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We analyze a low-energy theorem of threshold pion electroproduction which allows one to determine the charge radius of the pion. We show that at the same order where the radius appears, pion loops induce a correction to the momentum…

Nuclear Theory · Physics 2009-11-06 Véronique Bernard , Norbert Kaiser , Ulf-G. Meißner

We use a method to calculate the hadron's charge radius without model-dependent momentum extrapolations. The method does not require the additional quark propagator inversions on the twisted boundary conditions or the computation of the…

High Energy Physics - Lattice · Physics 2020-04-01 Xu Feng , Yang Fu , Lu-Chang Jin

The dichotomy of the pion as QCD's Goldstone mode and a bound state of massive constituents is easily understood using the Dyson-Schwinger equations. That provides the foundation for an efficacious phenomenology, which correlates the pion's…

Nuclear Theory · Physics 2010-03-04 M. B. Hecht , C. D. Roberts

The nonperturbative, Dyson-Schwinger equation approach to solving QCD provides a straightforward, microscopic description of dynamical chiral symmetry breaking and confinement. It is an ideal tool for the study of pion observables. This is…

High Energy Physics - Phenomenology · Physics 2009-10-28 Craig D. Roberts

The electromagnetic tensor for inclusive electron scattering off the pion, ($W^{\mu\nu}$), for momentum transfers such that $q^+=0$, ($q^+=q^0+q^3$) is shown to obey a sum-rule for the component $W^{++}$. From this sum-rule, one can define…

High Energy Physics - Phenomenology · Physics 2009-07-28 J. P. B. C de Melo , T. Frederico , Lauro Tomio , A. E. Dorokhov

The electromagnetic radius of the charged pion and the transition radius of the neutral pion are calculated in the framework of the nonlocal chiral quark model. It is shown in this model that the contributions of vector mesons to the pion…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. E. Dorokhov , A. E. Radzhabov , M. K. Volkov

A novel method is employed to compute the pion electromagnetic form factor, F_\pi(Q^2), on the entire domain of spacelike momentum transfer using the Dyson-Schwinger equation (DSE) framework in quantum chromodynamics (QCD). The DSE…

Nuclear Theory · Physics 2015-06-16 L. Chang , I. C. Cloet , C. D. Roberts , S. M. Schmidt , P. C. Tandy

We investigate the pion electromagnetic charge radii and mass dropping of the rho meson at finite density. We first calculate the pion charge radii within the framework of the nonlocal chiral quark model from the instanton vacuum both at…

High Energy Physics - Phenomenology · Physics 2011-08-19 Seung-il Nam , Hyun-Chul Kim

We present our results on the electromagnetic form factor of pion over a wide range of $Q^2$ using lattice QCD simulations with Wilson-clover valence quarks and HISQ sea quarks. We study the form factor at the physical point with a lattice…

High Energy Physics - Lattice · Physics 2022-01-07 Xiang Gao , Nikhil Karthik , Swagato Mukherjee , Peter Petreczky , Sergey Syritsyn , Yong Zhao

The electromagnetic form factor of the pion is calculated in the "point-form" of relativistic quantum mechanics using simple, phenomenological wave functions. It is found that the squared charge radius of the pion is predicted one order of…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. Amghar , B. Desplanques , L. Theussl

We develop a formalism to calculate form factor and charge density distribution of pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic…

High Energy Physics - Phenomenology · Physics 2008-11-26 H. R. Grigoryan , A. V. Radyushkin

We calculate the vector and scalar form factors of the pion to two loops in Chiral Perturbation Theory. We estimate the unknown O(p^6) constants using resonance exchange. We make a careful comparison to the available data and determine two…

High Energy Physics - Phenomenology · Physics 2009-10-31 J. Bijnens , G. Colangelo , P. Talavera

Low and high energy properties of the pion are reviewed in the framework of chiral quark models. Particular emphasis is put on the simplest version of the SU(2) NJL model as prototype. The role of gauge invariance in this kind of…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. Ruiz Arriola

Recent results on pion physics from lattice QCD are reviewed. We discuss quark mass dependences of pion mass and decay constant and compare them with the predictions from chiral perturbation theory. In particular we focus on the convergence…

High Energy Physics - Lattice · Physics 2014-11-20 Sinya Aoki

Pion loop fluctuations of the constituent u and d quarks are shown to give only a minute contribution to the intrinsic charge radius of the neutron, under the assumption that the pion-quark coupling constant has its conventional value, with…

High Energy Physics - Phenomenology · Physics 2011-02-01 L. Ya. Glozman , D. O. Riska

We present a comprehensive study of the electromagnetic form factor, the decay constant and the mass of the pion computed in lattice QCD with two degenerate O(a)-improved Wilson quarks at three different lattice spacings in the range…

High Energy Physics - Lattice · Physics 2015-06-16 Bastian B. Brandt , Andreas Juttner , Hartmut Wittig

We study in various chiral models the pion charge radius, $\pi_{e3}$ form factor ratio, $\pi^\circ \to \gamma \gamma$ amplitude, charge pion polarizabilities, $\gamma\gamma \to \pi^\circ \pi^\circ$ amplitude at low energies and the $\pi\pi$…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. D. Scadron

The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the dressed quark-photon vertex to study the low-momentum behavior of the pion electromagnetic form factor. With model…

Nuclear Theory · Physics 2011-07-18 P. Maris , P. C. Tandy

Logarithmic divergences in pion and proton charge radii associated with chiral loops are investigated to assess systematic uncertainties in current lattice determinations of charge radii. The chiral corrections offer a possible solution to…

High Energy Physics - Lattice · Physics 2009-10-22 Derek B. Leinweber , Thomas D. Cohen

We study the self-energy amplitudes for the rho-omega meson system produced by an effective field theory model at the quark level characterized by a finite range quark-quark interaction and an isospin breaking bare quark mass difference…

Nuclear Theory · Physics 2008-11-26 K. L. Mitchell , P. C. Tandy
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