The MINOS long-baseline experiment is using the NuMI neutrino beam to make precise measurements of neutrino flavor oscillations in the "atmospheric" neutrino sector. MINOS observes the $ν_μ$ disappearance oscillations seen in atmospheric neutrinos, tests possible disappearance to sterile $ν$ by measuring the neutral current flux, and extends our reach towards the so far unseen $θ_{13}$ by looking for $ν_e$ appearance in this $ν_μ$ beam. The magnetized MINOS detectors also allow tests of CPT conservation by discriminating between neutrinos and anti-neutrinos on an event-by-event basis. The intense, well-understood NuMI neutrino beam created at Fermilab is observed 735km away at the Soudan Mine in Northeast Minnesota. High-statistics studies of the neutrino interactions themselves and the cosmic rays seen by the MINOS detectors have also been made. MINOS started taking beam data in May of 2005 and is now nearing the end of it's five-year run. This paper reviews results published based on the first several years of data.
I describe two new searches for sterile neutrino oscillations from the MINOS and Daya Bay experiments. MINOS looked for evidence through muon neutrino disappearance with data collected from the NuMI neutrino beam. Daya Bay searched for evidence through electron antineutrino disappearance using data collected from nuclear reactors. I explain how the MINOS and Daya Bay searches were combined to produce constraints on the same phase space as LSND and MiniBooNE. Finally, I present the status of the sterile neutrino search using data from MINOS+.
Following a 7-year run with the MINOS experiment from 2005 to 2012, the MINOS+ long-baseline neutrino experiment started operations in September 2013. Utilizing the MINOS Near and Far Detectors at Fermilab and northern Minnesota, respectively, and measuring the new medium-energy NuMI neutrino beam over baseline of 735 km, MINOS+ has accumulated an exposure of $1.7\times 10^{20}$ protons-on-target. In this paper, we present preliminary results from the MINOS+run. In addition, we report on improved results from a three-neutrino flavor analysis of the full $14\times 10^{20}$ MINOS-era beam sample…
After a brief introduction to neutrino oscillations and a review of the world knowledge of neutrino oscillation parameters, we introduce two current neutrino oscillation experiments, MINOS and MiniBooNE. MINOS makes precise measurements of the oscillation parameters |Δm^{2}_{32}| and sin^{2} (2θ_{23}). MiniBooNE tests neutrino oscillations in the parameter region reported by the LSND experiment, which would require a new neutrino state. We review recent experimental results from both experiments and give an outlook on future measurements.
MINOS is a two-detector on-axis experiment based at Fermilab. The NuMI neutrino beam encounters the MINOS Near Detector 1 km downstream before travelling 734 km through the Earth's crust, to reach the Far Detector located at the Soudan Underground Laboratory in Northern Minnesota. By searching for oscillations driven by a large mass splitting, MINOS is sensitive to the existence of sterile neutrinos. This poster will present results of a search for sterile neutrinos that is sensitive to the parameter space suggested by LSND and MiniBooNE. Both charged current numu and neutral current neutrino …
The Main Injector Neutrino Oscillation Search (MINOS) experiment's Far Detector has been operational since July 2003, taking cosmic ray and atmospheric neutrino data from its location in the Soudan Mine Underground Lab. Numerous neutrino-induced muons have been observed. The detector's magnetic field allows the first determination by a large underground detector of muon charge and thus neutrino versus anti-neutrino on an event by event basis.
Using a NuMI beam exposure of 7.1 /times 10^20 protons-on-target, the MINOS long-baseline experiment has performed a search for active to sterile neutrino mixing over a distance of 735 km. Details of the analysis are provided, along with results from comparisons with standard three neutrino oscillations and fits to a 3+1 model including oscillations into one sterile neutrino. An outlook on the future sterile neutrino related contributions from MINOS and the proposed MINOS+ project is also presented.
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.
The MINOS experiment has used the world's most powerful neutrino beam to make precision neutrino oscillation measurements. By observing the disappearance of muon neutrinos, MINOS has made the world's most precise measurement of the larger neutrino mass splitting, and has measured the neutrino mixing angle $θ_{23}$. Using a dedicated antineutrino beam, MINOS has made the first direct precision measurements of the corresponding antineutrino parameters. A search for \nue and \nuebar appearance has enabled a measurement of the mixing angle $θ_{13}$. A measurement of the neutral-current interaction…
The MINOS experiment at Fermilab has released an updated result on muon disappearance based upon 2.5 x 10^20 protons on target. The experiment utilizes the intense source of muon neutrinos provided by the NuMI beam line. This note summarizes the systematic uncertainties in the experiment's knowledge of the flux and energy spectrum of the neutrinos from NuMI.
