arXiv subjects

J. Schneps

Publications and source records attributed to J. Schneps.

At least 19 recordsLinked to original sources

arXiv2020

Precision constraints for three-flavor neutrino oscillations from the full MINOS+ and MINOS data set

We report the final measurement of the neutrino oscillation parameters $Δm^2_{32}$ and $\sin^2θ_{23}$ using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of $23.76 \times 10^{20}$ protons on target producing $ν_{mu}$ and $\overline{ν_μ}$ beams and 60.75 kt$\cdot$yr exposure to atmospheric neutrinos. The measurement of the disappearance of $ν_μ$ and the appearance of $ν_e$ events between the Near and Far detectors yields $|Δm^2_{32}|=2.40^{+0.08}_{-0.09}~(2.45^{+0.07}_{-0.08}) \times 10^{-3}$ eV$^2$ and $\sin^2θ_{23} = 0.43^{+0.20}_{-0.04} ~(0.42^{+0.07}_{-0.03})$ at 68% C.L. for Normal (Inverted) Hierarchy.

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arXiv2020

Search for sterile neutrinos in MINOS and MINOS+ using a two-detector fit

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 $Δm^2_{41} > 10^{-4}$ eV$^2$.

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arXiv2017

Constraints on Large Extra Dimensions from the MINOS Experiment

We report new constraints on the size of large extra dimensions from data collected by the MINOS experiment between 2005 and 2012. Our analysis employs a model in which sterile neutrinos arise as Kaluza-Klein states in large extra dimensions and thus modify the neutrino oscillation probabilities due to mixing between active and sterile neutrino states. Using Fermilab's NuMI beam exposure of $10.56 \times 10^{20}$ protons-on-target, we combine muon neutrino charged current and neutral current data sets from the Near and Far Detectors and observe no evidence for deviations from standard three-flavor neutrino oscillations. The ratios of reconstructed energy spectra in the two detectors constrain the size of large extra dimensions to be smaller than $0.45\,μ\text{m}$ at 90% C.L. in the limit of a vanishing lightest active neutrino mass. Stronger limits are obtained for non-vanishing masses.

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arXiv2016

A search for flavor-changing non-standard neutrino interactions using $ν_{e}$ appearance in MINOS

We report new constraints on flavor-changing non-standard neutrino interactions from the MINOS long-baseline experiment using $ν_{e}$ and $\barν_{e}$ appearance candidate events from predominantly $ν_μ$ and $\barν_μ$ beams. We used a statistical selection algorithm to separate $ν_{e}$ candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the non-standard interaction matter effect, $|\varepsilon_{eτ}|$, and phase, $(δ_{CP}+δ_{eτ})$, using a thirty-bin likelihood fit.

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arXiv2016

Search for time-independent Lorentz violation using muon neutrino to muon antineutrino transitions in MINOS

Data from the MINOS experiment has been used to search for mixing between muon neutrinos and muon antineutrinos using a time-independent Lorentz-violating formalism derived from the Standard-Model Extension (SME). MINOS is uniquely capable of searching for muon neutrino-antineutrino mixing given its long baseline and ability to distinguish between neutrinos and antineutrinos on an event-by-event basis. Neutrino and antineutrino interactions were observed in the MINOS Near and Far Detectors from an exposure of 10.56$\times10^{20}$ protons-on-target from the NuMI neutrino-optimized beam. No evidence was found for such transitions and new, highly stringent limits were placed on the SME coefficients governing them. We place the first limits on the SME parameters $(c_{L})^{TT}_{μμ} $ and $(c_{L})^{TT}_{ττ}$ at $-8.4\times10^{-23} < (c_{L})^{TT}_{μμ} < 8.0\times10^{-23}$ and $-8.0\times10^{-23} < (c_{L})^{TT}_{ττ} < 8.4\times10^{-23}$, and the world's best limits on the $\tilde{g}^{ZT}_{μ\overlineμ}$ and $\tilde{g}^{ZT}_{τ\overlineτ}$ parameters at $|\tilde{g}^{ZT}_{μ\overlineμ}| < 3.3\times 10^{-23}$ and $|\tilde{g}^{ZT}_{τ\overlineτ}| < 3.3\times 10^{-23}$, all limits quoted at $3σ$.

