DESY Theory Seminar

TeV Scale Thermal WIMPs: Unitarity and its Consequences

by Juri Smirnov (CP3 Odense)

Monday, March 25, 2019 from to (Europe/Berlin)
at Bldg. 2A ( SR2 )
We re-examine unitarity bounds on the annihilation cross section of thermal-WIMP dark matter. For high-mass pointlike dark matter, it is generic to form WIMP bound states, which, together with Sommerfeld enhancement, affects the relic abundance. We show that these effects lower the unitarity bound from. For composite dark matter, for which the unitarity limit on the radius was thought to be mass-independent, we show that the largest allowed mass is 1 PeV. In addition, we find important new effects for annihilation in the late universe. For example, while the production of high-energy light fermions in WIMP annihilation is normally suppressed by helicity, we show that bound-state formation changes this, due to weak- boson mediated decays. Coupled with rapidly improving experimental sensitivity to TeV-range gamma rays, cosmic rays, and neutrinos, this gives hope for a first attack on the thermal-WIMP mass range from the high-mass end.