Linear sigma dark matter
Dan Kondo, Robert McGehee, Tom Melia, Hitoshi Murayama
Abstract
A bstract We present a model of self-interacting dark matter based on QCD-like theories and inspired by the proximity of a 0 (980 ± 20) to the $$ K\overline{K} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>K</mml:mi> <mml:mover> <mml:mi>K</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> (990) threshold. Dark matter is comprised of dark pions which self-scatter via the σ resonance close to the ππ threshold. While the linear sigma model serves as a qualitative guide, a fully unitary description of the scattering in the strongly coupled regime is given by effective range theory. The introduction of a kinetically mixed dark photon allows the dark pion to either freeze-out or -in. We study the viable parameter space which explains the observed relic abundance while evading all current constraints. Searches for dark matter self interactions at different scales, (in)direct detection signals, and (in)visibly-decaying dark photons will test this model in the near future.