The velocity of a ~3 GeV neutrino beam is measured by comparing detection times at the Near and Far detectors of the MINOS experiment, separated by 734 km. A total of 473 Far Detector neutrino events was used to measure (v-c)/c = 5.1 +/- 2.9 x 10^-5 (at 68% C.L.). By correlating the measured energies of 258 charged-current neutrino events to their arrival times at the Far Detector, a limit is imposed on the neutrino mass of m_nu < 50 MeV/c^2 (99% C.L.).
The MINOS experiment is a long-baseline neutrino experiment designed to study neutrino behaviour, in particular the phenomenon of neutrino oscillations. MINOS sends the NuMI neutrino beam through two detectors, a Near Detector 1 km downstream from the beam source at Fermilab, and a Far Detector 735 km away in the Soudan Mine in Minnesota. MINOS has been taking beam data since 2005. This document summarises recent neutrino oscillations results, with particular emphasis on electron neutrino appearance, which probes the angle $θ_{13}$ of the neutrino mass mixing matrix. For an exposure of 8.2$\ti…
This letter reports results from a search for muon-neutrino to electron-neutrino transitions by the MINOS experiment based on a 7x10^20 protons-on-target exposure. Our observation of 54 candidate electron-neutrino events in the Far Detector with a background of 49.1+/-7.0(stat.)+/-2.7(syst.) events predicted by the measurements in the Near Detector requires 2sin^2(2theta_{13})sin^2(theta_{23})<0.12 (0.20) at the 90% C.L. for the normal (inverted) mass hierarchy at delta_cp=0. The experiment sets the tightest limits to date on the value of theta_{13} for nearly all values of delta_cp for the no…
This letter reports new results from the MINOS experiment based on a two-year exposure to muon neutrinos from the Fermilab NuMI beam. Our data are consistent with quantum mechanical oscillations of neutrino flavor with mass splitting $|Δm^2|=(2.43\pm 0.13)\times10^{-3}$ eV$^2$ (68% confidence level) and mixing angle $\sin^2(2θ)>0.90$ (90% confidence level). Our data disfavor two alternative explanations for the disappearance of neutrinos in flight, namely neutrino decays into lighter particles and quantum decoherence of neutrinos, at the 3.7 and 5.7 standard deviation levels, respectively.
The MINOS experiment ran from 2003 until 2012 and collected a data sample including 10.71x10^20 protons-on-target (POT) of beam neutrinos, 3.36x10^20 POT of beam antineutrinos and an atmospheric neutrino exposure of 37.88 kt-yrs. The final measurement of the atmospheric neutrino oscillation parameters, dm^2_32 and theta_23, came from a full three flavour oscillation analysis of the combined CC nu_mu and CC anti-nu_mu beam and atmospheric samples and the CC nu_e and CC anti-nu_e appearance samples. This analysis yielded the most precise measurement of the atmospheric mass splitting dm^2_32 perf…
The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of muon neutrino and muon anti-neutrino charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations giving: R_data(up/down)/R_MC(up/down) = 0.62^{+0.19}_{-0.14} (stat.) +- 0.02 (sys.). An extended maximum likelihood …
A search for disappearance of active neutrinos over a baseline of 735 km was conducted using the NuMI neutrino beam and the MINOS detectors. The data analyzed correspond to an exposure of 3.18x10^{20} protons on target. The data are fitted to neutrino oscillation models in which mixing with one sterile neutrino is assumed. A comparison of the neutral-current-like spectrum at the FD with the expectation derived from the near detector measurement shows that the fraction of disappearing muon neutrinos converting to a sterile state is less than 52% at the 90% confidence level. In addition, the pos…
The MINOS/MINOS+ experiment has recently reported stringent limits on $ν_μ$ disappearance that appear to rule out the 3+1 sterile neutrino model. However, in this paper we wish to point out problems associated with the MINOS/MINOS+ analysis. In particular, we find that MINOS/MINOS+ has either underestimated their systematic errors and/or has obtained evidence for physics beyond the 3-neutrino paradigm. Either case would invalidate the limits on $ν_μ$ disappearance.
This letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 \pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |Δm^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3…
The MINOS experiment observes the NuMI beam produced by the Main Injector accelerator at two detector stations, one 1 km and the other 735 km from the neutrino production target. From the disappearance of neutrinos in flight between the two detectors, we measure the neutrino oscillation parameters $Δm_{23}^2$ and $\sin^2(2θ_{23})$ and update our previously published result. Additionally, we have searched for evidence of additional light neutrino families which do not couple to the weak interaction. Finally, we discuss the status of our search for the appearance of $ν_{e}$, an effect expected i…
The Main Injector Neutrino Oscillation search (MINOS) uses two detectors separated by 735km to measure a beam of neutrinos created by the Neutrinos at the Main Injector (NuMI) facility at Fermi National Accelerator Laboratory. The experiment has recently reported an observation of muon-neutrino disappearance consistent with neutrino oscillations. We describe the manner in which the experiment's results depend on the correct understanding and modeling of hadronic systems.
This letter reports on a search for $ν_μ\to ν_e$ transitions by the MINOS experiment based on a \unit[$3.14\times10^{20}$]{protons-on-target} exposure in the Fermilab NuMI beam. We observe 35 events in the Far Detector with a background of $27\pm 5 {\rm (stat.)} \pm 2 {\rm (syst.)$ events predicted by the measurements in the Near Detector. If interpreted in terms of $ν_μ\to ν_e$ oscillations, this 1.5 $σ$ excess of events is consistent with $\sin^{2}(2θ_{13})$ comparable to the CHOOZ limit when $|\delmsq{}|$=\unit[2.43$\times 10^{-3}$] {${\rm eV^{2}}$} and \sinsq{23}=1.0 are assumed.
MINOS is a long baseline neutrino oscillation experiment designed to make precision measurements of the neutrino mixing parameters associated with the atmospheric neutrino mass splitting. Using a neutrino beam from the Main Injector (NuMI) facility at Fermilab, it compares the neutrino energy spectrum for neutrino interactions observed in two large detectors located at Fermilab and in the Soudan mine in northern Minnesota at a distance of 735km. We describe initial results for electron neutrino appearance in MINOS after two years of data-taking. We observe 35 events in the Far Detector with a …
This document presents the latest results for a 3+1 sterile neutrino search using the $10.56 \times 10^{20}$ protons-on-target data set taken from 2005 - 2012. By searching for oscillations driven by a large mass splitting, MINOS is sensitive to the existence of sterile neutrinos through any energy dependent deviations using a charged current sample, as well as looking at any relative deficit between neutral current events between the far and near detectors. This document will discuss the novel analysis that enabled a search for sterile neutrinos setting a limit in the previously unexplored re…
The MINOS experiment is now making precise measurements of the nu_mu disappearance oscillations seen in atmospheric neutrinos, and will extend our reach towards the so far unseen theta_13 by looking for nu_e appearance in the nu_mu beam. It does so by using the intense, well-understood NuMI neutrino beam created at Fermilab and observing it 735 km away at the Soudan Mine in Northeast Minnesota. Results from MINOS' first two years of operations will be presented.
