Kinetic Misalignment Mechanism. (arXiv:1910.14152v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Co_R/0/1/0/all/0/1">Raymond T. Co</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Hall_L/0/1/0/all/0/1">Lawrence J. Hall</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Harigaya_K/0/1/0/all/0/1">Keisuke Harigaya</a>
In the conventional misalignment mechanism, the axion field has a constant
initial field value in the early universe and later begins to oscillate. We
present an alternative scenario where the axion field has a nonzero initial
velocity, allowing an axion decay constant much below the conventional
prediction from axion dark matter. This axion velocity can be generated from
explicit breaking of the axion shift symmetry in the early universe, which may
occur as this symmetry is approximate.
In the conventional misalignment mechanism, the axion field has a constant
initial field value in the early universe and later begins to oscillate. We
present an alternative scenario where the axion field has a nonzero initial
velocity, allowing an axion decay constant much below the conventional
prediction from axion dark matter. This axion velocity can be generated from
explicit breaking of the axion shift symmetry in the early universe, which may
occur as this symmetry is approximate.
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