Flavour anomalies and the muon g − 2 from feebly interacting particles

• Published in: The journal of high energy physics Vol. 2022; no. 3; pp. 85 - 32
• Main Authors: Darmé, Luc, Fedele, Marco, Kowalska, Kamila, Sessolo, Enrico Maria
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2022; Springer Nature B.V; SpringerOpen
• Subjects: Anomalies; Beyond Standard Model; Classical and Quantum Gravitation; Collaboration; Effective Field Theories; Elementary Particles; Flavors; High energy physics; Light; Magnetic moments; Muons; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Vector currents; Effective Field Theories; Beyond Standard Model
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP03(2022)085

A bstract We perform a phenomenological analysis of simplified models of light, feebly interacting particles (FIPs) that can provide a combined explanation of the anomalies in b → sl + l − transitions at LHCb and the anomalous magnetic moment of the muon. Different scenarios are categorised according to the explicit momentum dependence of the FIP coupling to the b−s and μ−μ vector currents and they are subject to several constraints from flavour and precision physics. We show that viable combined solutions to the muon g − 2 and flavour anomalies exist with the exchange of a vector FIP with mass larger than 4 GeV. Interestingly, the LHC has the potential to probe this region of the parameter space by increasing the precision of the Z → 4 μ cross-section measurement. Conversely, we find that solutions based on the exchange of a lighter vector, in the m V < 1 GeV range, are essentially excluded by a combination of B → K + invisible and W -decay precision bounds.