The MINOS experiment took data for seven years between May 2005 and April 2012. Since then it has been reborn as the new MINOS+ experiment in the upgraded medium energy NuMI beam and started taking data in September 2013. An update to the MINOS standard oscillations three-flavour disappearance analysis is presented which includes 28% more atmospheric neutrino data. This combined three-flavour analysis calculates an atmospheric parameter best-fit point of $Δm_{32}^{2}=2.37^{+0.11}_{-0.07} \times 10^{-3}$~eV$^{2}$ and $\sin^{2}θ_{23}=0.43^{+0.19}_{-0.05}$ for the inverted hierarchy, for which th…
The energy dependence of the neutrino-iron and antineutrino-iron inclusive charged-current cross sections and their ratio have been measured using a high-statistics sample with the MINOS Near Detector exposed to the NuMI beam from the Main Injector at Fermilab. Neutrino and antineutrino fluxes were determined using a low hadronic energy subsample of charged-current events. We report measurements of neutrino-Fe (antineutrinoFe) cross section in the energy range 3-50 GeV (5-50 GeV) with precision of 2-8% (3-9%) and their ratio which is measured with precision 2-8%. The data set spans the region …
The MINOS Collaboration continues its search for $ν_e$ appearance in the NuMI (Neutrinos at the Main Injector) beam at Fermilab. Neutrinos in the beam interact in the Near Detector, located 1 km from the beam source, allowing us to characterize the backgrounds present in our analysis. In particular, we can estimate the number of $ν_e$ candidate events we expect to see in the Far Detector (735 km away, in the Soudan mine in northern Minnesota) in the presence or absence of $ν_μ\rightarrow ν_e$ oscillation. Recent efforts to improve the sensitivity of the analysis, including upgrades to the even…
We found 140 neutrino-induced muons in 854.24 live days in the MINOS far detector. We looked for evidence of neutrino disappearance in this data set by computing the ratio of the number of low momentum muons to the sum of the number of high momentum and unknown momentum muons for both data and Monte Carlo expectation in the absence of neutrino oscillations. The ratio of data and Monte Carlo ratios is consistent with an oscillation signal. A fit to the data for the oscillation parameters excludes the null oscillation hypothesis at the 94% confidence level. We separated the muons by charge sign …
We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between muon neutirnos and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of muon neutrino oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible c…
The MINOS long baseline experiment has been collecting neutrino beam data since March 2005 and has accumulated 3 x 10^{20} protons-on-target (POT) to date. MINOS uses Fermilab's NuMI neutrino beam which is measured by two steel-scintillator tracking calorimeters, one at Fermilab and the other 735 km downstream, in northern Minnesota. By observing the oscillatory structure in the neutrino energy spectrum, MINOS can precisely measure the neutrino oscillation parameters in the atmospheric sector. From analysis of the first year of data, corresponding to 1.27 x 10^{20} POT, these parameters were d…
A search for depletion of the combined flux of active neutrino species over a 735 km baseline is reported using neutral-current interaction data recorded by the MINOS detectors in the NuMI neutrino beam. Such a depletion is not expected according to conventional interpretations of neutrino oscillation data involving the three known neutrino flavors. A depletion would be a signature of oscillations or decay to postulated non-interacting "sterile" neutrinos, scenarios not ruled out by existing data. From an exposure of 3.18x10^{20} protons on target in which neutrinos of energies between ~500 Me…
The results from the initial exposure of the MINOS detectors to neutrinos produced by the Fermilab NuMI beam are reported here. The exposure consisted of 1.27 x 10^{20} 120 GeV protons incident on the NuMI target. The data show the observation of 215 neutrinos with energies below 30 GeV while 336 +/- 14.4 events were expected. The data are consistent with nu_mu disappearance via neutrino oscillations.
This paper discusses recent results and near-term prospects of the long-baseline neutrino experiments MINOS, MINOS+, T2K and NOvA. The non-zero value of the third neutrino mixing angle θ13 allows experimental analysis in a manner which explicitly exhibits appearance and disappearance dependencies on additional parameters associated with mass-hierarchy, CP violation, and any non-maximal θ23. These current and near-future experiments begin the era of precision accelerator long-baseline measurements and lay the framework within which future experimental results will be interpreted.
The Main Injector Neutrino Oscillation Search (MINOS) experiment's primary goal is the precision measurement of the neutrino oscillation parameters in the atmospheric neutrino sector. This long-baseline experiment uses Fermilab's NuMI beam, measured with a Near Detector at Fermilab, and again 735 km later using a Far Detector in the Soudan Mine Underground Lab in northern Minnesota. The detectors are magnetized iron/scintillator calorimeters. The Far Detector has been operational for cosmic ray and atmospheric neutrino data from July of 2003, the Near Detector from September 2004, and the NuMI…
The observed neutrino flavor transitions are currently explained by the three flavor neutrino oscillation phenomenon, considered to be the leading order mechanism behind the flavor transitions. Currently existing data from LSND, MiniBooNE and reactor experiments demonstrate anomalies that could potentially be indications of non-standard neutrino phenomena. MINOS can probe transitions from muon neutrinos to electron neutrinos and search for anomalous behavior that cannot be explained by standard model neutrino oscillations. Here we present the search for second order effects in the flavor trans…
MINOS will measure the composition of a neutrino beam at two locations, 735km apart, in an effort confirm the (atmospheric) neutrino oscillation hypothesis and measure the associated mixing parameters. Oscillations will be manifested as a difference in the rate and energy spectrum of muon neutrino CC interactions measured in the two detectors. Because most interactions observed in MINOS are inelastic, the neutrino energy is reconstructed as the sum of the energy carried by the muon and that seen in the hadronic shower emanating from the struck nucleus. The latter is sensitive to uncertainties …
We searched for a sidereal modulation in the rate of neutrinos observed by the MINOS far detector. The detection of these 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.
