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Georg Raffelt, Max-Planck-Institut für Physik, München, Germany<br />
<strong>Axion</strong> Physics in a Nut Shell<br />
PONT d‘Avignon, 21-25 April 2008, Avignon, France<br />
Particle-Physics Physics Motivation<br />
CP conservation in QCD by<br />
Peccei-Quinn mechanism<br />
→ <strong>Axion</strong>s a ~ π 0<br />
m π f π ≈ m a f a<br />
For f a ≫ f π axions are “invisible”<br />
and very light<br />
a<br />
γ<br />
γ<br />
Solar and Stellar <strong>Axion</strong>s<br />
<strong>Axion</strong>s thermally produced in stars,<br />
e.g. by Primakoff production<br />
γ<br />
a<br />
• Limits from avoiding excessive<br />
energy drain<br />
• Search for solar axions (CAST, Sumico)<br />
Cosmology<br />
Search for <strong>Axion</strong> Dark Matter<br />
In spite of small mass, axions<br />
are born non-relativistically<br />
(“non-thermal relics”)<br />
N<br />
Microwave resonator<br />
(1 GHz = 4 μeV)<br />
→ “Cold dark matter”<br />
candidate<br />
m a ~ 1-10001<br />
1000 μeV<br />
Cosmic<br />
String<br />
S<br />
a<br />
Primakoff<br />
conversion<br />
B ext<br />
γ
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