Indirect new physics effects on $σ_{\rm had}$ confront the $(g-2)_μ$ window discrepancies and the CMD-3 result

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Hauptverfasser: Darmé, Luc, di Cortona, Giovanni Grilli, Nardi, Enrico
Format: Preprint
Veröffentlicht: 2022
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author Darmé, Luc
di Cortona, Giovanni Grilli
Nardi, Enrico
author_facet Darmé, Luc
di Cortona, Giovanni Grilli
Nardi, Enrico
contents Recent lattice determinations of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment $a_μ^{\rm HVP}$ have confirmed the discrepancy with the data-driven dispersive method. In the meanwhile the CMD-3 collaboration has reported a result for the $e^+e^-\to π^+π^-$ cross section considerably larger than previous experimental results (and close to the lattice determinations) exacerbating the discordance between different $e^+e^-$ datasets. We explore to what extent these disagreements can be accounted for by some new physics effect altering selectively the individual experimental determinations of $σ(e^+e^- \to\;$hadrons). We find that specific effects of GeV-scale new particles are able to shift upwards the KLOE and BaBar results in the low and intermediate energy windows, while leaving unaffected the CMD-3 energy scan. Although these new physics effects cannot fully explain all the discrepancies among the different $σ(e^+e^- \to\;$hadrons) datasets, they succeed in mitigating the overall tension between data-driven and lattice estimates of $a_μ^{\rm HVP}$. Remarkably, the additional loop corrections involving the new particles concur to solve the residual discrepancy with the experimental value of $(g-2)_μ$.
format Preprint
id arxiv_https___arxiv_org_abs_2212_03877
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Indirect new physics effects on $σ_{\rm had}$ confront the $(g-2)_μ$ window discrepancies and the CMD-3 result
Darmé, Luc
di Cortona, Giovanni Grilli
Nardi, Enrico
High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
Recent lattice determinations of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment $a_μ^{\rm HVP}$ have confirmed the discrepancy with the data-driven dispersive method. In the meanwhile the CMD-3 collaboration has reported a result for the $e^+e^-\to π^+π^-$ cross section considerably larger than previous experimental results (and close to the lattice determinations) exacerbating the discordance between different $e^+e^-$ datasets. We explore to what extent these disagreements can be accounted for by some new physics effect altering selectively the individual experimental determinations of $σ(e^+e^- \to\;$hadrons). We find that specific effects of GeV-scale new particles are able to shift upwards the KLOE and BaBar results in the low and intermediate energy windows, while leaving unaffected the CMD-3 energy scan. Although these new physics effects cannot fully explain all the discrepancies among the different $σ(e^+e^- \to\;$hadrons) datasets, they succeed in mitigating the overall tension between data-driven and lattice estimates of $a_μ^{\rm HVP}$. Remarkably, the additional loop corrections involving the new particles concur to solve the residual discrepancy with the experimental value of $(g-2)_μ$.
title Indirect new physics effects on $σ_{\rm had}$ confront the $(g-2)_μ$ window discrepancies and the CMD-3 result
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
High Energy Physics - Lattice
url https://arxiv.org/abs/2212.03877