Prospect measurements of neutrino oscillations with reactor neutrinos are reviewed in this document. The following items are described: neutrinos oscillations status, reactor neutrino experimental strategy, impact of uncertainties on the neutrino oscillation sensitivity and, finally, the experiments in the field. This is the synthesis of the talk delivered during the NOW2006 conference at Otranto (Italy) during September 2006.
The MINOS experiment took data from 2005 up until 2012. This was superseded by MINOS+, the continuation of the two-detector, on-axis, long-baseline experiment based at Fermilab, and at the Soudan Underground Laboratory in northern Minnesota. By searching for the deficit of muon neutrinos at the Far Detector, MINOS/MINOS+ is sensitive to the atmospheric neutrino oscillation parameters $Δm^{2}_{32}$ and $θ_{23}$. By using the full MINOS data set looking at both \numu disappearance and \nue appearance in both neutrino and anti-neutrino configurations at the NuMI beam along with atmospheric neutri…
A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 km and 735 km, using a combined MINOS and MINOS+ exposure of $16.36\times10^{20}$ protons-on-target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter $\sin^2θ_{24}$ for most values of the sterile neutrino mass-splitting $Δm^2…
The phenomenon of neutrino oscillation has been firmly established: neutrinos change their flavor in their path from their source to observers. This paper is dedicated to the description of experimental results in the oscillation field, of their present understanding and of possible future developments in experimental neutrino oscillation physics.
Recent results on neutrino oscillations and neutrino masses are presented. The most exciting news are the Super-Kamiokande measurements of atmospheric neutrinos, which show evidence for the neutrinos being massive. Various possible schemes for the neutrino masses are discussed.
This article reviews the many new results from neutrino oscillation searches which were presented at ICHEP '98. Exciting indications of neutrino oscillations have been seen in the solar neutrino deficit, atmospheric neutrino deficit and LSND excess. These indications and reported limits on oscillations are considered. Attempts to develop a theory which addresses all of the neutrino oscillation data are discussed. Some of the remaining questions and the future experiments which will help answer these questions are described.
The MINOS experiment at Fermilab has recently reported a tension between the oscillation results for neutrinos and anti-neutrinos. We show that this tension, if it persists, can be understood in the framework of non-standard neutrino interactions (NSI). While neutral current NSI (non-standard matter effects) are disfavored by atmospheric neutrinos, a new charged current coupling between tau neutrinos and nucleons can fit the MINOS data without violating other constraints. In particular, we show that loop-level contributions to flavor-violating tau decays are sufficiently suppressed. However, c…
We present results for muon neutrino oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced muon neutrino beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy dependent disappearance of muon neutrino, which we presume have oscillated to tau neutrino. The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).
A search for day-night variations in the solar neutrino flux resulting from neutrino oscillations has been carried out using the 504 day sample of solar neutrino data obtained at Super-Kamiokande. The absence of a significant day-night variation has set an absolute flux independent exclusion region in the two neutrino oscillation parameter space.
Driven by new experimental results, in the latest period several new neutrino oscillation experiments have been proposed. I will outline the main ideas behind the different proposals, in particular concerning atmospheric neutrinos and neutrinos from accelerated beams.
A long-baseline neutrino-oscillation experiment using a well-defined neutrino beam is in preparation at KEK. Neutrinos generated at KEK will be detected by the Super-kamiokande detector 250 km away. The design of the neutrino beam line, beam monitors and detector are briefly presented. The sensitivities for neutrino oscillations are also discussed.
