Heavy quark effective theory for mesons

Here an interest has been taken in the mesons with one heavy quarks and one light anti-quark out of up, down or strange quark. Such systems are of much interest because in such systems we encounter new symmetries which are not present even in the original theory (QCD). Such symmetries have been exploited to formulate a theory that describes the low energy interactions among the heavy mesons. The masses of even and odd parity charmed mesons have been studied within the framework of heavy quark effective theory and the chiral perturbation theory