JC April - Arturo de Girogi

Tuesday 28 Apr 2026, 15:00 → 16:00 Europe/Rome

Axions and axion-like particles generically appear in extensions of the Standard Model. While many searches assume only a single axion species, there may exist a whole spectrum of multiple such fields. We develop general formulas for axion-photon oscillations in the presence of multiple axions and analyze the implications for experimental searches, focussing on light-shining-through-a-wall experiments. We demonstrate that axion multiplicity can qualitatively alter observational signatures, particularly through coherence and interference effects. Multiple axions can not only enhance signals compared to single axion scenarios, but also suppress them. We show that variations of experimental parameters and searches allow identifying contributions of multiple axions and obtaining information about their properties.