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arXiv · 2309.09695

Triangle and box diagrams in coupled-channel systems from the chiral Lagrangian

Tobias Isken·Xiao-Yu Guo·Yonggoo Heo·Csaba L. Korpa·Matthias F. M. Lutz
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Abstract

We perform an analysis of triangle- and box-loop contributions to the generalized potential in the scattering of Goldstone bosons off the J^P= 0^- and 1^- charmed mesons. Particular emphasis is put on the use of on-shell mass parameters in such contributions in terms of a renormalization scheme that ensures the absence of power-counting violating terms. This is achieved with a systematically extended set of Passarino--Veltman basis functions, that leads to manifest power-counting conserving one-loop expressions and avoids the occurrence of superficial kinematical singularities. Compact expressions to chiral order three and four are presented that are particularly useful in coding such coupled-channel systems. Our formal results are generic and prepare analogous computations for other systems, like meson-baryon scattering from the chiral Lagrangian.

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Tobias Isken, Xiao-Yu Guo, Yonggoo Heo, Csaba L. Korpa, Matthias F. M. Lutz. 2023-09-18. Triangle and box diagrams in coupled-channel systems from the chiral Lagrangian. https://arxiv.org/abs/2309.09695

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