ALPS seminar

MadMax: A new QCD dark matter axion search using a dielectric haloscope

by Bela Majorovits (MPI fuer Physik)

Monday, July 11, 2016 from to (Europe/Berlin)
at DESY Hamburg ( SemR 2 )
Description
Axions are hypothetical low-mass bosons which are predicted to exist by
the Peccei-Quinn mechanism that can explain the absence of CP-violating
effects in quantum chromodynamics (QCD). Axions could also provide the
cold dark matter of the universe and as such are among the few particle
candidates that solve simultaneously two major problems of nature. All
existing experimental efforts focus on a range of axion masses below 20
ueV which is motivated by the traditional re-alignment mechanism of the
axion field. If the Peccei-Quinn symmetry was restored after inflation,
decaying topological defects could lead to an axion population providing
all of the cold dark matter with an axion mass in the range of 100–300
ueV. We present a new project based on the idea of axion photon conversion
at the transition between two media with different dielectric constants.
With a homogeneous magnetic field at such a transition layer, coherent
photon production in the microwave regime could be generated by the
hypothetical dark matter axion field. A significant boost in photon
conversion can be achieved when using several layers with alternating
dielectric constants. The additional surfaces are forming coupled resonant
cavities and could enhance the axion-photon conversion rate significantly.
A resonator with a boost factor of ~10^4 within a magnetic field of order
10T could be enough to achieve an axion-photon conversion rate within a
reasonable volume to be unambiguously detected with state of the art
radiometer technology within a reasonable time per frequency band. The
experimental idea and the proposed design for an experiment will be
discussed in some detail. First results from measurements of the expected
preamplifier noise and the microwave radiation transmission behavior of a
prototype resonant dielectric cavity will be discussed. The prospects for
reaching a sensitivity enough to cover the parameter space predicted for
QCD dark matter axions with mass in the range 100-300 ueV will be
presented.