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arXiv · 2110.15765

Structure-Dependent Electromagnetic Finite-Size Effects

Matteo Di Carlo·Maxwell T. Hansen·Nils Hermansson-Truedsson·Antonin Portelli
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Abstract

We present a model-independent and relativistic approach to analytically derive electromagnetic finite-size effects beyond the point-like approximation. The key element is the use of electromagnetic Ward identities to constrain vertex functions, and structure-dependence appears via physical form-factors and their derivatives. We apply our general method to study the leading finite-size structure-dependence in the pseudoscalar mass (at order $1/L^3$) as well as in the leptonic decay amplitudes of pions and kaons (at order $1/L^2$). Knowledge of the latter is essential for Standard Model precision tests in the flavour physics sector from lattice simulations.

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Matteo Di Carlo, Maxwell T. Hansen, Nils Hermansson-Truedsson, Antonin Portelli. 2021-10-29. Structure-Dependent Electromagnetic Finite-Size Effects. https://arxiv.org/abs/2110.15765

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