Excited(70,L+)baryons in a relativistic quark model

0 in a relativistic quark model

∗)l̄l in a relativistic quark model

We study the exclusive rare decay B → K(K∗)l̄l with special emphasis on the cascade decay B → K∗(→ Kπ)l̄l. We derive a four-fold angular decay distribution for this process in terms of helicity amplitudes including lepton mass effects. The four-fold angular decay distribution allows to define a number of physical observables which are amenable to measurement. We calculate the relevant form factor...

Isgur-wise Function in Relativistic Quark Model

Hadronic matrix elements are expressed in the framework of BS formalism, and in the limit of heavy quark mass mQ → ∞, we find that all form factors in processes of B → D weak transition can be incorporated into a single universal Isgur-Wise (I −W ) function ξ(v · v′), which was first discovered by Isgur and Wise in heavy quark effective theory (HQET). By introducing a phenomenological interacti...

Scalar Mesons in a Relativistic Quark Model with Instanton - Induced

In a relativistic quark model with linear confinement and an instanton-induced interaction which solves the η-η ′ puzzle, scalar mesons are found as almost pure SU(3) flavor states. This suggests a new interpretation of the scalar nonet: We propose that the recently discovered f 0 (1500) is not a glue-ball but the scalar (mainly)–octet meson for which the K ¯ K decay mode is suppressed. The mai...

Baryon Current Matrix Elements in a Relativistic Quark Model

Current matrix elements and observables for electro-and photo-excitation of baryons from the nucleon are studied in a light-front framework. Relativistic effects are examined by comparison to a nonrelativistic model and can typically be of order 20-25%, but can be larger for certain matrix elements, such as radial transitions conventionally used to describe the Roper resonance. A systematic stu...