at next-to-leading order (NLO) and next-to-next-to-leading order (N2LO) for central waves. The inclusion of the Delta-excitation as…

Nuclear Theory · Physics 2009-12-31 M. Pavon Valderrama , E. Ruiz Arriola

We study an effective field theory of interacting nucleons at distances much greater than the pion's Compton wavelength. In this regime the NN potential is conjectured to be the sum of a delta function and its derivatives. The question we…

Nuclear Theory · Physics 2009-04-17 S. R. Beane , T. D. Cohen , D. R. Phillips

Charged-current single pion production in scattering off 12C is investigated for neutrino energies up to 1 GeV. An impact of nuclear effects with in-medium modifications of the Delta(1232) resonance properties as well as an effective field…

Nuclear Theory · Physics 2016-11-28 Jan T. Sobczyk. , Jakub Żmuda

In this paper we implement for the first time the use of a {\pi}N{\Delta}(1232) vertex interaction containing both first and second order derivative terms, as required by renormalization considerations. As as was previously shown both…

High Energy Physics - Phenomenology · Physics 2019-08-07 Alejandro Mariano , Daniel Badagnani , Cesar Barbero

We reinvestigate the experimental data on $\omega$--meson production in pion-nucleon collisions based on both an analytical approach and a Monte Carlo simulation. Our analysis allows us to study the kinematical peculiarities of the…

High Energy Physics - Phenomenology · Physics 2007-05-23 C. Hanhart , A. Sibirtsev , J. Speth

The $\pi$, $\eta$ and $\rho$ exchange contributions to the cross-section for the reaction $pp\to pp\eta$ near threshold are calculated with a phenomenological description of the intermediate S11 (N(1535)) resonance for all exchange…

Nuclear Theory · Physics 2016-08-15 M. T. Peña , H. Garcilazo , D. O. Riska

The total cross section of the $pp\to pp\pi^0$ reaction near threshold is calculated in pionless effective field theory with a di-baryon and external pions. The amplitudes for a leading one-body and subleading contact neutral pion…

Nuclear Theory · Physics 2008-11-26 Shung-ichi Ando

We have extended a model for the $\gamma N\to \pi\pi N$ reaction to virtual photons and selected the diagrams which have a $\Delta$ in the final state. With this model we have evaluated cross sections for the virtual photon cross section as…

Nuclear Theory · Physics 2009-10-31 J. C. Nacher , E. Oset

We present a fully relativistic formalism for describing neutrino-induced $\Delta$-mediated single-pion production from nuclei. We assess the ambiguities stemming from the $\Delta$ interactions. Variations in the cross sections of over 10%…

Nuclear Theory · Physics 2009-12-31 C. Praet , O. Lalakulich , N. Jachowicz , J. Ryckebusch

We have applied the extended factorization scheme to investigate the electroweak pion production on nuclei. The ANL-Osaka model, which was obtained by analyzing the data of $\pi N$, $\gamma N$, $N(e,e'\pi)$ and $N(\nu,\mu\,\pi) $ reactions…

Nuclear Theory · Physics 2019-10-30 Noemi Rocco , Satoshi X. Nakamura , T. -S. H. Lee , Alessandro Lovato

The charge changing weak production of Delta in nucleons and nuclei is studied. The reactions e^{-} p -> Delta^{0} \nu_{e} and e^{+} p -> Delta^{++} \bar{\nu}_{e} are considered as a possible source of information about the weak N-Delta…

Nuclear Theory · Physics 2011-02-09 L. Alvarez-Ruso , E. Oset , S. K. Singh , M. J. Vicente Vacas

Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the $\Delta(1232)$ resonance is investigated. The calculations include an impulse term and one-loop contributions…

Nuclear Theory · Physics 2015-03-18 Jia-Jun Wu , T. Sato , T. -S. H. Lee

The reaction pi N -> pi pi N is studied at tree level up to next-to-leading order in the framework of manifestly covariant baryon chiral perturbation theory with explicit Delta(1232) degrees of freedom. Using total cross section data to…

Nuclear Theory · Physics 2014-07-09 D. Siemens , V. Bernard , E. Epelbaum , H. Krebs , Ulf-G. Meißner

The neutrino pion production off the nucleon is traditionally described in the literature by means of the weak excitation of the Delta(1232) resonance and its subsequent decay into N pi. Here, we present results from a model that includes…

High Energy Physics - Experiment · Physics 2008-11-26 E. Hernandez , J. Nieves , M. Valverde

It is argued that Weinberg's approach to the nucleon-nucleon (NN) interaction problem within effective field theory provides a consistent power counting for renormalized diagrams. Within this scheme the NN potential is organized as an…

Nuclear Theory · Physics 2009-11-10 J. Gegelia , S. Scherer

From the pion production rates n_{pi} / A_{part} and the pion charge ratios R_{pi} = n_{pi^-} / n_{pi^+} and S_{pi} = n_{pi^0} / (n_{pi^-} + n_{pi^+}), measured in p + A and A + A reactions, it is concluded that the mass of the Delta(1232)…

Nuclear Experiment · Physics 2007-05-23 D. Pelte

The results from an investigation of the incoherent single pion electroweak production on the deuteron in the $\Delta$(1232) region are reported. The importance of including the nucleon-nucleon final state interactions in extracting the…

Nuclear Theory · Physics 2016-12-21 T. -S. H. Lee

We consider the $\Lambda N\to NN$ weak transition, responsible for a large fraction of the non-mesonic weak decay of hypernuclei. We follow on the previously derived effective field theory and compute the next-to-leading one-loop…

Nuclear Theory · Physics 2013-04-30 Axel Pérez-Obiol , David R. Entem , Bruno Juliá-Díaz , Assumpta Parreño