We study heavy light mesons in a QCD inspired quark model with the Cornell potential [Formula: see text]. Here we consider the linear term br as the parent and [Formula: see text], i.e. the Coloumbic part as the perturbation. The linear parent leads to Airy function as the unperturbed wave function. We then use the Dalgarno method of perturbation theory to obtain the total wave function corrected up to first order with Coulombic piece as the perturbation. With these wave functions, we study the Isgur–Wise function and calculate its slope and curvature.

This letter reports some improvement of the formalism and analysis of our very recent work [1] on the studies of Isgur-Wise function for heavy-light mesons following higher dimensional string inspired potential model.

Determination of wave function is very essential in the calculation of static and dynamic properties like masses and decay constants of pseudo scalar mesons and masses of vector mesons . We useDalgarno's perturbation theory and Variationally Improved Perturbation Theory (VIPT) to solve the Schroedinger equation in a QCD inspired potential model with the Cornell potential which consists of coulomb and linear potential. We use both the options like Columbic parent firstly and then linear parent while using the VIPT method. Comparison of both these methods and also with experimental results are done in the calculation of masses and decay constants.

We have recently reported the calculation of slope and curvature of Isgur-Wise function based on Variationally Improved Perturbation Theory (VIPT) in a QCD inspired potential model. In that work, Coulombic potential was taken as the parent while the linear one as the perturbation.In this work, we choose the linear one as the parent with Coulombic one as the perturbation and see the consequences.

The quantum chromodynamics-inspired potential model pursued by us earlier has been recently modified to incorporate an additional factor 'c' in the linear cum Coulomb potential. While it felicitates the inclusion of standard confinement parameter b = 0.183 GeV 2 unlike in previous work, it still falls short of explaining the Isgur-Wise function for the B mesons without ad hoc adjustment of the strong coupling constant. In this work, we determine the factor 'c' from the experimental values of decay constants and masses and show that the reality constraint on 'c' yields bounds on the strong coupling constant as well as on slope and curvature of Isgur-Wise function allowing more flexibility to the model.