arXiv subjects

T. J. Carroll

Publications and source records attributed to T. J. Carroll.

At least 37 records · Page 2Linked to original sources

arXiv2021

Search for multi-messenger signals in NOvA coincident with LIGO/Virgo detections

Using the NOvA neutrino detectors, a broad search has been performed for any signal coincident with 28 gravitational wave events detected by the LIGO/Virgo Collaboration between September 2015 and July 2019. For all of these events, NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and higher energies. For five (seven) events in the NOvA Far (Near) Detector, timely public alerts from the LIGO/Virgo Collaboration allowed recording of MeV-scale events. No signal candidates were found.

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arXiv2021

Search for Slow Magnetic Monopoles with the NOvA Detector on the Surface

We report a search for a magnetic monopole component of the cosmic-ray flux in a 95-day exposure of the NOvA experiment's Far Detector, a 14 kt segmented liquid scintillator detector designed primarily to observe GeV-scale electron neutrinos. No events consistent with monopoles were observed, setting an upper limit on the flux of $2\times 10^{-14} \mathrm{cm^{-2}s^{-1}sr^{-1}}$ at 90% C.L. for monopole speed $6\times 10^{-4} < β< 5\times 10^{-3}$ and mass greater than $5\times 10^{8}$ GeV. Because of NOvA's small overburden of 3 meters-water equivalent, this constraint covers a previously unexplored low-mass region.

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arXiv2020

Adjusting Neutrino Interaction Models and Evaluating Uncertainties using NOvA Near Detector Data

The two-detector design of the NOvA neutrino oscillation experiment, in which two functionally identical detectors are exposed to an intense neutrino beam, aids in canceling leading order effects of cross-section uncertainties. However, limited knowledge of neutrino interaction cross sections still gives rise to some of the largest systematic uncertainties in current oscillation measurements. We show contemporary models of neutrino interactions to be discrepant with data from NOvA, consistent with discrepancies seen in other experiments. Adjustments to neutrino interaction models in GENIE that improve agreement with our data are presented. We also describe systematic uncertainties on these models, including uncertainties on multi-nucleon interactions from a newly developed procedure using NOvA near detector data.

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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

Supernova neutrino detection in NOvA

The NOvA long-baseline neutrino experiment uses a pair of large, segmented, liquid-scintillator calorimeters to study neutrino oscillations, using GeV-scale neutrinos from the Fermilab NuMI beam. These detectors are also sensitive to the flux of neutrinos which are emitted during a core-collapse supernova through inverse beta decay interactions on carbon at energies of $\mathcal{O}(10~\text{MeV})$. This signature provides a means to study the dominant mode of energy release for a core-collapse supernova occurring in our galaxy. We describe the data-driven software trigger system developed and employed by the NOvA experiment to identify and record neutrino data from nearby galactic supernovae. This technique has been used by NOvA to self-trigger on potential core-collapse supernovae in our galaxy, with an estimated sensitivity reaching out to 10~kpc distance while achieving a detection efficiency of 23\% to 49\% for supernovae from progenitor stars with masses of 9.6M$_\odot$ to 27M$_\odot$, respectively.

physics.ins-det↗

arXiv2020

Measurement of Neutrino-Induced Neutral-Current Coherent $π^0$ Production in the NOvA Near Detector

The cross section of neutrino-induced neutral-current coherent $π^0$ production on a carbon-dominated target is measured in the NOvA near detector. This measurement uses a narrow-band neutrino beam with an average neutrino energy of 2.7\,GeV, which is of interest to ongoing and future long-baseline neutrino oscillation experiments. The measured, flux-averaged cross section is $σ= 13.8\pm0.9 (\text{stat})\pm2.3 (\text{syst}) \times 10^{-40}\,\text{cm}^2/\text{nucleus}$, consistent with model prediction. This result is the most precise measurement of neutral-current coherent $π^0$ production in the few-GeV neutrino energy region.

