Theory: Deviations from Vanilla Axions by Small Size Instantons and Effects on PQ Symmetries from New U(1)' Gauge Symmetry Models
by
Felix Yu(Mainz U)
→
Europe/Berlin
SR2
SR2
Description
In the first part, we construct a new framework to calculate the enhancement of axion masses and concomitant effects on axion-meson mixing arising from small size instantons (SSIs), which originate in models featuring an extended color gauge symmetry. The framework is based on an explicit evaluation of ‘t Hooft determinantal operators that partition into instanton amplitudes, affording a more precise determination of the axion-diphoton coupling than previous results. We demonstrate that axions solving the strong CP problem can have electroweak scale masses and higher, driven by SSI effects. Such collider axions are prime targets for resonance searches at the Large Hadron Collider and afford a unique anchor for motivating extended color symmetries. In the second part, we explore the effective theory of an axion in a gauged baryon number symmetry extension of the Standard Model (SM), where the axion is realized from a Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) model construction. Integrating out the anomalons realizes a pattern of effective Wilson coefficients reflecting the factorization between the anomalous Peccei-Quinn and gauged baryon number symmetries. We construct and analyze the chiral transformation invariance of the axion effective theory, accounting for possible flavor-violating axion couplings. We calculate and study the unique phenomenology of the axion and Z′Z′ boson, and we present the current collider limits on these particles in the {mZ′,gB}, {ma,Gaγγ}, and {ma,fa−1} planes.
