Seth Hoedl
A Torsion Pendulum Based Axion Search.
Despite two decades of experimental effort, the elusive axion has yet
to be found. Nevertheless, for possible axion masses between
1 mu-eV and 10 meV, it remains a well motivated solution to the
strong CP problem, and a promising dark matter candidate. Current
searches use an hypothetical axion-two-photon coupling to probe for
axions that could be generated in the sun and for axions that could be
remnants from the big-bang. Using techniques inspired by torsion
pendulum based tests of gravity, we have constructed a new torsion
pendulum experiment that looks for a macroscopic parity and time
violating force mediated by virtual axions. For an axion mass of
1 meV, we have improved the limit on this force by ten orders of
magnitude. In addition, we have demonstrated that one can operate a
torsion pendulum in a strong magnetic field, and thus, have opened
another path to look for very heavy axions.