Connection between a possible fifth force and the direct detection of dark matter.

If there were a fifth force in the dark sector and dark matter (DM) particles interacted nongravitationally with ordinary matter, quantum corrections generically would lead to a fifth force in the visible sector. We show how the strong experimental limits on fifth forces in the visible sector produce bounds on the cross section for DM detection and the strength of the fifth force in the dark sector. For a fifth force comparable in strength to gravity, the spin-independent direct detection cross section must typically be less, similar10;{-55} cm;{2}. The anomalous acceleration of ordinary matter falling towards dark matter would also be constrained: eta_{OM-DM} less, similar10;{-8}.

Strong CP problem with 10(32) standard model copies.

We show that a recently proposed solution to the hierarchy problem simultaneously solves the strong CP problem, without requiring an axion or any further new physics. Consistency of black hole physics implies a nontrivial relation between the number of particle species and particle masses, so that with approximately 10(32) copies of the standard model, the TeV scale is naturally explained. At the same time, as shown here, this setup predicts a typical expected value of the strong-CP parameter in QCD of theta approximately 10(-9). This strongly motivates a more sensitive measurement of the neutron electric dipole moment.

Dark matter and the baryon asymmetry of the universe.

We present a mechanism to generate the baryon asymmetry of the Universe which preserves the net baryon number created in the big bang. If dark matter particles carry baryon number Bx, and sigmaxannih