BPS Spectra of dyons in four-dimensional N=2 supersymmetric theories

Analysing the kinematics and monodromies around singularities in quantum mo duli space of four-dimensional N = 2 supersymmetric theory without as well as, with hypermultiplets, spectra of BPS states have been obtained separate ly in weak and strong coupling regions. It has been shown that in the absen ce of hypermultiplets, the weak coupling spectrum contains all dyons with i ntegral electric charges and unit magnetic charge while the strong coupling spectrum consists of only the particles responsible for the monodromies at singularities. Demonstrating electric-magnetic-flavour duality in the pres ence of supermultiplets with non-zero bare masses, it has been shown that i n the presence of single flavour, coulomb branch of moduli space exhibits Z (3)-symmetry with dyonic states of single unit of magnetic charge existing in the weak and strong coupling regions. It has also been shown that the st rong coupling spectrum, in presence of two flavours, consists of one Z(2)-p air and that, in presence of three flavours, it consists of dyons with one and two units of magnetic charge.