New physics particles mixing with mesons: production in the fragmentation chain

Fuente: arXiv
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Autori principali: Kyselov, Yehor, Mrenna, Stephen, Ovchynnikov, Maksym
Natura: Preprint
Pubblicazione: 2025
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author Kyselov, Yehor
Mrenna, Stephen
Ovchynnikov, Maksym
author_facet Kyselov, Yehor
Mrenna, Stephen
Ovchynnikov, Maksym
contents A class of extensions to the Standard Model adds hypothetical long-lived particles (LLPs) that have mass- or kinetic-mixing with neutral mesons, such as pions or rho mesons. The mixing can contribute significantly to the production of LLPs at proton accelerator experiments, and no consistent description of these production modes exists in the literature. In this paper, we develop a framework for studying different LLPs - dark photons, vector mediators coupled to the baryon current, and axion-like particles with different coupling patterns. In particular, we implement the production mechanisms in \texttt{PYTHIA8}, study how the overall flux and kinematic distributions depend on the LLP's mass, and compare various sub-processes where the mixing contributes - proton bremsstrahlung, meson decay, and production in the fragmentation chain. We find that our new description of LLP production predicts an integrated flux that differs from current approaches by one to two orders of magnitude, and highlight the unavoidable theoretical uncertainties coming from poor knowledge of the properties of heavy mesons.
format Preprint
id arxiv_https___arxiv_org_abs_2504_06828
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle New physics particles mixing with mesons: production in the fragmentation chain
Kyselov, Yehor
Mrenna, Stephen
Ovchynnikov, Maksym
High Energy Physics - Phenomenology
A class of extensions to the Standard Model adds hypothetical long-lived particles (LLPs) that have mass- or kinetic-mixing with neutral mesons, such as pions or rho mesons. The mixing can contribute significantly to the production of LLPs at proton accelerator experiments, and no consistent description of these production modes exists in the literature. In this paper, we develop a framework for studying different LLPs - dark photons, vector mediators coupled to the baryon current, and axion-like particles with different coupling patterns. In particular, we implement the production mechanisms in \texttt{PYTHIA8}, study how the overall flux and kinematic distributions depend on the LLP's mass, and compare various sub-processes where the mixing contributes - proton bremsstrahlung, meson decay, and production in the fragmentation chain. We find that our new description of LLP production predicts an integrated flux that differs from current approaches by one to two orders of magnitude, and highlight the unavoidable theoretical uncertainties coming from poor knowledge of the properties of heavy mesons.
title New physics particles mixing with mesons: production in the fragmentation chain
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2504.06828