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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 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 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 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

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

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

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

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

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

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

A constituent quark model is developed for an arbitrary light- cone direction \omega. Form factors are obtained from free one-body electromagnetic current matrix elements. They are found to be \omega- independent for spin-0 mesons, the…

High Energy Physics - Phenomenology · Physics 2009-10-28 H. J. Weber , Xiaoming Xu

We study the structure of the $\rho$-meson within a light-front model with constituent quark degrees of freedom. We calculate electroweak static observables: magnetic and quadrupole moments, decay constant and charge radius. The…

High Energy Physics - Phenomenology · Physics 2015-03-16 Clayton S. Mello , Anacé N. da Silva , J. P. B. C. de Melo , T. Frederico

In this work, the electromagnetic and gravitational form factors of a spin-$3/2$ particle, $\Delta$ resonance, are simultaneously calculated with the help of a relativistic covariant quark-diquark approach. The two kinds of form factors are…

High Energy Physics - Phenomenology · Physics 2022-01-24 Dongyan Fu , Bao-Dong Sun , Yubing Dong

Using local gauge invariance in the form of the Ward-Takahashi identity and the fact that properly constructed current operators must be free of kinematic singularities, it is shown that the magnetic moment $\mu$ and the quadrupole moment…

Nuclear Theory · Physics 2019-08-23 Helmut Haberzettl

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

The electromagnetic form factors of the $\rho$ meson are evaluated adopting a relativistic constituent quark model based on the light-front formalism, and using a meson wave function with the high-momentum tail generated by the…

High Energy Physics - Phenomenology · Physics 2016-09-01 F. Cardarelli , I. L. Grach , I. M. Narodetskii , G. Salme' , S. Simula

Here we present preliminary results for the evaluation of the electromagnetic form factors for the lowest-lying negative-parity, spin-$\frac{1}{2}$ nucleons, namely the $S_{11}(1535)$ and $S_{11}(1650)$, through the use of the variational…

High Energy Physics - Lattice · Physics 2014-12-16 Benjamin Owen , Waseem Kamleh , Derek Leinweber , Selim Mahbub , Benjamin Menadue

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

A parameter-free evaluation of the $N - \Delta$ electromagnetic transition form factors is carried out in a light-front constituent quark model, based on $N$ and $\Delta$ eigenstates of a mass operator which reproduces a large set of hadron…

Nuclear Theory · Physics 2009-10-28 F. Cardarelli , E. Pace , G. Salme' , S. Simula
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