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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 contribution of the light-front valence wave function to the electromagnetic current of spin-1 composite particles is not enough to warranty the proper transformation of the current under rotations. The naive derivation of the plus…

High Energy Physics - Phenomenology · Physics 2012-02-01 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 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

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

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

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

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 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

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 compute the "+" component of the electromagnetic current of a composite spin-one two-fermion system for vanishing momentum transfer component $q^+=q^0+q^3$. In particular, we extract the nonvanishing pair production amplitude on the…

High Energy Physics - Phenomenology · Physics 2009-10-31 J. P. B. C de Melo , T. Frederico , H. W. L. Naus , P. U. Sauer

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

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`

The frame dependence of the pair-term contribution to the electromagnetic form factor of the pion is studied within the Light Front approach. A symmetric ansatz for the pion Bethe-Salpeter amplitude with a pseudo scalar coupling of the…

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

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

The rho-meson eletromagnetic form factors are calculated, both in covariant and light-front framework with constituintes quarks. The effect of the breakdown rotational symmetry for the one-body current operador in the null-plane is…

Nuclear Theory · Physics 2008-11-26 J. P. B. C de Melo , T. Frederico

The electromagnetic form factors of spin-1/2 particles are known, but due to historical reasons only half of them are found in many textbooks. Given the importance of the general result, its model independence, its connection to discrete…

Physics Education · Physics 2009-11-10 Marek Nowakowski , E. A. Paschos , J. M. Rodriguez

Light front formalism for composite systems is presented. Derivation of equations for bound state and scattering problems are given. Methods of constructing of elastic form factors and scattering amplitudes of composite particles are…

High Energy Physics - Theory · Physics 2008-11-26 V. R. Garsevanishvili , A. A. Khelashvili , Z. R. Menteshashvili , M. S. Nioradze

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
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