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arXiv · 2109.05002

Relativistic, model-independent determination of electromagnetic finite-size effects beyond the point-like approximation

M. Di Carlo·M. T. Hansen·N. Hermansson-Truedsson·A. Portelli
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Abstract

We present a relativistic and model-independent method to derive structure-dependent electromagnetic finite-size effects. This is a systematic procedure, particularly well-suited for automatization, which works at arbitrarily high orders in the large-volume expansion. Structure-dependent coefficients appear as zero-momentum derivatives of physical form factors which can be obtained through experimental measurements or auxiliary lattice calculations. As an application we derive the electromagnetic finite-size effects on the pseudoscalar meson mass and leptonic decay amplitude, through orders $\mathcal{O}(1/L^3)$ and $\mathcal{O}(1/L^2)$, respectively. The structure dependence appears at this order through the meson charge radius and the real radiative leptonic amplitude, which are known experimentally.

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M. Di Carlo, M. T. Hansen, N. Hermansson-Truedsson, A. Portelli. 2021-09-10. Relativistic, model-independent determination of electromagnetic finite-size effects beyond the point-like approximation. https://arxiv.org/abs/2109.05002

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