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Main Authors: Bansal, Anshika, Jenkins, Jack, Winney, Daniel
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2512.18909
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author Bansal, Anshika
Jenkins, Jack
Winney, Daniel
author_facet Bansal, Anshika
Jenkins, Jack
Winney, Daniel
contents We study dispersive representations of nonlocal form factors in $K^+ \to π^+ \ell^+ \ell^-$ and $K^+ \to π^+ ν\barν$ decays, with an aim of improving the theoretical description of the spectrum and decay rate of the neutrino mode. Based on unitarity, these representations invoke the $K^+ π^- \to π^+ π^-$ amplitude in $P$-wave and the pion vector form factor. The $P$-wave amplitude can be effectively parameterized within the dispersive Khuri-Treiman framework, and constrained by experimental information on the CP-conserving $K^+ \to π^+ π^+ π^-$ and $K^+ \to π^0 π^0 π^+$ decays. We also emphasize certain relations between charged-lepton and neutrino non-local form factors based on the Operator Product Expansion, which can be used to impose further phenomenological constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2512_18909
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Application of $K \to 3π$ amplitudes to semileptonic kaon decays
Bansal, Anshika
Jenkins, Jack
Winney, Daniel
High Energy Physics - Phenomenology
We study dispersive representations of nonlocal form factors in $K^+ \to π^+ \ell^+ \ell^-$ and $K^+ \to π^+ ν\barν$ decays, with an aim of improving the theoretical description of the spectrum and decay rate of the neutrino mode. Based on unitarity, these representations invoke the $K^+ π^- \to π^+ π^-$ amplitude in $P$-wave and the pion vector form factor. The $P$-wave amplitude can be effectively parameterized within the dispersive Khuri-Treiman framework, and constrained by experimental information on the CP-conserving $K^+ \to π^+ π^+ π^-$ and $K^+ \to π^0 π^0 π^+$ decays. We also emphasize certain relations between charged-lepton and neutrino non-local form factors based on the Operator Product Expansion, which can be used to impose further phenomenological constraints.
title Application of $K \to 3π$ amplitudes to semileptonic kaon decays
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2512.18909