2026-04-13T04:03:03Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1233402025-12-05T16:54:07Zcom_2072_1057col_2072_478823col_2072_478904col_2072_478917

00925njm 22002777a 4500 dc Di Luzio, Luca author Mescia, Federico author Nardi, Enrico author 2018-07-03T13:45:31Z 2018-07-03T13:45:31Z 2017-10-03 2018-07-03T13:45:31Z We discuss phenomenological criteria for defining "axion windows," namely regions in the parameter space of the axion-photon coupling where realistic models live. Currently, the boundaries of this region depend on somewhat arbitrary criteria, and it would be highly desirable to specify them in terms of precise phenomenological requirements. We first focus on hadronic axion models within post-inflationary scenarios, in which the initial abundance of the new vectorlike quarks Q is thermal. We classify their representations R Q by requiring that (i) the Q are sufficiently short lived to avoid issues with long-lived strongly interacting relics, (ii) the theory remains weakly coupled up to the Planck scale. The more general case of multiple R Q is also studied, and the absolute upper and lower bounds on the axion-photon coupling as a function of the axion mass is identified. Pre-inflationary scenarios in which the axion decay constant remains bounded as f a ≤ 5 × 10 11     GeV allow for axion-photon couplings only about 20% larger. Realistic Dine-Fischler-Srednicki-Zhitnitsky type of axion models also remain encompassed within the hadronic axion window. Some mechanisms that can allow to enhance the axion-photon coupling to values sizeably above the preferred window are discussed. Partícules (Matèria) Particles Window for preferred axion models