TY - JOUR
T1 - Dark matter in axion landscape
AU - Daido, Ryuji
AU - Kobayashi, Takeshi
AU - Takahashi, Fuminobu
N1 - Funding Information:
T.K. would like to thank the Particle Theory and Cosmology Group of Tohoku University for hospitality during the initiation of this work. This work is supported by Tohoku University Division for Interdisciplinary Advanced Research and Education (R.D.), INFN INDARK PD51 grant (T.K.), MEXT KAKENHI Grant Numbers 15H05889 and 15K21733 (F.T.), JSPS KAKENHI Grant Numbers 26247042 and 26287039 (F.T.), and World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan (F.T.).
Publisher Copyright:
© 2016 The Authors
PY - 2017/2/10
Y1 - 2017/2/10
N2 - If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density. In particular we focus on a case in which two (or more) shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.
AB - If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density. In particular we focus on a case in which two (or more) shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.
UR - http://www.scopus.com/inward/record.url?scp=85007271210&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85007271210&partnerID=8YFLogxK
U2 - 10.1016/j.physletb.2016.12.034
DO - 10.1016/j.physletb.2016.12.034
M3 - Article
AN - SCOPUS:85007271210
VL - 765
SP - 293
EP - 299
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
ER -