Axino dark matter in light of an anomalous X-ray line

Axino as the superpartner of axion that solves the strong CP problem can be a good candidate of dark matter. Inspired by the 3.5 keV X-ray line signal found to be originated from galaxy clusters and Andromeda galaxy, we study axino models with R-parity violations, and point out that axino dark matter with trilinear R-parity violations is an attractive scenario that reproduces the X-ray line. The Peccei-Quinn scale is required to be f(a) similar to (10(9)-10(11)) GeV for trilinear R-parity violating couplings lambda similar to (sic)(10(-3)-10(-1)) in order to explain the line signal. Moreover, the right-handed stau is predicted to be light, i.e. similar to (sic) (100) GeV, and thus can be looked for at the LHC. Cosmological aspects of the model are also discussed in this study.