Exclusive semileptonic decays of $D$ and $D_s$ mesons into orbitally and radially excited states of strange and light mesons

TL;DR

This paper provides a detailed relativistic quark model analysis of semileptonic decays of $D$ and $D_s$ mesons into excited strange and light mesons, calculating form factors and decay rates with relativistic effects.

Contribution

It introduces a comprehensive relativistic approach to compute form factors and decay rates for semileptonic $D$ and $D_s$ decays into excited mesons, including relativistic effects and wave function boosts.

Findings

Form factors are explicitly calculated across the entire kinematic range.

Theoretical decay rates show reasonable agreement with experimental data.

Relativistic effects significantly influence the decay dynamics.

Abstract

Semileptonic decays of $D$ and $D_s$ mesons into orbitally and radially excited strange and light mesons are studied in detail within the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The hadronic matrix elements of the weak current between meson states are calculated with the consistent account of relativistic effects including contributions of the intermediate negative energy states and boosts of the meson wave functions from the rest to moving reference frame. The invariant form factors that parameterize these matrix elements are obtained as the overlap integrals of the initial and final meson wave functions. Their dependence on the square of the transferred momentum $q^2$ is explicitly determined within the whole accessible kinematic range. A convenient analytical approximation for numerical values of form factors is given. These form factors and helicity formalism are employed for the calculation of the differential and total semileptonic decay rates of charm mesons into excited strange and light mesons. Different asymmetry and polarization parameters are also evaluated. The obtained results are compared with other theoretical calculations and available experimental data. Reasonable agreement with experimentally measured semileptonic decay branching fractions and upper bounds is obtained.