Lorentz Invariance and the Kinematic Structure of Vertex Functions

Durand, Loyal; DeCelles, Paul C.; Marr, Robert B.

doi:10.1103/physrev.126.1882

Cited by 122 publications

(42 citation statements)

References 19 publications

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“…The result is unsurprisingly similar to that in Ref. [11]. For bosons, spin n a n b 2 = 0 2= + 1 tot…”

Section: H the Helicity Methods [9]supporting

confidence: 82%

“…The z-axis lies along the beam and q~ is measured from the arbitrary x-axis. The current matrix element relevant for the one-photon process is [11,12] We consider final states for which we can use parity, time reversal and charge conjugation invariance [10]. Tests of these principles form a popular, but separate, subject [13].…”

Section: H the Helicity Methods [9]mentioning

confidence: 99%

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Quasi two bodye + e ? annihilation

Krämer

Walsh

1973

Z. Physik

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We present the helicity formalism for e + e-annihilation into two-body resonance states, and show how to systematically extract the magnitudes and relative phases of the form factors present in the one-photon exchange approximation. This entails measurement of one-particle density matrices and certain polarization correlations in the final state. We discuss, as an example, the vector meson dominance expectations for annihilation into meson resonances and show how this model can be tested.

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“…The result is unsurprisingly similar to that in Ref. [11]. For bosons, spin n a n b 2 = 0 2= + 1 tot…”

Section: H the Helicity Methods [9]supporting

confidence: 82%

Section: H the Helicity Methods [9]mentioning

confidence: 99%

Quasi two bodye + e ? annihilation

Krämer

Walsh

1973

Z. Physik

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“…For convenience we work in a particular frame, but the result is covariant. The relationship between helicity amplitudes and multipoles is prescribed in [55], whence we eliminate the arbitrary form-factors in favour of the multipole form-factors.…”

Section: Discussionmentioning

confidence: 99%

“…First we will find the defining relation for multipole amplitudes in terms of helicity amplitudes. This is done in analogy with Durand [55], but rather than working in the Breit frame we choose to work in the rest frame of the decaying particle. The results are Lorentz covariant so this choice of frame is irrelevant.…”

Section: Appendix A: Multipole Decompositionmentioning

confidence: 99%

Radiative transitions in charmonium from lattice QCD

2006

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Radiative transitions between charmonium states offer an insight into the internal structure of heavy-quark bound states within QCD. We compute, for the first time within lattice QCD, the transition form-factors of various multipolarities between the lightest few charmonium states. In addition, we compute the experimentally unobservable, but physically interesting vector form-factors of the ηc, J/ψ and χc0.To this end we apply an ambitious combination of lattice techniques, computing three-point functions with heavy domain wall fermions on an anisotropic lattice within the quenched approximation.With an anisotropy ξ = 3 at as ∼ 0.1 fm we find a reasonable gross spectrum and a hyperfine splitting ∼ 90MeV, which compares favourably with other improved actions.In general, after extrapolation of lattice data at non-zero Q 2 to the photopoint, our results agree within errors with all well measured experimental values. Furthermore, results are compared with the expectations of simple quark models where we find that many features are in agreement; beyond this we propose the possibility of constraining such models using our extracted values of physically unobservable quantities such as the J/ψ quadrupole moment.We conclude that our methods are successful and propose to apply them to the problem of radiative transitions involving hybrid mesons, with the eventual goal of predicting hybrid meson photoproduction rates at the GlueX experiment.

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“…(1) and Eq. (5) are related through a sequence of Lorentz transformations and consequent Wigner rotation angles [7][8][9][10][11][12].…”

mentioning

confidence: 99%

γNΔform factors and Wigner rotations

Slaughter

2009

Phys. Rev. C

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For more than 50 years the γ nucleon resonance isobar transition form factors G * M (q 2 ), G * E (q 2 ), and G * C (q 2 ) have been studied experimentally, theoretically, and phenomenologically. Although there has been substantial progress in understanding their behavior, there remains much work to be done. The resonance mass position and width remain ambiguous. A major tool used in many investigations is the Jones-Scadron rest frame parametrization of the three N γ form factors. We point out that many studies utilizing this parametrization and related formulations and which utilize the rest frame (c.m. frame) may not account for Wigner rotations and the consequent helicity mixing that ensues when the is not at rest (lab frame) thus adversely affecting the accurate and precise determination of these form factors.

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Lorentz Invariance and the Kinematic Structure of Vertex Functions

Cited by 122 publications

References 19 publications

Quasi two bodye + e ? annihilation

Quasi two bodye + e ? annihilation

Radiative transitions in charmonium from lattice QCD

γNΔform factors and Wigner rotations

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