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arXiv · 2209.05076

A measurement of the $K^{+} \to \pi^{+} \mu^{+} \mu^{-}$ decay

NA62 Collaboration
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Abstract

A sample of $2.8 \times 10^4$ $K^{+} \to \pi^{+} \mu^{+} \mu^{-}$ candidates with negligible background was collected by the NA62 experiment at the CERN SPS in 2017--2018. The model-independent branching fraction is measured to be $(9.15 \pm 0.08)\times 10^{-8}$, a factor three more precise than previous measurements. The decay form factor is presented as a function of the squared dimuon mass. A measurement of the form factor parameters and their uncertainties is performed using a description based on Chiral Perturbation Theory at $\mathcal{O}(p^6)$.

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NA62 Collaboration. 2022-09-12. A measurement of the $K^{+} \to \pi^{+} \mu^{+} \mu^{-}$ decay. https://doi.org/10.1007/jhep11(2022)011

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