  The mass spectra of $D$ meson states are calculated in the framework of a
relativistic independent quark model. For the present study, we have used the
martin like potential for the quark confinement. Our predicted states in
S-wave, $2\ ^3S_1$ (2605.86 MeV) and $2\ ^1S_0$ (2521.72 MeV) are in very good
agreement with experimental result of $2608\pm{2.4}\pm{2.5}$ MeV and
$2539.4\pm{4.5}\pm{6.8}$ MeV respectively reported by BABAR Collaboration. The
calculated P-wave $D$ meson states, $1^3P_2$ (2468.22 MeV), $1^3P_1$ (2404.94
MeV), $1^3P_0$ (2315.24 MeV) and $1^1P_1$ (2367.94 MeV) are in close agreement
with experimental average (Particle Data Group) values of $2462.6 \pm 0.7 $
MeV, $2427 \pm 26 \pm 25$ MeV, $2318 \pm 29 $ MeV and $2421.3 \pm 0.6 $ MeV
respectively. The pseudoscalar decay constant ($f_P$= 202.57 MeV) of $D$ meson
obtained using this relativistic formalism is in very good agreement with the
experiment as well as with the lattice and other available theoretical
predictions. The Cabibbo favoured hadronic decay branching ratios,
BR$(D^0\rightarrow K^- \pi^+)$ as $3.835 \%$ and BR $(D^0\rightarrow K^+
\pi^-)$ as $1.069 \times 10^{-4} $ are also in very good agreement with the
respective experimental values of $ 3.91 \pm 0.08\%$ and $(1.48\pm 0.07) \times
10^{-4}$ reported by CLEO Collaboration. Our predicted results in leptonic
decay widths of $D$ meson are also in better accord with experiment as well as
other theoretical results. The mixing parameters of $D^0 - \bar{D}^0$
oscillation, $x_q$ (5.14 $\times 10^{-3}$), $y_q$ (6.02 $\times 10^{-3}$) and
$R_M$ (3.13 $\times 10^{-5}$) are in very good agreement with BaBar and Belle
Collaboration results.
