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Complete one-loop electroweak corrections to neutral current Drell-Yan process $p p \to \ell^+\ell^- X$ are presented for the case of longitudinal polarization of initial particles. Cross sections for longitudinally polarized protons allow…

High Energy Physics - Phenomenology · Physics 2023-05-10 S. Bondarenko , Ya. Dydyshka , L. Kalinovskaya , R. Sadykov , V. Yermolchyk

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

For a relativistic system of two scalar particles, we find the Bethe-Salpeter amplitude in Minkowski space and use it to compute the electromagnetic form factor. The comparison with Euclidean space calculation shows that the Wick rotation…

High Energy Physics - Phenomenology · Physics 2010-04-21 J. Carbonell , V. A. Karmanov , M. Mangin-Brinet

The matrix elements of electroweak currents which occur in exclusive decays of heavy hadrons are evaluated in the nonperturbative light-cone Fock representration. In general, each semileptonic exclusive decay amplitude receives two…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , D. S. Hwang

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 present a relativistic point-form approach for the calculation of electroweak form factors of few-body bound states that leads to results which resemble those obtained within the covariant light-front formalism of Carbonell et al. Our…

High Energy Physics - Phenomenology · Physics 2015-05-30 María Gómez-Rocha , Elmar. P. Biernat , Wolfgang Schweiger

The pion electromagnetic form factor is calculated with a light-front quark model. The "plus" and "minus" component of the electromagnetic current are used to calculate the electromagnetic form factor in the Breit frame with two models for…

High Energy Physics - Phenomenology · Physics 2009-11-10 J. P. B. C. de Melo

We calculate the transition form factor between vector and pseudoscalar quarkonia in both the timelike and the spacelike region using light-front dynamics. We investigate the frame dependence of the form factors for heavy quarkonia with…

Nuclear Theory · Physics 2019-08-19 Meijian Li , Yang Li , Pieter Maris , James P. Vary

We investigate the transition form factors between nucleon and $\Delta$(1232) particles by using a covariant quark-spectator-diquark field theory model in (3+1) dimensions. Performing a light-front calculation in parallel with the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jianghao Yu , Teng Wang , Chueng-Ryong Ji , Bo-Qiang Ma

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

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

Naive light-front quantization, carried out by a light-front energy integration of covariant amplitudes, is not guaranteed to generate the corresponding Feynman amplitudes. In an explicit example we show that the nonvalence contribution to…

High Energy Physics - Theory · Physics 2009-10-31 B. L. G. Bakker , Chueng-Ryong Ji

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

The connection between the Feynman triangle diagram and the light-front formalism for spin-0 and spin-1 two-fermion systems is analyzed. It is shown that in the limit q+ = 0 the form factors for both spin-0 and spin-1 systems can be…

High Energy Physics - Phenomenology · Physics 2009-11-07 D. Melikhov , S. Simula

Even though the Drell-Yan-West formulation is the most rigorous and well-established framework to compute the exclusive processes, its utility has been limited only to the spacelike region because of the intrinsic kinematic constraint…

High Energy Physics - Phenomenology · Physics 2009-10-31 Ho-Meoyng Choi , Chueng-Ryong Ji

The kaon electromagnetic form factor is calculated within a light-front constituent quark model (LFCQM). The electromagnetic components of the current are extracted from the Feynman triangle diagram within the light-front approach. We also…

High Energy Physics - Phenomenology · Physics 2015-06-11 Edson O. da Silva , J. P. B. C. de Melo , Victo S. Filho , Bruno El-Bennich

Form factors for $P\to P$ and $P\to V$ transitions due to the valence-quark configuration are calculated directly in the physical time-like range of momentum transfer within the light-front quark model. It is pointed out that the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Hai-Yang Cheng

We study the analytic structure of light-front wave functions (LFWFs) and its consequences for hadron form factors using an explicitly Lorentz-invariant formulation of the front form. The normal to the light front is specified by a general…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , J. R. Hiller , D. S. Hwang , V. A. Karmanov

The divergences appearing in the 3+1 dimensional fermion-loop calculations are often regulated by smearing the vertices in a covariant manner. Performing a parallel light-front calculation, we corroborate the similarity between the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bernard L. G. Bakker , Ho-Meoyng Choi , Chueng-Ryong Ji

The relativistic approach to electroweak properties of two-particle composite systems developed in Ref. [A.F.Krutov, V.E.Troitsky, Phys.Rev.C. 65 (2002) 045501] is generalized here to the case of nonzero spin. In developed technique the…

High Energy Physics - Phenomenology · Physics 2009-02-06 A. F. Krutov , V. E. Troitsky