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arXiv2016

Measurement of single $π^0$ production by coherent neutral-current $ν$ Fe interactions in the MINOS Near Detector

Forward single $π^0$ production by coherent neutral-current interactions, $ν\mathcal{A} \to ν\mathcal{A} π^0$, is investigated using a 2.8$\times 10^{20}$ protons-on-target exposure of the MINOS Near Detector. For single-shower topologies, the event distribution in production angle exhibits a clear excess above the estimated background at very forward angles for visible energy in the range~1-8 GeV. Cross sections are obtained for the detector medium comprised of 80% iron and 20% carbon nuclei with $\langle \mathcal{A} \rangle = 48$, the highest-$\langle \mathcal{A} \rangle$ target used to date in the study of this coherent reaction. The total cross section for coherent neutral-current single-$π^0$ production initiated by the $ν_μ$ flux of the NuMI low-energy beam with mean (mode) $E_ν$ of 4.9 GeV (3.0 GeV), is $77.6\pm5.0\,(\text{stat}) ^{+15.0}_{-16.8}\,(\text{syst})\times10^{-40}\,\text{cm}^2~\text{per nucleus}$. The results are in good agreement with predictions of the Berger-Sehgal model.

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arXiv2016

Search for Sterile Neutrinos Mixing with Muon Neutrinos in MINOS

We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and $735\,\mathrm{km}$ in a $ν_μ$-dominated beam with a peak energy of $3\,\mathrm{GeV}$. The data, from an exposure of $10.56\times 10^{20}\,\textrm{protons on target}$, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters $θ_{24}$ and $Δm^{2}_{41}$ and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, $|U_{μ4}|^{2}$ and $|U_{τ4}|^{2}$, under the assumption that mixing between $ν_{e}$ and $ν_{s}$ is negligible ($|U_{e4}|^{2}=0$). No evidence for $ν_μ \to ν_{s}$ transitions is found and we set a world-leading limit on $θ_{24}$ for values of $Δm^{2}_{41} \lesssim 1\,\mathrm{eV}^{2}$.

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arXiv2016

Measurement of the Multiple-Muon Charge Ratio in the MINOS Far Detector

The charge ratio, $R_μ= N_{μ^+}/N_{μ^-}$, for cosmogenic multiple-muon events observed at an under- ground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be $R_μ= 1.104 \pm 0.006 {\rm \,(stat.)} ^{+0.009}_{-0.010} {\rm \,(syst.)} $. This measurement complements previous determinations of single-muon and multiple-muon charge ratios at underground sites and serves to constrain models of cosmic ray interactions at TeV energies.

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arXiv2015

Precision measurement of the speed of propagation of neutrinos using the MINOS detectors

We report a two-detector measurement of the propagation speed of neutrinos over a baseline of 734 km. The measurement was made with the NuMI beam at Fermilab between the near and far MINOS detectors. The fractional difference between the neutrino speed and the speed of light is determined to be $(v/c-1) = (1.0 \pm 1.1) \times 10^{-6}$, consistent with relativistic neutrinos.

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arXiv2015

Observation of seasonal variation of atmospheric multiple-muon events in the MINOS Near and Far Detectors

We report the first observation of seasonal modulations in the rates of cosmic ray multiple-muon events at two underground sites, the MINOS Near Detector with an overburden of 225 mwe, and the MINOS Far Detector site at 2100 mwe. At the deeper site, multiple-muon events with muons separated by more than 8 m exhibit a seasonal rate that peaks during the summer, similar to that of single-muon events. In contrast and unexpectedly, the rate of multiple-muon events with muons separated by less than 5-8 m, and the rate of multiple-muon events in the smaller, shallower Near Detector, exhibit a seasonal rate modulation that peaks in the winter.

