  The current noise in a quantum dot coupled to two leads is investigated in
the Kondo regime with and without the influence of magnetic fields by employing
a finite-$U$ slave-boson mean field theory to calculate the current-current
correlation function at zero temperature. The numerical results show that,
depending on the energy level of the QD the Coulomb interactin may reduce or
enhance the zero-frequency shot noise power spectrum in comparison with that
without Coulomb interaction. But the Fano factor is always reduced
significantly due to the Kondo-correlation effect, and the most pronounced
suppression appears at the electron-hole symmetry case $2\epsilon_d+U=0$. In
addition, the application of a magnetic field enhance the Fano factor of the
shot noise at small external voltage, which is attributed to the reduction of
the Kondo-enhanced density-of-state and transmission probability in a quantum
dot.
