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Pion photoproduction is analyzed with the chiral Lagrangian. Partial-wave amplitudes are obtained by an analytic extrapolation of subthreshold reaction amplitudes computed in chiral perturbation theory, where the constraints set by…

High Energy Physics - Phenomenology · Physics 2015-03-17 A. M. Gasparyan , M. F. M. Lutz

We consider the cross section of the deep inelastic pion electroproduction on a proton target at threshold for Q^2 in the region 5-10 GeV^2. The corresponding amplitudes are described in terms of two form factors which we calculate using…

High Energy Physics - Phenomenology · Physics 2008-11-26 V. M. Braun , D. Yu. Ivanov , A. Lenz , A. Peters

Pion electroproduction amplitudes predicted by three theoretical models in the $Q^2 \leq 0.5$ (GeV/c)$^2$ region are compared. The objective is to facilitate the analyses of the data from new experiments on investigating the pion cloud…

Nuclear Theory · Physics 2007-05-23 T. Sato , T. -S. H. Lee

We report on two pion-photoproduction measurements in the threshold region conducted in the A2 collaboration at MAMI with the almost 4{\pi} Crystal Ball detector. The first was with a linearly polarized photon beam and unpolarized…

Nuclear Experiment · Physics 2013-08-13 David Hornidge

Threshold neutral pion photoproduction on the deuteron is studied in the framework of baryon chiral perturbation theory beyond next-to--leading order in the chiral expansion. To fourth order in small momenta, the amplitude is finite and a…

High Energy Physics - Phenomenology · Physics 2009-10-30 S. R. Beane , V. Bernard , T. -S. H. Lee , Ulf-G. Meißner , U. van Kolck

We investigate the pion photoproduction in the \Delta(1232) region in the framework of an effective Lagrangian including pions, nulceon and \Delta(1232). We work to third order in a small scale expansion with both $m_{\pi}$ and…

Nuclear Theory · Physics 2009-10-31 Chung Wen Kao , Thomas D. Cohen

The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it…

High Energy Physics - Phenomenology · Physics 2016-06-22 Astrid Hiller Blin , Manuel Vicente Vacas , Tim Ledwig

We give a brief account of recent theoretical developments in prompt photon production.

High Energy Physics - Phenomenology · Physics 2007-05-23 Eric Laenen , George Sterman , Werner Vogelsang

We study production and equilibration of pions and muons in relativistic electron-positron-photon plasma at a temperature $T\ll m_\mu, m_\pi $. We argue that the observation of pions and muons can be a diagnostic tool in the study of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Inga Kuznetsova , Dietrich Habs , Johann Rafelski

We describe the pion electroproduction processes in the $\Delta$(1232)-resonance region within the framework of chiral effective-field theory. By studying the observables of pion electroproduction in a next-to-leading order calculation we…

High Energy Physics - Phenomenology · Physics 2014-11-18 Vladimir Pascalutsa , Marc Vanderhaeghen

The photoproduction of a neutral pion on the deuteron is considered in the energy region around the eta threshold, where a bump-like structure was observed at very backward pion angles. Different dynamical aspects which may be responsible…

Nuclear Theory · Physics 2009-11-11 A. Fix

The processes of muons (tau) and charged pions pairs production at electron-positron annihilation with first order radiative corrections are considered. The calculation results are presented assuming the energies of final particles (cms…

High Energy Physics - Phenomenology · Physics 2008-11-26 Yu. M. Bystritskiy , G. V. Fedotovich , F. V. Ignatov , E. A. Kuraev

Hybrid/exotic meson spectroscopy searches at Jefferson Lab require the accurate theoretical description of the production mechanism in peripheral photoproduction. We develop a model for $\pi\Delta$ photoproduction at high energies ($5 \leq…

High Energy Physics - Phenomenology · Physics 2018-02-07 J. Nys , V. Mathieu , C. Fernández-Ramírez , A. Jackura , M. Mikhasenko , A. Pilloni , N. Sherrill , J. Ryckebusch , A. P. Szczepaniak , G. Fox

The experimental and phenomenological status of high energy photoproduction is reviewed. Topics covered include the structure of the photon, production of jets, heavy flavours and prompt photons, rapidity gaps, energy flow and underlying…

High Energy Physics - Experiment · Physics 2009-11-11 J. M. Butterworth , M. Wing

We provide a precise calculation for the contribution of hard near threshold pion electro production to all nucleon structure functions. This framework will allow us to split the required nucleon to pion nucleon transition probability…

High Energy Physics - Phenomenology · Physics 2011-11-04 Thorsten Sachs

Results of the recently developed unitary isobar model (MAID) are presented for the spin asymmetries, structure functions and relevant sum rules in the resonance region. The model describes the presently available data for single-pion…

Nuclear Theory · Physics 2007-05-23 L. Tiator , D. Drechsel , S. S. Kamalov

The present status of kaon photo- and electroproduction on the nucleon is briefly reviewed. Some current important issues in this field are discussed.

Nuclear Theory · Physics 2011-02-18 T. Mart

The (\pi^{-}\Delta^{++}) production on the nucleon by real and virtual photons is discussed as initial step in a simple model approach for the two pion photo- and electroproduction on the nucleon, with emphasis on nucleon resonance…

High Energy Physics - Phenomenology · Physics 2019-08-17 M. Ripani , V. Mokeev , M. Anghinolfi , M. Battaglieri , G. Fedotov , E. Golovach , B. Ishkhanov , M. Osipenko , G. Ricco , V. Sapunenko , M. Taiuti

An effective field theory with hadrons and photons is constructed, where the hadronic parameters are determined by fitting elastic $\pi$N scattering data. The predicted pion-induced $\eta$-production on the nucleon agrees well with the…

Nuclear Theory · Physics 2011-04-15 C. Sauermann , B. L. Friman , W. Nörenberg