Collider constraints on light pseudoscalars

Abstract

We investigate the bounds on light pseudoscalars that arise from a variety of collider searches. Special attention is thereby devoted to the mass regions $[3,5]\mathrm{GeV}$ and $[9,11]\mathrm{GeV}$, in which a meaningful theoretical description has to include estimates of non-perturbative effects such as the mixing of the pseudoscalar with QCD bound states. A compendium of formulas that allows to deal with the relevant corrections is provided. It should prove useful for the interpretation of future LHC searches for light CP-odd spin-0 states.

Comments: 17 pages, 3 figures, 2 tables; v3: new draft includes the constraints from CMS-PAS-HIG-17-024 and CMS-PAS-HIG-17-029; a similar version has been published in JHEP. also contained in arXiv:1803.10379