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arXiv2014

Study of quasielastic scattering using charged-current nu_mu-iron interactions in the MINOS Near Detector

Kinematic distributions from an inclusive sample of 1.41 x 10^6 charged-current nu_mu interactions on iron, obtained using the MINOS Near Detector exposed to a wide-band beam with peak flux at 3 GeV, are compared to a conventional treatment of neutrino scattering within a Fermi gas nucleus. Results are used to guide the selection of a subsample enriched in quasielastic nu_mu Fe interactions, containing an estimated 123,000 quasielastic events of incident energies 1 < E_nu < 8 GeV, with = 2.79 GeV. Four additional subsamples representing topological and kinematic sideband regions to quasielastic scattering are also selected for the purpose of evaluating backgrounds. Comparisons using subsample distributions in four-momentum transfer Q^2 show the Monte Carlo model to be inadequate at low Q^2. Its shortcomings are remedied via inclusion of a Q^2-dependent suppression function for baryon resonance production, developed from the data. A chi-square fit of the resulting Monte Carlo simulation to the shape of the Q^2 distribution for the quasielastic-enriched sample is carried out with the axial-vector mass M_A of the dipole axial-vector form factor of the neutron as a free parameter. The effective M_A which best describes the data is 1.23 +0.13/-0.09 (fit) +0.12/-0.15 (syst.) GeV.

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arXiv2014

Observation of muon intensity variations by season with the MINOS Near Detector

A sample of 1.53$\times$10$^{9}$ cosmic-ray-induced single muon events has been recorded at 225 meters-water-equivalent using the MINOS Near Detector. The underground muon rate is observed to be highly correlated with the effective atmospheric temperature. The coefficient $α_{T}$, relating the change in the muon rate to the change in the vertical effective temperature, is determined to be 0.428$\pm$0.003(stat.)$\pm$0.059(syst.). An alternative description is provided by the weighted effective temperature, introduced to account for the differences in the temperature profile and muon flux as a function of zenith angle. Using the latter estimation of temperature, the coefficient is determined to be 0.352$\pm$0.003(stat.)$\pm$0.046(syst.).

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arXiv2014

Combined analysis of $ν_μ$ disappearance and $ν_μ \rightarrow ν_{e}$ appearance in MINOS using accelerator and atmospheric neutrinos

We report on a new analysis of neutrino oscillations in MINOS using the complete set of accelerator and atmospheric data. The analysis combines the $ν_μ$ disappearance and $ν_{e}$ appearance data using the three-flavor formalism. We measure $|Δm^{2}_{32}|=[2.28-2.46]\times10^{-3}\mbox{\,eV}^{2}$ (68% C.L.) and $\sin^{2}θ_{23}=0.35-0.65$ (90% C.L.) in the normal hierarchy, and $|Δm^{2}_{32}|=[2.32-2.53]\times10^{-3}\mbox{\,eV}^{2}$ (68% C.L.) and $\sin^{2}θ_{23}=0.34-0.67$ (90% C.L.) in the inverted hierarchy. The data also constrain $δ_{CP}$, the $θ_{23}$ octant degeneracy and the mass hierarchy; we disfavor 36% (11%) of this three-parameter space at 68% (90%) C.L.

