arXiv subjects

Shashank Bhatnagar

Publications and source records attributed to Shashank Bhatnagar.

21 records · Page 2Linked to original sources

arXiv2009

Arranging Dirac covariants in hadronic Bethe-Salpeter wave functions for pseudoscalar meson decays

We have employed the framework of Bethe-Salpeter equation under covariant instantaneous ansatz to calculate leptonic decay constants of unequal mass pseudoscalar mesons like pi, K, D, Ds and B and radiative decay constants of neutral pseudoscalar mesons like pi and etac in two photon decays of these mesons. In the Dirac structure of hadronic BS wave function, the covariants are incorporated from their complete set in accordance with a recently proposed power counting rule, order-by-order in powers of inverse of meson mass. The decay constants are calculated with the incorporation of both Leading order (LO) and the Next-to-leading order (NLO) Dirac covariants. The contribution of both LO as well as NLO Dirac covariants are studied in detail in this paper. The results are found to improve dramatically and hence validating the power counting rule which also provides a practical means of incorporating Dirac covariants in the BS wave function for a hadron.

hep-ph↗

arXiv2007

Decay Constants of Pseudoscalar Mesons in Bethe-Salpeter Framework with Generalized Structure of Hadron-Quark Vertex

We employ the framework of Bethe-Salpeter equation under Covariant Instantaneous Ansatz to study the leptonic decays of pseudoscalar mesons. The Dirac structure of hadron-quark vertex function $Γ$ is generalized to include various Dirac covariants besides $γ_5 $ from their complete set. The covariants are incorporated in accordance with a power counting rule, order by order in powers of the inverse of the meson mass. The decay constants are calculated with the incorporation of leading order covariants. Most of the results are dramatically improved.

hep-ph↗

arXiv2006

Generalized structure of hadron-quark vertex function in Bethe-Salpeter framework: Applications to leptonic decays of V-mesons

We employ the framework of Bethe-Salpeter equation under Covariant Instantaneous Ansatz (CIA) to study the leptonic decays of vector mesons. The structure of hadron-quark vertex function Gamma is generalized to include various Dirac covariants (other than i gamma dot epsilon) from their complete set. They are incorporated in accordance with a naive power counting rule order by order in powers of the inverse of the meson mass. The decay constants for rho omega and phi mesons are calculated with the incorporation of leading order covariants.

hep-ph↗