N=4 superconformal mechanics from the su(2) perspective

The issue of constructing an N=4 superconformal mechanics in one dimension is reconsidered with a special emphasis put on the realizations of the su(2)-subalgebra in the full su(1,1|2)-superalgebra. New dynamical realizations of su(1,1|2) are constructed which describe an interaction of the (0,4,4)-supermultiplet with either the (1,4,3)-, or (3,4,1)-, or (4,4,0)-supermultiplet. A relation of the N=4 superconformal mechanics with massive superparticles propagating near the black hole horizons is discussed. Background geometry associated with the model based on the (4,4,0)-supermultiplet is identified with the near horizon limit of the d=5, N=2 supergravity interacting with one vector multiplet.