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The pion transition form factor $G(q^2)$ is computed on the entire domain of spacelike and timelike momenta using a quantum field theory continuum approach. In analytical continuation of the function $G(Q^2)$ we utilized the Gauge Technique…

High Energy Physics - Phenomenology · Physics 2020-08-05 V. Sauli

We perform a lattice QCD calculation of the \pi^0\to\gamma\gamma transition form factor and the associated decay width. We use a Euclidean time integral of the relevant three-point function to compute the decay amplitude for two-photon…

High Energy Physics - Lattice · Physics 2012-11-13 Xu Feng , Sinya Aoki , Hidenori Fukaya , Shoji Hashimoto , Takashi Kaneko , Jun-ichi Noaki , Eigo Shintani

We examine the role of O(\alpha_s) perturbative corrections to the pion elastic form factor F_\pi(Q^2). We express the quark current three-point function in terms of light cone variables and use Borel transformation to simultaneously model…

High Energy Physics - Phenomenology · Physics 2014-11-17 Adam Szczepaniak , Anatoly Radyushkin , Chueng-Ryong Ji

Electromagnetic form factors of proton and neutron, obtained from a new fit of data, are presented. The proton form factors are obtained from a simultaneous fit to the ratio $\mu_p G_{Ep}/G_{Mp}$ determined from polarization transfer…

High Energy Physics - Phenomenology · Physics 2009-07-09 W. M. Alberico , S. M. Bilenky , C. Giunti , K. M. Graczyk

Using a three-dimensional formalism that includes relativistic kinematics, the effects of negative-energy states, approximate boosts of the two-body system, and current conservation, we calculate the electromagnetic form factors of the…

Nuclear Theory · Physics 2009-04-17 D. R. Phillips , S. J. Wallace , N. K. Devine

A lattice determination of the form factor and decay constants for the semileptonic decay of heavy pseudoscalar (PS) mesons at zero recoil is presented from which the soft pion relation is satisfied. Chiral extrapolation of the form factor…

High Energy Physics - Lattice · Physics 2015-06-25 UKQCD Collaboration , K. C. Bowler , C. M. Maynard , L. Lellouch , J. Nieves , D. G. Richards , L. Del Debbio , J. M. Flynn , V. I. Lesk

We discuss a novel and simple parametrisation of the pion vector form factor that transparently connects spacelike and timelike regions of the momentum transfer $q^2$. Our parametrisation employs the framework of conformal mapping and…

High Energy Physics - Phenomenology · Physics 2025-02-12 Matthew Kirk , Bastian Kubis , Méril Reboud , Danny van Dyk

As a consequence of dynamical chiral symmetry breaking the pion Bethe-Salpeter amplitude necessarily contains terms proportional to gamma_5 gamma.P and gamma_5 gamma.k, where k is the relative and P the total momentum of the constituents.…

Nuclear Theory · Physics 2008-11-26 Pieter Maris , Craig D. Roberts

We study the anomalous electromagnetic pion form factor $F_{\pi^0\gamma^*\gamma^*}$ with a set of holographic models. By comparing with the measured value of the linear slope, some of these models can be ruled out. From the remaining models…

High Energy Physics - Phenomenology · Physics 2011-05-19 Luigi Cappiello , Oscar Cata , Giancarlo D'Ambrosio

We present a precise calculation of the pion form factor using overlap fermions on seven ensembles of 2+1-flavor domain-wall configurations with pion masses varying from 139 to 340 MeV. Taking advantage of the fast Fourier transform and…

High Energy Physics - Phenomenology · Physics 2021-10-13 Gen Wang , Jian Liang , Terrence Draper , Keh-Fei Liu , Yi-Bo Yang

Experimental data of the pion charge form factor are well represented by Poincar\'e invariant constituent-quark phenomenology depending on two parameters, a confinement scale and an effective constituent--quark mass. Pion states are…

Nuclear Theory · Physics 2009-11-10 F. Coester , W. N. Polyzou

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

A unified set of predictions for pion and kaon elastic electromagnetic and gravitational form factors is obtained using a symmetry-preserving truncation of each relevant quantum field equation. A key part of the study is a description of…

High Energy Physics - Phenomenology · Physics 2023-11-28 Yin-Zhen Xu , Minghui Ding , Khépani Raya , Craig D. Roberts , José Rodríguez-Quintero , Sebastian M. Schmidt

Using the PCAC relation, we derive a compact formula for the pion decay constant $F_{\pi}$ in the nonlocal chiral quark model. For practical calculations this formula may be used both in the Minkowski and in the Euclidean space. For the…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Bzdak , M. Praszalowicz

We discuss the pion form factor calculation in QCD.We shortly consider the main points of the nonlocal condensate QCD sum rule approach and show its results for the pion form factor, $F_\pi(Q^2)$. These results are compared with predictions…

High Energy Physics - Phenomenology · Physics 2015-05-20 Alexander P. Bakulev

Separated longitudinal and transverse structure functions for the reaction 1H(e,eprime pi+)n were measured in the momentum transfer region Q2=0.6-1.6 (GeV/c)**2 at a value of the invariant mass W=1.95 GeV. New values for the pion charge…

Nuclear Experiment · Physics 2009-04-15 J. Volmer

We obtain the electromagnetic form factors of the $\gamma N\Delta$ transition by analyzing recent pion-electroproduction data using a fully relativistic dynamical model. Special care is taken to satisfy Ward-Takahashi identities for the…

Nuclear Theory · Physics 2010-01-18 G. L. Caia , V. Pascalutsa , J. A. Tjon , L. E. Wright

We obtain the distribution amplitude (DA) of the pion from its light-front wave functions in the basis light-front quantization framework. This light-front wave function of the pion is given by the lowest eigenvector of a light-front…

High Energy Physics - Phenomenology · Physics 2021-11-24 Chandan Mondal , Sreeraj Nair , Shaoyang Jia , Xingbo Zhao , James P. Vary

The pion structure function is investigated in a simple model, where pion and constituent quark fields are coupled through the simplest pseudoscalar coupling. The imaginary part of the forward gamma* pi-> gamma* pi scattering amplitude is…

High Energy Physics - Phenomenology · Physics 2009-11-07 F. Bissey , J. R. Cudell , J. Cugnon , M. Jaminon , J. P. Lansberg , P. Stassart

We use a version of the instant-form relativistic quantum mechanics of composite systems to obtain the gravitational form factors of the pion in a common approach to its electroweak and gravitational properties. In the preceding work…

High Energy Physics - Phenomenology · Physics 2022-09-16 A. F. Krutov , V. E. Troitsky