We searched for a sidereal modulation in the rate of neutrinos produced by the NuMI beam and observed by the MINOS far detector. The detection of such harmonic signals could be a signature of ...neutrino–antineutrino mixing due to Lorentz and CPT violation as described by the Standard-Model Extension framework. We found no evidence for these sidereal signals and we placed limits on the coefficients in this theory describing the effect. This is the first report of limits on these neutrino–antineutrino mixing coefficients.
Observed since the 1950s, the seasonal effect on underground muons is a well studied phenomenon. The interaction height of incident cosmic rays changes as the temperature of the atmosphere changes, ...which affects the production height of mesons (mostly pions and kaons). The decay of these mesons produces muons that can be detected underground. The production of muons is dominated by pion decay, and previous work did not include the effect of kaons. In this work, the methods of Barrett and MACRO are extended to include the effect of kaons. These efforts give rise to a new method to measure the atmospheric
K
/
π
ratio at energies beyond the reach of current fixed target experiments. These methods were applied to data from the MINOS far detector. A method is developed for making these measurements at other underground detectors, including OPERA, Super-K, IceCube, Baksan and the MINOS near detector.
This investigation presents a new experimental determination of the reflectivity of 128 nm scintillation photons off stainless steel. The experiment took place in the TallBo dewar facility at ...Fermilab. The data were obtained using a detector that is sensitive to photons falling on its front face but is insensitive to photons falling on its back face or its sides. By comparing the ratio of photons per track from tracks that illuminate the front face of the detector to those that cross the back side with a simulation of the experiment where the reflectivity can be varied, a value of the reflectivity was determined. The reflectivity for the SA-240-304L stainless steel alloy off which the scintillation photons reflect in the TallBo dewar as found by this experiment is R = 0.674 +/- 0.038. The experiment is not sensitive to the differences between specular and diffuse reflections.
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