TY  - JOUR
AU  - Huang, J. W.
AU  - Madden, A.
AU  - Racco, D.
AU  - Reig, M.
PY  - 2020
DA  - 2020//
TI  - Maximal axion misalignment from a minimal model
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 143
EP  - 39pp
VL  - 10
IS  - 10
PB  - Springer
KW  - Beyond Standard Model
KW  - Cosmology of Theories beyond the SM
AB  - The QCD axion is one of the best motivated dark matter candidates. The misalignment mechanism is well known to produce an abundance of the QCD axion consistent with dark matter for an axion decay constant of order 10(12) GeV. For a smaller decay constant, the QCD axion, with Peccei-Quinn symmetry broken during inflation, makes up only a fraction of dark matter unless the axion field starts oscillating very close to the top of its potential, in a scenario called "large-misalignment". In this scenario, QCD axion dark matter with a small axion decay constant is partially comprised of very dense structures. We present a simple dynamical model realising the large-misalignment mechanism. During inflation, the axion classically rolls down its potential approaching its minimum. After inflation, the Universe reheats to a high temperature and a modulus (real scalar field) changes the sign of its minimum dynamically, which changes the sign of the mass of a vector-like fermion charged under QCD. As a result, the minimum of the axion potential during inflation becomes the maximum of the potential after the Universe has cooled through the QCD phase transition and the axion starts oscillating. In this model, we can produce QCD axion dark matter with a decay constant as low as 6 x 10(9) GeV and an axion mass up to 1 meV. We also summarise the phenomenological implications of this mechanism for dark matter experiments and colliders.
SN  - 1029-8479
UR  - https://arxiv.org/abs/2006.07379
UR  - https://doi.org/10.1007/JHEP10(2020)143
DO  - 10.1007/JHEP10(2020)143
LA  - English
N1  - WOS:000586368800006
ID  - Huang_etal2020
ER  -