Electroweak splitting functions in the Standard Model and beyond

Fuente: arXiv
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Autores principales: Dittmaier, Stefan, Reyer, Max
Formato: Preprint
Publicado: 2025
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author Dittmaier, Stefan
Reyer, Max
author_facet Dittmaier, Stefan
Reyer, Max
contents We derive quasi-collinear factorization formulas in generic spontaneously broken gauge theories with scalars, fermions, and vector bosons. Specifically, we obtain polarized leading-order splitting functions for all possible final-state and initial-state 1->2 processes in the considered gauge theory. The main complication lies in the presence of mass-singular terms in longitudinal polarization vectors, prohibiting the direct application of the usual factorization procedure known from Quantum Electrodynamics and Quantum Chromodynamics. We overcome this issue with two different strategies, using gauge invariance and Ward identities as guiding principle. Our derivations do not use any explicit component-wise parametrizations of momenta and wave functions and bear no reference to a particular Lorentz frame. Furthermore, our results are valid for completely general definitions of the spin reference axes of the individual external particles. The various massless limits, the special case of the Electroweak Standard Model, the reproduction of existing literature results, and symmetry relations among our splitting functions are discussed in detail.
format Preprint
id arxiv_https___arxiv_org_abs_2507_06568
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electroweak splitting functions in the Standard Model and beyond
Dittmaier, Stefan
Reyer, Max
High Energy Physics - Phenomenology
We derive quasi-collinear factorization formulas in generic spontaneously broken gauge theories with scalars, fermions, and vector bosons. Specifically, we obtain polarized leading-order splitting functions for all possible final-state and initial-state 1->2 processes in the considered gauge theory. The main complication lies in the presence of mass-singular terms in longitudinal polarization vectors, prohibiting the direct application of the usual factorization procedure known from Quantum Electrodynamics and Quantum Chromodynamics. We overcome this issue with two different strategies, using gauge invariance and Ward identities as guiding principle. Our derivations do not use any explicit component-wise parametrizations of momenta and wave functions and bear no reference to a particular Lorentz frame. Furthermore, our results are valid for completely general definitions of the spin reference axes of the individual external particles. The various massless limits, the special case of the Electroweak Standard Model, the reproduction of existing literature results, and symmetry relations among our splitting functions are discussed in detail.
title Electroweak splitting functions in the Standard Model and beyond
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2507.06568