Atmospheric neutrino induced muons in the MINOS Far Detector

The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment. The MINOS Far Detector, located in the Soudan Underground Laboratory in Soudan MN, has been collecting data since August 2003. The scope of this dissertation involves identifying the atmospheric neutrino induced muons that are created by the neutrinos interacting with the rock surrounding the detector cavern, performing a neutrino oscillation search by measuring the oscillation parameter values of Dm223 and sin22theta23, and searching for CPT violation by measuring the charge ratio for the atmospheric neutrino induced muons.; A series of selection cuts are applied to the data set in order to extract the neutrino induced muons. As a result, a total of 148 candidate events are selected. The oscillation search is performed by measuring the low to high muon momentum ratio in the data sample and comparing it to the same ratio in the Monte Carlo simulation in the absence of neutrino oscillation. The measured double ratios for the "all events" (A) and high resolution (HR) samples are RA=Rdatalow/high RMClow/high=0.60 +0.11-0.10stat +/-0.08syst and RHR=Rdatalow/high RMClow/high=0.58 +0.14-0.11stat +/-0.05syst, respectively. Both event samples show a significant deviation from unity giving a strong indication of neutrino oscillation.; A combined momentum and zenith angle oscillation fit is performed using the method of maximum lob likelihood with a grid search in the parameter space of Deltam2 and sin22theta. The best fit point for both event samples occurs at Dm223 = 1.3 x 10-3 eV2, and sin22theta23 = 1. This result is compatible with previous measurements from the Super Kamiokande experiment and Soudan 2 experiments.; The MINOS Far Detector is the first underground neutrino detector to be able to distinguish the charge of the muons. The measured charge is used to test the rate of the neutrino to the anti-neutrino oscillations by measuring the neutrino induced muon charge ratio. Using the high resolution sample, the mu+ to mu- double charge ratio has been determined to be RCPT=Rdatam -/m+RMC m-/m+=0.9 0+0.24-0.18stat +/-0.09syst. With the uncertainties added in quadrature, the CPT double ratio is consistent with unity showing no indication for CPT violation.