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Seminars & Lectures

* TITLE

Axion production from topological defects

* SPEAKERS

Name	Affiliation	E-mail
Ken\'ichi Saikawa	Tokyo University

* HOST(Applicant)

Name	Affiliation	E-mail
Ki-Young Choi	APCTP

* DATE / TIME

2013-01-24, 11 am, 503 Conference room

* ABSTRACT

Axion is a hypothetical particle introduced as a solution of the strong CP problem of quantum chromodynamics. Due to the weakness of the coupling with ordinary matters, the axion is regarded as a viable candidate of dark matter of the universe. However, there is a theoretical uncertainty on the determination of the relic abundance of dark matter axions. This uncertainty comes from a poor understanding of the production mechanism due to the decay of topological defects such as strings and domain walls. In order to remove this uncertainty, we analyze the spectrum of axions radiated from networks of topological defects by performing field-theoretic lattice simulations. The results of numerical study revealed that axions produced by the defects give significant contributions to the relic cold dark matter abundance, which gives more severe constraints on axion models.

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