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The final state interactions in $K^\pm\to\pi^\pm\pi^0\pi^0$ decays are considered using the methods of non-relativistic quantum mechanics. We show how to take into account the largest electromagnetic effects in the analysis of experimental…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. R. Gevorkyan , D. T. Madigozhin , A. V. Tarasov , O. O. Voskresenskaya

The extraction of the isovector s-wave pi N amplitude from pionic atoms is studied with special emphasis on uncertainties and their dependence on the assumptions made regarding the neutron density distributions in nuclei and on the size of…

Nuclear Theory · Physics 2009-11-10 E. Friedman , A. Gal

Using newly calculated electromagnetic corrections, we have made a phase shift analysis of experimental data on pi+/- p elastic scattering up to 100 MeV, assuming the effective hadronic interaction to be isospin invariant. The output…

High Energy Physics - Phenomenology · Physics 2007-10-18 A. Gashi , E. Matsinos , G. C. Oades , G. Rasche , W. S. Woolcock

The elastic pi-N scattering amplitude in the isospin limit is calculated in the framework of heavy baryon chiral perturbation theory, up to the third order. Threshold parameters like scattering lengths, volumes, effective ranges, etc. are…

High Energy Physics - Phenomenology · Physics 2011-09-13 Martin Mojzis

In recent years, a persistent tension between phenomenological and lattice QCD determinations of the pion-nucleon $\sigma$-term $\sigma_{\pi N}$ has developed. In particular, lattice-QCD calculations have matured to the point that…

High Energy Physics - Phenomenology · Physics 2023-06-16 Martin Hoferichter , Jacobo Ruiz de Elvira , Bastian Kubis , Ulf-G. Meißner

We review the structure of Roy-Steiner equations for pion-nucleon scattering, the solution for the partial waves of the t-channel process $\pi\pi\to \bar N N$, as well as the high-accuracy extraction of the pion-nucleon S-wave scattering…

High Energy Physics - Phenomenology · Physics 2016-03-24 Martin Hoferichter , Jacobo Ruiz de Elvira , Bastian Kubis , Ulf-G. Meißner

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

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

We present a novel analysis of the $\pi N$ scattering amplitude in Lorentz covariant baryon chiral perturbation theory renormalized in the extended-on-mass-shell scheme. This amplitude, valid up to $\mathcal{O}(p^3)$ in the chiral…

High Energy Physics - Phenomenology · Physics 2015-05-30 J. M. Alarcon , J. Martin Camalich , J. A. Oller

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

This work provides a brief history of determinations of the pion-nucleon ($\pi N$) coupling constant from $\pi N$ and $N N$ data. From robust analyses of twenty reported values of the charged-pion coupling constant, exhibiting sizeable…

Nuclear Theory · Physics 2019-04-18 Evangelos Matsinos

The pion-nucleon scattering is investigated by using several three-dimensional reduction schemes of the Bethe-Salpeter equation for a model Lagrangian involving $\pi$, $N$, $\Delta$, $\rho$, and $\sigma$ fields. It is found that all of the…

Nuclear Theory · Physics 2009-11-07 Cheng-Tsung Hung , Shin Nan Yang , T. -S. H. Lee

Measurements of elastic scattering of 21.5 MeV pi+ and pi- by Si, Ca, Ni and Zr were made using a single arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a…

We give the conversion equations which lead from experimental values of the $3p \to 1s$ transition energy in pionic hydrogen and the total width of the $1s$ level to values of the s-wave threshold scattering parameters for the processes…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. C. Oades , G. Rasche , W. S. Woolcock , E. Matsinos , A. Gashi

We calculate the electromagnetic corrections to the isospin invariant mixing angle and to the two eigenphases for the $s$-, $p_{1/2}$- and $p_{3/2}$-partial waves for $\pi^- p$ elastic and charge exchange scattering. These corrections have…

High Energy Physics - Phenomenology · Physics 2007-10-18 A. Gashi , E. Matsinos , G. C. Oades , G. Rasche , W. S. Woolcock

We calculate the electromagnetic corrections to the isospin invariant mixing angle and to the two eigenphases for the s and p-waves for low energy pi-p elastic and charge exchange scattering. These corrections have to be applied to the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Gashi , E. Matsinos , G. C. Oades , G. Rasche , W. S. Woolcock

The experimental data on pi N scattering in the elastic energy region T_pi < 250 MeV are analyzed within the multichannel K-matrix approach with effective Lagrangians. Isospin invariance is not assumed in this analysis and the physical…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. B. Gridnev , I. Horn , W. J. Briscoe , I. I. Strakovsky

Predictions of the existence of well-defined deeply bound pionic atom states for heavy nuclei and the eventual observation of such states by the (d,3He) reaction have revived interest in the pion-nucleus interaction at threshold and in its…

Nuclear Theory · Physics 2010-10-27 E. Friedman

We complete and improve the fits to experimental $\pi\pi$ scattering amplitudes, both at low and high energies, that we performed in the previous papers of this series. We then verify that the corresponding amplitudes satisfy analyticity…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. Kaminski , J. R. Pelaez , F. J. Yndurain

We present a new phenomenological Nucleon-Nucleon chiral potential fitted to 925 pp and 1743 np scattering data selected from the Granada-2013 NN-database up to a laboratory energy of $125$ MeV with 20 short distance parameters and three…

Nuclear Theory · Physics 2015-05-13 R. Navarro Perez , J. E. Amaro , E. Ruiz Arriola