TY - JOUR
T1 - Solving the tension between high-scale inflation and axion isocurvature perturbations
AU - Higaki, Tetsutaro
AU - Jeong, Kwang Sik
AU - Takahashi, Fuminobu
N1 - Funding Information:
This work was supported by Grant-in-Aid for Scientific Research on Innovative Areas (No. 24111702 , No. 21111006 , and No. 23104008 ) [F.T.], Scientific Research (A) (No. 22244030 and No. 21244033 ) [F.T.], and JSPS Grant-in-Aid for Young Scientists (B) (No. 24740135 [F.T.] and No. 25800169 [T.H.]), and Inoue Foundation for Science [F.T.]. This work was also supported by World Premier International Center Initiative (WPI Program), MEXT , Japan [F.T.].
PY - 2014/6/27
Y1 - 2014/6/27
N2 - The BICEP2 experiment determined the Hubble parameter during inflation to be about 1014 GeV. Such high inflation scale is in tension with the QCD axion dark matter if the Peccei-Quinn (PQ) symmetry remains broken during and after inflation, because too large axion isocurvature perturbations would be generated. The axion isocurvature perturbations can be suppressed if the axion acquires a sufficiently heavy mass during inflation. We show that this is realized if the PQ symmetry is explicitly broken down to a discrete symmetry and if the breaking is enhanced during inflation. We also show that, even when the PQ symmetry becomes spontaneously broken after inflation, such a temporarily enhanced PQ symmetry breaking relaxes the constraint on the axion decay constant.
AB - The BICEP2 experiment determined the Hubble parameter during inflation to be about 1014 GeV. Such high inflation scale is in tension with the QCD axion dark matter if the Peccei-Quinn (PQ) symmetry remains broken during and after inflation, because too large axion isocurvature perturbations would be generated. The axion isocurvature perturbations can be suppressed if the axion acquires a sufficiently heavy mass during inflation. We show that this is realized if the PQ symmetry is explicitly broken down to a discrete symmetry and if the breaking is enhanced during inflation. We also show that, even when the PQ symmetry becomes spontaneously broken after inflation, such a temporarily enhanced PQ symmetry breaking relaxes the constraint on the axion decay constant.
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U2 - 10.1016/j.physletb.2014.05.014
DO - 10.1016/j.physletb.2014.05.014
M3 - Article
AN - SCOPUS:84901012583
SN - 0370-2693
VL - 734
SP - 21
EP - 26
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
ER -