https://doi.org/10.1140/epjc/s10052-019-6587-9
Regular Article - Theoretical Physics
Axion-like particles at future colliders
1
Institute for Particle Physics Phenomenology, Ogden Centre for Fundamental Physics, Durham University, South Road, Durham, DH1 3LE, United Kingdom
2
PRISMA Cluster of Excellence, Mainz Institute for Theoretical Physics, Johannes Gutenberg University, 55099, Mainz, Germany
3
Department of Physics, LEPP, Cornell University, Ithaca, NY, 14853, USA
4
Theoretical Physics Department, CERN, 1211, Geneva, Switzerland
* e-mail: andrea.thamm@cern.ch
Received:
24
September
2018
Accepted:
10
January
2019
Published online:
28
January
2019
Axion-like particles (ALPs) are pseudo Nambu–Goldstone bosons of spontaneously broken global symmetries in high-energy extensions of the Standard Model (SM). This makes them a prime target for future experiments aiming to discover new physics which addresses some of the open questions of the SM. While future high-precision experiments can discover ALPs with masses well below the GeV scale, heavier ALPs can be searched for at future high-energy lepton and hadron colliders. We discuss the reach of the different proposed colliders, focusing on resonant ALP production, ALP production in the decay of heavy SM resonances, and associate ALP production with photons, Z bosons or Higgs bosons. We consider the leading effective operators mediating interactions between the ALP and SM particles and discuss search strategies for ALPs decaying promptly as well as ALPs with delayed decays. Projections for the high-luminosity run of the LHC and its high-energy upgrade, CLIC, the future 
ring-colliders CEPC and FCC-ee, the future pp colliders SPPC and FCC-hh, and for the MATHUSLA surface array are presented. We further discuss the constraining power of future measurements of electroweak precision parameters on the relevant ALP couplings.
© The Author(s), 2019
