Drag force with different charges in STU background and AdS/CFT

In this paper we consider the drag force problem in the STU model. This problem and related topics were already studied in {\mathcal N}=4 SYM theory. Here we study the same problem in {\mathcal N}=2 supergravity theory with an R-charge black hole (the STU model). This paper extends our previous work (Sadeghi J and Pourhassan B 2008 J. High Energy Phys. JHEP12(2008)026; Sadeghi J, Setare M R, Pourhassan B and Hashmatian S 2009 Eur. Phys. J. C 61 527) by studying more general charge configurations and by taking into account the effect of a constant electromagnetic field and higher derivative corrections. We consider a single quark and a q \bar q pair in a three-charge non-extremal black hole background. First, by using the AdS/CFT correspondence, we obtain the drag force, the diffusion coefficient, the total energy and momentum, quasi-normal modes and the effect of higher derivative corrections for the single quark. Next we calculate the drag force for a q \bar q pair which rotates around its center of mass. For the first time we study the motion of a rotating q \bar q pair in this background. We show that our results in the near-extremal limit and finite chemical potential agree with the energy loss of the moving quark which was calculated in the {\mathcal N}=4 SYM plasma.