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The electromagnetic current of spin-1 composite particles does not transform properly under rotations if only the valence contribution is considered in the light-front model. In particular, the plus component of the current, evaluated only…

High Energy Physics - Phenomenology · Physics 2010-11-19 J. P. B. C. de Melo , T. Frederico

The violation of the rotational symmetry constraint of the matrix elements of the plus component of the vector current, in the Drell-Yan frame, is studied using an analytical and covariant model of spin-1 composite particle. The…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. P. B. C. de Melo , T. Frederico

The electromagnetic current~$J^+$ for spin-1, is used here to extract the electromagnetic form-factors of a light-front constituent quark model. The charge ($G_0$), magnetic ($G_1$) and quadrupole $G_2$ form factors are calculated using…

High Energy Physics - Phenomenology · Physics 2015-03-04 J. P. B. C. de Melo , Anacé N. da Silva , Clayton S. Mello , T. Frederico

The electromagnetic form factors of a composite vector particle within the light-front formulation of the Mandelstam formula is investigated. In order to extract the form factors from the matrix elements of the plus component of the current…

High Energy Physics - Phenomenology · Physics 2018-12-26 J. P. B. C. de Melo

The issue of the contribution of zero-modes to the light-front projection of the electromagnetic current of phenomenological models of vector particles vertices is addressed in the Drell-Yan frame. Our analytical model of the Bethe-Salpeter…

High Energy Physics - Phenomenology · Physics 2012-02-06 J. P. B. C. de Melo , T. Frederico

The electromagnetic form factor is extracted from both components of the electromagnetic current: J(plus) and J(minus) with a pseudo-scalar coupling of the quarks to the kaon. In the case of J(plus) there is no pair term contribution in the…

High Energy Physics - Phenomenology · Physics 2017-08-23 J. P. B. C. de Melo , Lauro Tomio , T. Frederico

For the vector sector, i.e, mesons with spin-1, the electromagnetic form factors and anothers observables are calculated with the light-front approach. However, the light-front quantum field theory have some problems, for example, the…

High Energy Physics - Phenomenology · Physics 2015-04-28 J. P. B. C. de Melo , Anacé N. da Silva , Clayton S. Mello , T. Frederico

We investigate the electroweak form factors and semileptonic decay rates of pseudoscalar and vector mesons using the light-front constituent quark model. Our method of analytic continuation in the Drell-Yan-West (q^+=q^0+q^3=0) frame to…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ho-Meoyng Choi

The light-front approach is applied to calculate the electromagnetic current for quark-antiquark bound states for the pion. The pion electromagnetic form factor is obtnaide from the "+" and "-" components of the electromagnetic current in…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. P. B. C. de Melo

Numerical calculations are performed and compared to the experimental data for the electromagnetic form factor of the kaon, which is extracted from both components of the electromagnetic current, $J^{+}$ and $J^{-}$, with a pseudo-scalar…

High Energy Physics - Phenomenology · Physics 2007-05-23 Fabiano P. Pereira , J. P. B. C. de Melo , T. Frederico , Lauro Tomio

We analyze the matrix element of the electroweak current between $q \qb$ vector meson states in the framework of a covariant extension of the light-front formalism. The light-front matrix element of a one-body current is naturally…

High Energy Physics - Phenomenology · Physics 2009-11-07 Wolfgang Jaus

Spin-1 particles, is a fundamental bound state for the two quarks, and play a crucial role in elucidating the electromagnetic properties within the realm of hadronic physics. Their intrinsic relativistic nature mandates a quantum field…

High Energy Physics - Phenomenology · Physics 2026-02-18 J. P. B. C. de Melo

While the particle-number-conserving convolution formalism established in the Drell-Yan-West reference frame is frequently used to compute exclusive amplitudes in the light-front quantization, this formalism is limited to only those frames…

High Energy Physics - Phenomenology · Physics 2009-10-31 C. -R. Ji , C. Mitchell

Due to the angular condition in the light-front dynamics (LFD), the extraction of the electromagnetic form factors for spin-1 particles can be uniquely determined taking into account implicitly non-valence and/or the zero-mode contributions…

High Energy Physics - Phenomenology · Physics 2018-05-23 J. P. B. C. de Melo , T. Frederico , Chueng -R. Ji

We apply the light-front reduction of the Bethe-Salpeter equation to matrix elements of the electromagnetic current between bound states. Using a simple (1+1)-dimensional model to calculate form factors, we focus on two cases. In one case,…

High Energy Physics - Phenomenology · Physics 2009-11-07 B. C. Tiburzi , G. A. Miller

In light-front dynamics, form factors are traditionally computed with the "good current" $J^+$ within the Drell-Yan frame $q^+=0$. Due to truncations imposed in practical calculations, the from factor may acquire frame dependence, which is…

High Energy Physics - Phenomenology · Physics 2018-04-02 Yang Li , Pieter Maris , James Vary

We study the radiative transitions between vector and pseudoscalar quarkonia in the light-front Hamiltonian approach, and investigate the effects of using different current component and different reference frames. In practical calculations…

Nuclear Theory · Physics 2020-11-03 Meijian Li

We present the first systematic investigation of the Lorentz covariance of the charge form factor for a strongly coupled scalar theory in (3+1)-dimensions. Our results are based on the first non-perturbative solution of the scalar Yukawa…

High Energy Physics - Phenomenology · Physics 2025-07-22 Wenyu Zhang , Yang Li , James P. Vary

The frame and scale dependence of the pair-term contribution to the electromagnetic form factor of a spin-zero composite system of two-fermions is studied within the Light Front. The form factor is evaluated from the plus-component of the…

Nuclear Theory · Physics 2009-11-07 J. P. B. C. de Melo , T. Frederico , E. Pace , G. Salme`

We study the form factors of vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing a light-front calculation in the $q^+ =0$ frame in parallel with a manifestly covariant calculation, we note the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Bernard L. G. Bakker , Ho-Meoyng Choi , Chueng-Ryong Ji
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