We study the $ν_μ- ν_s$ oscillation effects in the near detector of the MINOS experiment. Conceptually, the MINOS search for sterile neutrinos with mass $\sim 1$ eV realizes an interesting situation of partial decoherence of the neutrino state at the production. This corresponds to a difference of energies of the two mass eigenstates that is comparable with or bigger than the width of the initial state (pion). We show that these effects modify the MINOS bound on mixing of sterile neutrino for $Δm^2_{41} \aprge 0.5$ eV$^2$ and make the experiment insensitive to oscillations with $Δm^2_{41} \gtr…
The 4.8$σ$ anomaly in MiniBooNE data cannot be reconciled with MINOS+ and IceCube data within the vanilla framework of neutrino oscillations involving an eV-mass sterile neutrino. We show that an apparently consistent picture can be drawn if charged-current and neutral-current nonstandard neutrino interactions are at work in the 3+1 neutrino scheme. It appears that either the neutrino sector is more elaborate than usually envisioned, or one or more datasets needs revision.
A search for a sidereal modulation in the MINOS near detector neutrino data was performed. If present, this signature could be a consequence of Lorentz and CPT violation as predicted by a class of extensions to the Standard Model. No evidence for a sidereal signal in the data set was found, implying that there is no significant change in neutrino propagation that depends on the direction of the neutrino beam in a sun-centered inertial frame. Upper limits on the magnitudes of the Lorentz and CPT violating terms in these extensions to the Standard Model lie between 0.01-1% of the maximum expecte…
We perform a detailed analysis of the capabilities of the MINOS, ICARUS and OPERA experiments to measure neutrino oscillation parameters at the atmospheric scale with their data taken separately and in combination. MINOS will determine $Δm^2_{32}$ and $\sin^2 2θ_{23}$ to within 10% at the 99% C.L. with 10 kton-years of data. While no one experiment will determine $\sin^2 2θ_{13}$ with much precision, if its value lies in the combined sensitivity region of the three experiments, it will be possible to place a lower bound of O(0.01) at the 95% C.L. on this parameter by combining the data from th…
The SuperKamiokande atmospheric neutrino measurements leave substantial room for nonstandard interactions (NSI) of neutrinos with matter in the nu_e- nu_tau sector. Large values of the NSI couplings are accommodated if the vacuum oscillation parameters are changed from their standard values. Short and medium baseline neutrino beams can break this degeneracy by measuring the true vacuum oscillation parameters with the muon neutrino disappearance mode, for which the matter effects are negligible or subdominant. These experiments can also search for the nu_e-nu_tau flavor changing effects directl…
Recent neutrino oscillation results have evoked renewed interest in sterile neutrino oscillation models. This paper reviews the data from MiniBooNE and short-baseline reactor antineutrino experiments within the context of sterile neutrinos. The results are incorporated into combined fits to test the viability of sterile neutrino oscillation models, which are later expanded to address matter effects. Finally, future experiments that can resolve the questions that have been raised are discussed.
I review explanations for the three neutrino anomalies (solar, atmospheric and LSND) which go beyond the ``conventional'' neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well.
Neutrino oscillation results from several experiments and sources are discussed. Recent results from solar neutrino measurements by Super-Kamiokande and Borexino, atmospheric neutrino measurements from Super-Kamiokande, and accelerator neutrino measurements by MINOS and OPERA are the main topics of this document.
Adopting neutrino oscillation parameters obtained by Super-Kamiokande, a numerical computer experiment for neutrino events occurring outside the detector, is carried out in the same SK live days, 1645.9 live days, constructing the virtual Super-Kamiokande detector in the computer. The numerical results by the computer experiment could be directly compared with the real SK experimental data. The comparison shows that it is difficult to obtain convincing conclusion on the existence of the neutrino oscillation with specified neutrino oscillation parameters claimed by SK through analysis for neutr…
Precise tests of Lorentz invariance in neutrinos can be performed using long baseline experiments such as MINOS and OPERA or neutrinos from astrophysical sources. The MINOS collaboration reported a measurement of the muonic neutrino velocities that hints to super-luminal propagation, very recently confirmed at 6 sigma by OPERA. We consider a general parametrisation which goes beyond the usual linear or quadratic violation considered in quantum-gravitational models. We also propose a toy model showing why Lorentz violation can be specific to the neutrino sector and give rise to a generic energy…
