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Related papers: A consistent model for \pi N transition distributi…

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The multipole amplitudes for the N - Delta electromagnetic transition are computed in the framework of the linear sigma model and the chiral chromodielectric model for small and moderate photon virtualities. The models include quark and…

High Energy Physics - Phenomenology · Physics 2008-11-26 Luis Amoreira , Pedro Alberto , Manuel Fiolhais

We introduce a new family of Generalised Parton Distribution models able to fulfil by construction all the theoretical properties imposed by QCD. These models are built on standard Parton Distribution Functions and extended to off-forward…

We present a direct lattice QCD calculation of the $x$-dependence of the pion distribution amplitude (DA), which is performed using the quasi-DA in large momentum effective theory on a domain-wall fermion ensemble at physical quark masses…

High Energy Physics - Lattice · Physics 2024-07-29 Ethan Baker , Dennis Bollweg , Peter Boyle , Ian Cloët , Xiang Gao , Swagato Mukherjee , Peter Petreczky , Rui Zhang , Yong Zhao

We construct a model for the weak pion production off the nucleon, which in addition to the weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$, it includes also some background terms required by chiral…

Nuclear Theory · Physics 2008-11-26 E. Hernandez , J. Nieves , M. Valverde

The transversity generalized parton distributions (tGPDs) of the the pion, involving matrix elements of the tensor bilocal quark current, are analyzed in chiral quark models. We apply the nonlocal chiral models involving a…

High Energy Physics - Phenomenology · Physics 2013-05-29 Alexander E. Dorokhov , Wojciech Broniowski , Enrique Ruiz Arriola

Understanding single pion production reactions on free nucleons is the first step towards a correct description of these processes in nuclei, which are important for signal and background contributions in current and near future accelerator…

High Energy Physics - Phenomenology · Physics 2017-03-29 E. Hernández , J. Nieves

Following the proposal in [1], we study the feasibility to calculate the pion distribution amplitude (DA) from suitably chosen Euclidean correlation functions at large momentum. In our lattice study we employ the novel momentum smearing…

Motivated by the renewed interest in studying the pion production on nuclei with protons at few GeV incident energies, we investigate the pion production in proton-proton collisions over an energy range of 300 $MeV$ to 2 $GeV$. Starting…

Nuclear Theory · Physics 2009-10-30 A. Engel , A. K. Dutt-Mazumder , R. Shyam , U. Mosel

We discuss the two-pion exchange potential which emerges from a box diagram with one nucleon (the spectator) restricted to its mass shell, and the other nucleon line replaced by a subtracted, covariant $\pi N$ scattering amplitude which…

Nuclear Theory · Physics 2008-11-26 M. T. Peña , Franz Gross , Yohanes Surya

This is an English translation of my 1977 Russian preprint. It contains the first explicit definition of the pion distribution amplitude (DA), the expression for the pion form factor asymptotics in terms of the pion DA, and formulates the…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Radyushkin

The associated production of a $J/{\psi}$ and a $\pi$-meson in antiproton-nucleon annihilation is studied in the framework of QCD collinear factorization. In this approach, a hard subprocess responsible for the production of the heavy…

High Energy Physics - Phenomenology · Physics 2016-11-23 B. Pire , K. Semenov-Tian-Shansky , L. Szymanowski

We present here an extension of our model for the pion, which we used previously to calculate its diagonal structure function, to the off-forward case. The imaginary part of the off-forward gamma^* pi -> gamma^* pi scattering amplitude is…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. P. Lansberg , F. Bissey , J. R. Cudell , J. Cugnon , P. Stassart

We investigate threshold pion photoproduction in the framework of heavy baryon chiral perturbation theory. We give the expansion of the electric dipole amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon mass, and…

High Energy Physics - Phenomenology · Physics 2009-09-25 V. Bernard , N. Kaiser , Ulf-G. Meißner

The process of pion axioproduction, $aN\to\pi N$, with an intermediate $\Delta$ resonance is analyzed using baryon chiral parturbation theory. The $\Delta$ resonance is included in two ways: First, deriving the $a\Delta N$-vertices, the…

High Energy Physics - Phenomenology · Physics 2022-03-30 Thomas Vonk , Feng-Kun Guo , Ulf-G. Meißner

We evaluate the cross section for anti-p p -> l+ l- pi0 in the forward direction and for large lepton pair invariant mass. In this kinematical region, the leading-twist amplitude factorises into a short-distance matrix element,…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. P. Lansberg , B. Pire , L. Szymanowski

We calculate the valence quark distribution functions of the $\pi$ meson using the non-relativistic chiral constituent quark model. The $\pi$ wave function is obtained by solving the two-body Schr\"odinger equation within the framework of…

High Energy Physics - Phenomenology · Physics 2023-08-21 Qian Wu , Chengdong Han , Di Qing , Wei Kou , JuJun Xie , Fan Wang , Xurong Chen

In this paper, we develop an approach to calculate the valence-quark quasi parton distribution amplitude (quasi-PDA) and quasi parton distribution function (quasi-PDF) for the pion with a large longitudinal momentum with the functional…

High Energy Physics - Phenomenology · Physics 2025-02-24 Dao-yu Zhang , Chuang Huang , Wei-jie Fu

We report results on the $\pi$-$\gamma$ transition form factor obtained within the hard scattering approach including transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close to the…

High Energy Physics - Phenomenology · Physics 2009-09-25 R. Jakob , P. Kroll , M. Raulfs

Considering, as a limit case, an approximately flat pion distribution amplitude, which is determined from the hardest, in momentum space, solution of the Bethe-Salpeter equation for the pion wave function, we compute the pion transition…

High Energy Physics - Phenomenology · Physics 2020-01-22 D. A. Fagundes , E. G. S. Luna , A. A. Natale , M. Pelaez

The dynamical model of pion electroproduction has been extended to investigate the weak pion production reactions. The predicted cross sections of neutrino-induced pion production reactions are in good agreement with the existing data. We…

Nuclear Theory · Physics 2009-11-10 T. Sato , D. Uno , T. -S. H. Lee