Search for neutrinos from the Sun

Detection of the free neutrino: A Confirmation

In this talk I review the present status of neutrino masses and mixing and some of their implications for particle physics phenomenology.

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The Physics of Massive Neutrinos

MINOS+ is an extension of the MINOS long-baseline neutrino experiment. It makes measurements of the upgraded NuMI neutrino beam at two detectors: the Near Detector, 1 km from the beam at Fermilab, Illinois and the Far Detector, 735 km from the beam in the Soudan Mine, Minnesota. A comparison of the neutrino energy spectra in these two detectors is made in order to investigate the effect of neutrino oscillations. This thesis documents the first MINOS+ beam νµ disappearance analysis. The data are combined with those from the MINOS beam disappearance, atmospheric νµ disappearance and beam νe appearance analyses, as well as additional atmospheric data taken after the MINOS shutdown, in order to estimate the parameters of the three- flavour neutrino oscillation model. The 68% confidence intervals on the atmospheric mixing angle obtained from this combined analysis are ∆m2 32 = 2.45+0.08 −0.11 × 10−3 eV2 and ∆m2 32 = 2.42+0.09 −0.11 × 10−3 eV2 , assuming normal and inverted neutrino mass hierarchy respectively. In addition, a measurement of the time of flight of the neutrino beam between the Near and Far Detector is described. The analysis is performed using data from the two detectors, along with a beam monitor at NuMI, various timers and long-distance synchronisation systems. This results in the most precise measurement of the flighttime of a neutrino beam ever made. The speed of the beam is calculated to be (v − c)/c = (1.0 ± 1.1) × 10−6 , consistent with v = c.

Three flavour neutrino oscillations in MINOS

Sterile antineutrino search with the MINOS and MINOS+ experiment

MINOS is a long baseline neutrino oscillation experiment. It measures the flux from the predominately muon neutrino NuMI beam first 1 km from beam start and then again 735 km later using a pair of steel scintillator tracking calorimeters. The comparison of measured neutrino energy spectra at our Far Detector with the prediction based on our Near Detector measurement allows for a measurement of the parameters which define neutrino oscillations. This thesis will describe the most recent measurement of muon neutrino disappearance in the NuMI muon neutrino beam using the MINOS experiment. \\\\ The general method of a disappearance analysis at the MINOS experiment will be outlined, the selection of events, extrapolation between detectors, and fitting the data to the atmospheric mixing parameters. An analysis of the full MINOS Forward Horn Current charged current muon neutrino interactions sample is detailed, with a best fit to the atmospheric mixing parameters in a two flavour approximation of $\Delta |m^2_{atm}| = 2.42\times10^{-3}~\mathrm{eV}^2$ and $\sin^2(2\theta_{23}) = 0.936$. The change to a three flavor analysis with matter effects from a simple two flavour approximation is described, with a very slight preference of $-2\Delta \log(L)=0.01$ for the inverted hiearchy found. A study of the NuMI beam is also shown, with potential locations for new oscillation experiments in the NuMI beam discussed.

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Alexander Radovic

Papers

Measuring the disappearance of muon neutrinos with the MINOS detectors