Speaker
Description
There is rampant pessimism in the collder and dark matter communities
regarding the prospects for SUSY dark matter, but this is based on old
prejudices from the 20th century. A proper calculation of electroweak
finetuning reveals the LSP should be a light higgsino state which is
thermally underproduced. But solving the strong CP problem requires
a QCD axion, and the DFSZ model which requires two Higgs doublets
melds well with SUSY. In fact, SUSY and axions solve several problems
on each side: for instance, intrinsically SUSY discrete R-symmetries
which arise from string compactifications yield R-parity conservation and
allow PQ to emerge as an accidental, approximate global U(1) while
solving the SUSY mu problem where the PQ scale f_a then related to the
hidden sector SUSY breaking scale ~10^11 GeV, in the cosmological sweet spot.
Dark matter is then a mixture of DFSZ axions and higgsino-like WIMPs,
the latter with a diminished abundance: mainly axions.
The axion-photon coupling is quite diminished
due to the presence of higgsinos. The relic abundance requires eight-coupled
Boltzmann equations which account also for saxions and axinos in the
early universe. The effect of light stringy moduli (LSM)
fields is also addressed, and seems to require m(LSM)>~5 PeV to avoid
overproduction of higgsino-like WIMPs.
