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arXiv · hep-ph/9903349

Covariant amplitudes for mesons

Jie-Jie Zhu·Mu-Lin Yan
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Abstract

We show how to construct covariant amplitudes for processes involving higher spins in this paper. First we give the explicit expressions of Rarita-Schwinger wave functions and propagators for bosons with spins, then kinematic singularity free 3-leg effective vertexes are derived and given in a list. Equivalence relations are worked out to get these independent vertexes. Constraints of space reflection symmetry and boson symmetry are considered and shown in a explicit way. Some helicity amplitudes for two-body decays in center of frame are calculated. Finally the covariant helicity amplitudes for the process $a_1\to π^+π^+π^-$ are constructed to illustrate how to include background (1PI) amplitudes. Both background amplitudes and resonance amplitudes are needed to give reliable descriptions to high energy reactions.

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Jie-Jie Zhu, Mu-Lin Yan. 1999-03-15. Covariant amplitudes for mesons. https://arxiv.org/abs/hep-ph/9903349

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