  One of the confident predictions of QCD is that at sufficiently high
temperature and/or density, hadronic matter should undergo a thermodynamic
phase transition to a colour deconfined state of matter - popularly called the
Quark-Gluon Plasma (QGP). In low energy effective theories of Quantum
Chromodynamics (QCD), one usually talks of the chiral transition for which a
well defined order parameter exists. We investigate the dissociation of pions
and kaons in a medium of hot quark matter decsribed by the Nambu - Jona Lasinio
(NJL) model. The decay widths of pion and kaon are found to be large but finite
at temperature much higher than the critical temperature for the chiral (or
deconfinement) transition, the kaon decay width being much larger. Thus pions
and even kaons (with a lower density compared to pions) may coexist with quarks
and gluons at such high temperatures. On the basis of such premises, we
investigate the process of hadronization in quark-gluon plasma with special
emphasis on whether such processes shed any light on acceptable low energy
effective theories of QCD.
