Optimization of Neutrino Oscillation Parameters using Differential
  Evolution
  We combine Differential Evolution, a new technique, with the traditional grid
based method for optimization of solar neutrino oscillation parameters $\Delta
m^2$ and $\tan^{2}\theta$ for the case of two neutrinos. The Differential
Evolution is a population based stochastic algorithm for optimization of real
valued non-linear non-differentiable objective functions that has become very
popular during the last decade. We calculate well known chi-square ($\chi^2$)
function for neutrino oscillations for a grid of the parameters using total
event rates of chlorine (Homestake), Gallax+GNO, SAGE, Superkamiokande and SNO
detectors and theoretically calculated event rates. We find minimum $\chi^2$
values in different regions of the parameter space. We explore regions around
these minima using Differential Evolution for the fine tuning of the parameters
allowing even those values of the parameters which do not lie on any grid. We
note as much as 4 times decrease in $\chi^2$ value in the SMA region and even
better goodness-of-fit as compared to our grid-based results. All this
indicates a way out of the impasse faced due to CPU limitations of the larger
grid method.
