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Related papers: The pion electromagnetic form-factor in a QCD-insp…

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A unified description of spacelike and timelike hadron form factors within a light-front model was successfully applied to the pion. The model is extended to the nucleon to study the role of $q \bar q$ pair production and of nonvalence…

High Energy Physics - Phenomenology · Physics 2008-11-26 E. Pace , G. Salme` , T. Frederico , S. Pisano , J. P. B. C. de Melo

The electromagnetic form factor of the kaon meson is calculated in the light-cone formalism of the relativistic constituent quark model. The calculated $K^+$ form factor is consistent with almost all of the available experimental data at…

High Energy Physics - Phenomenology · Physics 2007-05-23 Bo-Wen Xiao , Xin Qian , Bo-Qiang Ma

We present a detailed investigation of the spacelike pion's electromagnetic form factor using three-point QCD sum rules that exclusively involve nonlocal condensates. Our main methodological tools are a spectral density which includes…

High Energy Physics - Phenomenology · Physics 2009-06-25 A. P. Bakulev , A. V. Pimikov , N. G. Stefanis

We discuss the nonleading, ``soft" contribution to the pion form factor at intermediate momentum transfer within operator product expansion approach. We argue, that the corresponding contribution can temporarily {\bf simulate} the leading…

High Energy Physics - Phenomenology · Physics 2009-09-25 A. Zhitnitsky

Using a holographic dual model of QCD, we compute the pion electromagnetic form factor F_pi(Q^2) in the spacelike momentum transfer region, as well as pion couplings to vector mesons g_rho^(n) pi pi. Spontaneous and explicit chiral symmetry…

High Energy Physics - Phenomenology · Physics 2008-11-26 Herry J. Kwee , Richard F. Lebed

We compute the electromagnetic form factors of the nucleon in the Poincare-covariant Faddeev framework based on the Dyson-Schwinger equations of QCD. The general expression for a baryon's electromagnetic current in terms of three…

High Energy Physics - Phenomenology · Physics 2011-08-08 Gernot Eichmann

The QCD evolution of the pion distribution amplitude (DA) $\phi_\pi(x,Q^2)$ is computed for several commonly used models. Our analysis includes the nonperturbative form predicted by light-front holographic QCD, thus combining the…

High Energy Physics - Phenomenology · Physics 2011-08-12 Stanley J. Brodsky , Fu-Guang Cao , Guy F. de Teramond

We discuss the evaluation of the transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon…

High Energy Physics - Phenomenology · Physics 2019-06-21 N. G. Stefanis

We study the photon-to-meson transition form factors (TFFs) F_{M \gamma}(Q^2) for gamma gamma^* \to M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads…

High Energy Physics - Phenomenology · Physics 2011-11-02 Stanley J. Brodsky , Fu-Guang Cao , Guy F. de Teramond

We present the current status of our lattice calculation of the electromagnetic form factor of the pion with two flavours of non-perturbatively O(a)-improved Wilson fermions. Using twisted boundary conditions and stochastic sources we…

High Energy Physics - Lattice · Physics 2013-01-17 Bastian B. Brandt , Andreas Juttner , Hartmut Wittig

The pion form factor is calculated in the framework of the charge-conjugation invariant Covariant Spectator Theory. This formalism is established in Minkowski space and the calculation is set up in momentum space. In a previous calculation…

High Energy Physics - Phenomenology · Physics 2015-10-27 Elmar P. Biernat , Franz Gross , M. T. Peña , Alfred Stadler

We study consistently the pion's static observables and the elastic and \gamma*\gamma -> \pi^0 transition form factors within a light-front model. Consistency requires that all calculations are performed within a given model with the same…

Nuclear Theory · Physics 2013-01-30 B. El-Bennich , J. P. B. C. de Melo , T. Frederico

The electromagnetic and gravitational form factors of the nucleon are studied simultaneously using a covariant quark-diquark approach, and the pion cloud effect on the form factors is explicitly discussed. In this study, the electromagnetic…

High Energy Physics - Phenomenology · Physics 2025-08-14 Jiaqi Wang , Dongyan Fu , Yubing Dong

We investigate the pion and kaon (pi^+, K^+, K^0) electromagnetic form factors in the space-like region: Q^2 ~< 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N_c limit. Explicit flavor…

High Energy Physics - Phenomenology · Physics 2008-11-26 Seung-il Nam , Hyun-Chul Kim

We use the QCD instanton vacuum model to discuss the emergence of the light scalar and vector mesons on the light front. We take into account both the instanton and anti-instanton single and molecular interactions on the light quarks, in…

High Energy Physics - Phenomenology · Physics 2024-09-17 Wei-Yang Liu , Edward Shuryak , Ismail Zahed

The $\Delta(1232) \to \gamma^\ast N$ magnetic dipole form factor ($G_M^\ast$) is described here within a new covariant model that combines the valence quark core together with the pion cloud contributions. The pion cloud term is…

High Energy Physics - Phenomenology · Physics 2016-02-12 G. Ramalho , M. T Pena , J. Weil , H. van Hees , U. Mosel

In this paper we calculate the power corrections to the pion transition form factor within the framework of perturbative QCD approach on the basis of $k_T$ factorization. The power suppressed contributions from higher twist pion wave…

High Energy Physics - Phenomenology · Physics 2019-08-07 Yue-Long Shen , Zhi-Tian Zou , Ying Li

The factorization theorem for exclusive processes in perturbative QCD predicts the behavior of the pion electromagnetic form factor $F(t)$ at asymptotic spacelike momenta $t(=-Q^2)<0$. We address the question of the onset energy using a…

High Energy Physics - Phenomenology · Physics 2012-06-01 B. Ananthanarayan , Irinel Caprini , I. Sentitemsu Imsong

We perform a nonperturbative lattice calculation of the complex phase and modulus of the pion form factor in the timelike momentum region using the finite-volume technique. We use two ensembles of 2+1-flavor overlap fermion at pion masses…

High Energy Physics - Lattice · Physics 2015-03-18 Xu Feng , Sinya Aoki , Shoji Hashimoto , Takashi Kaneko

In this study, we employ a modified soft-wall holographic model with four flavors to investigate the meson spectra, decay constants, electromagnetic form factors, and charge radius of various mesons. We obtain the spectra for vector, axial…

High Energy Physics - Phenomenology · Physics 2023-08-30 Hiwa A. Ahmed , Yidian Chen , Mei Huang