Thesis (Ph.D.) - Indiana University, Physics, 2015The NOvA experiment is a long-baseline neutrino oscillation experiment based out of Fermilab National Accelerator Laboratory that uses two liquid scintillator detectors, one at Fermilab (the "near" detector) and a second 14 kton detector in northern Minnesota (the "far" detector.) The primary physics goals of the NOvA experiment are to measure neutrino mixing parameters through both the $\nu_{\mu}$ disappearance and $\nu_{e}$ appearance channels using neutrinos from the newly upgraded NuMI beam line. The NOvA $\nu_{\mu}$ disappearance analysis can significantly improve the world's best measurement of $\sin^{2}\theta_{23}$. This analysis proceeds by using the measured $\nu_{\mu}$ charged-current energy spectrum in the near detector to predict the spectrum in the far detector, and comparing this to the measured spectrum to obtain a best fit for the oscillation parameters $\sin^{2}\theta_{23}$ and $\Delta m^{2}_{32}$. Since this fit is governed by the shape of the energy spectrum, the best fit will be maximized by obtaining the best possible energy resolution for the individual neutrino events. This dissertation describes an alternate $\nu_{\mu}$ disappearance analysis technique for the NOvA experiment, based on the idea that estimating the energy resolution of the individual events will allow them to be separated into different energy resolution samples in order to improve the final fit. This involves using an optimal tracker to reconstruct particle tracks and momenta, and multivariate methods for estimating the event energies and energy resolutions. The data used for this analysis was taken by the NOvA experiment from February 2014 to May 2015, representing approximately $3.52 \times 10^{20}$ protons on target from the NuMI beam. The best fit oscillation parameters obtained by this alternate technique are $|\Delta m^{2}_{32}| = 2.49^{+0.19}_{-0.17}$~$[\times 10^{-3} {\rm eV}^{2}]$ and $\sin^{2} \theta_{23} =$~$0.51 \pm 0.08$ which is consistent with the hypothesis of maximal mixing, and with the results from T2K and MINOS+ published in 2015.