Axino abundances in high-scale supersymmetry

Publication date: Available online 15 November 2018Source: Physics of the Dark UniverseAuthor(s): Ki-Young Choi, Hyun Min LeeAbstractWe consider the thermal production of axino dark matter in high-scale supersymmetry where all the superparticles except the axino are heavier than the maximum and reheating temperatures. In this case, the axinos are produced dominantly in pairs from the scattering of SM particles in thermal plasma in the early Universe after inflation. We find that the thermal averaged scattering cross section for the axino pair production is given by 〈σv〉∝T4 in Kim-Shifman-Vainstein-Zakharov (KSVZ) axion model, while it does not depend on the temperature in Dine-Fischler-Srednicki-Zhitnitski (DFSZ) axion model. As a result, the axinos produced during the early matter domination is diluted by the entropy production, so the axino abundance is determined mainly by the reheating temperature, unlike the case with gravitino dark matter. We show that the axino pair production in DFSZ model opens up new parameter space for axino dark matter, due to non-decoupled Higgsino interactions at tree level.

Source: Physics of the Dark Universe - November 16, 2018 Category: Physics Source Type: research