Speaker
Alessandro Strumia
(Pisa U & INFN & CERN)
Description
We explore the possibility that Dark Matter is the lightest hadron made of two stable color octet Dirac fermions $\Q$. The cosmological DM abundance is reproduced for $M_\Q\approx 9.5 \TeV$, compatibly with direct searches (the Rayleigh cross section, suppressed by $1/M_\Q^6$, is close to present bounds), indirect searches (enhanced by $\Q\Q+\bar\Q\bar\Q\to \Q\bar\Q+\Q\bar\Q$ recombination), and with collider searches (where $\Q$ manifests as tracks, pair produced via QCD). Hybrid hadrons, made of $\Q$ and of SM quarks and gluons, have large QCD cross sections, and do not reach underground detectors. Their cosmological abundance is $10^5$ times smaller than DM, such that their unusual signals seem compatible with bounds. Those in the Earth and stars sank to their centers; the Earth crust and meteorites later accumulate a secondary abundance, although their present abundance depends on nuclear and geological properties that we cannot compute from first principles.