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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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arXiv2020

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the $θ_{μe}$ mixing angle are derived that constitute the most stringent limits to date over five orders of magnitude in the sterile mass-squared splitting $Δm^2_{41}$, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL$_s$ for $Δm^2_{41}<5\,$eV$^2$.Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL$_s$ for $Δm^2_{41}$ $<$ 1.2 eV$^2$.

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arXiv2019

Observation of seasonal variation of atmospheric multiple-muon events in the NOvA Near Detector

Using two years of data from the NOvA Near Detector at Fermilab, we report a seasonal variation of cosmic ray induced multiple-muon event rates which has an opposite phase to the seasonal variation in the atmospheric temperature. The strength of the seasonal multipl$ increase as a function of the muon multiplicity. However, no significant dependence of the strength of the seasonal variation of the multiple-muon variation is seen as a function of the muon zenith angle, or the spatial or angular separation between the correlated muons.

physics.ins-det↗

arXiv2019

First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA

The NOvA experiment has made a $4.4σ$-significant observation of $\barν_{e}$ appearance in a 2 GeV $\barν_μ$ beam at a distance of 810 km. Using $12.33\times10^{20}$ protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 $\barν_μ \rightarrow \barν_{e}$ candidates with a background of 10.3 and 102 $\barν_μ \rightarrow \barν_μ$ candidates. This new antineutrino data is combined with neutrino data to measure the oscillation parameters $|Δm^2_{32}| = 2.48^{+0.11}_{-0.06}\times10^{-3}$ eV$^2/c^4$, $\sin^2 θ_{23} = 0.56^{+0.04}_{-0.03}$ in the normal neutrino mass hierarchy and upper octant and excludes most values near $δ_{\rm CP}=π/2$ for the inverted mass hierarchy by more than 3$σ$. The data favor the normal neutrino mass hierarchy by 1.9$σ$ and $θ_{23}$ values in the upper octant by 1.6$σ$.

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arXiv2018

New constraints on oscillation parameters from $ν_e$ appearance and $ν_μ$ disappearance in the NOvA experiment

We present updated results from the NOvA experiment for $ν_μ\rightarrowν_μ$ and $ν_μ\rightarrowν_e$ oscillations from an exposure of $8.85\times10^{20}$ protons on target, which represents an increase of 46% compared to our previous publication. The results utilize significant improvements in both the simulations and analysis of the data. A joint fit to the data for $ν_μ$ disappearance and $ν_e$ appearance gives the best fit point as normal mass hierarchy, $Δm^2_{32} = 2.44\times 10^{-3}{{\rm eV}^2}/c^4$, $\sin^2θ_{23} = 0.56$, and $δ_{CP} = 1.21π$. The 68.3% confidence intervals in the normal mass hierarchy are $Δm^2_{32} \in [2.37,2.52]\times 10^{-3}{{\rm eV}^2}/c^4$, $\sin^2θ_{23} \in [0.43,0.51] \cup [0.52,0.60]$, and $δ_{CP} \in [0,0.12π] \cup [0.91π,2π]$. The inverted mass hierarchy is disfavored at the 95% confidence level for all choices of the other oscillation parameters.

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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

Measuring the Attenuation Length of Water in the CHIPS-M Water Cherenkov Detector

The water at the proposed site of the CHIPS water Cherenkov detector has been studied to measure its attenuation length for Cherenkov light as a function of filtering time. A scaled model of the CHIPS detector filled with water from the Wentworth 2W pit, proposed site of the CHIPS deployment, in conjunction with a 3.2\unit{m} vertical column filled with this water, was used to study the transmission of 405nm laser light. Results consistent with attenuation lengths of up to 100m were observed for this wavelength with filtration and UV sterilization alone.

physics.ins-det↗

arXiv2016

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the LSND and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on $\sin^2 2θ_{μe}$ are set over 6 orders of magnitude in the sterile mass-squared splitting $Δm^2_{41}$. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for $Δm^2_{41} < 0.8$ eV$^2$ at 95% CL$_s$.

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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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