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arXiv2013

Measurement of Neutrino and Antineutrino Oscillations Using Beam and Atmospheric Data in MINOS

We report measurements of oscillation parameters from $ν_{mu}$ and $\barν_μ$ disappearance using beam and atmospheric data from MINOS. The data comprise exposures of \unit[$10.71 \times 10^{20}$]{protons on target (POT)} in the $ν_μ$-dominated beam, $\unit[3.36\times10^{20}]{POT}}$ in the $\barν_μ$-enhanced beam, and 37.88 kton-years of atmospheric neutrinos. Assuming identical $ν$ and $\barν$ oscillation parameters, we measure \mbox{$|Δm^2}| = \unit[2.41^{+0.09}_{-0.10}) \times 10^{-3}]{eV^{2}}$} and $\sin^{2}/!/left(2θ\right) = 0.950^{+0.035}_{-0.036}$. Allowing independent $ν$ and $\barν$ oscillations, we measure antineutrino parameters of $|Δ\bar{m}^2| = \unit[(2.50 ^{+0.23}_{-0.25}) \times 10^{-3}]{eV^{2}}$ and $\sin^{2}/!/left(2\barθ \right) = 0.97^{+0.03}_{-0.08}$, with minimal change to the neutrino parameters.

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arXiv2013

Electron neutrino and antineutrino appearance in the full MINOS data sample

We report on $ν_e$ and $\barν_e$ appearance in $ν_μ$ and $\barν_μ$ beams using the full MINOS data sample. The comparison of these $ν_e$ and $\barν_e$ appearance data at a 735 km baseline with $θ_{13}$ measurements by reactor experiments probes $δ$, the $θ_{23}$ octant degeneracy, and the mass hierarchy. This analysis is the first use of this technique and includes the first accelerator long-baseline search for $\barν_μ\rightarrow\barν_e$. Our data disfavor 31% (5%) of the three-parameter space defined by $δ$, the octant of the $θ_{23}$, and the mass hierarchy at the 68% (90%) C.L. We measure a value of 2sin$^2(2θ_{13})$sin$^2(θ_{23})$ that is consistent with reactor experiments.

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arXiv2013

A search for flavor-changing non-standard neutrino interactions by MINOS

We report new constraints on flavor-changing non-standard neutrino interactions (NSI) using data from the MINOS experiment. We analyzed a combined set of beam neutrino and antineutrino data, and found no evidence for deviations from standard neutrino mixing. The observed energy spectra constrain the NSI parameter to the range $-0.20 < \varepsilon_{μτ} < 0.07\;\text{(90% C.L.)}$

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arXiv2012

Measurements of atmospheric neutrinos and antineutrinos in the MINOS Far Detector

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current $ν_μ$ and $\barν_μ$ interactions, and 701 contained-vertex showers, composed mainly of charged-current $ν_{e}$ and $\barν_{e}$ interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of $ν_μ$ and $\barν_μ$ events. The observed ratio of $\barν_μ$ to $ν_μ$ events is compared with the Monte Carlo simulation, giving a double ratio of $R^{data}_{\barν/ν}/R^{MC}_{\barν/ν} = 1.03 \pm 0.08 (stat.) \pm 0.08 (syst.)$. The $ν_μ$ and $\barν_μ$ data are separated into bins of $L/E$ resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed $L/E$ distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of $|Δm^{2}| = (1.9 \pm 0.4) \times 10^{-3} eV^{2}$ and $sin^{2} 2θ> 0.86$. The fit is extended to incorporate separate $ν_μ$ and $\barν_μ$ oscillation parameters, returning 90% confidence limits of $|Δm^{2}|-|Δ\bar{m}^{2}| = 0.6^{+2.4}_{-0.8} \times 10^{-3} eV^{2}$ on the difference between the squared-mass splittings for neutrinos and antineutrinos.

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arXiv2012

An improved measurement of muon antineutrino disappearance in MINOS

We report an improved measurement of muon anti-neutrino disappearance over a distance of 735km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a muon anti-neutrino enhanced configuration. From a total exposure of 2.95e20 protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of the anti-neutrino "atmospheric" delta-m squared = 2.62 +0.31/-0.28 (stat.) +/- 0.09 (syst.) and constrain the anti-neutrino atmospheric mixing angle >0.75 (90%CL). These values are in agreement with those measured for muon neutrinos, removing the tension reported previously.

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