arXiv subjects

J. Lozier

Publications and source records attributed to J. Lozier.

7 recordsLinked to original sources

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.

hep-ex↗

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$σ$.

hep-ex↗

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.

hep-ex↗

arXiv2017

Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810\,km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05$\times$10$^{20}$ protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with $83.5 \pm 9.7 \mbox{(stat.)} \pm 9.4 \mbox{(syst.)}$ events predicted assuming mixing only occurs between active neutrino species. No evidence for $ν_μ \rightarrow ν_{s}$ transitions is found. Interpreting these results within a 3+1 model, we place constraints on the mixing angles $θ_{24}<20.8^{\circ}$ and $θ_{34}<31.2^{\circ}$ at the 90% C.L. for $0.05~eV^2\leq Δm^2_{41}\leq 0.5~eV^2$, the range of mass splittings that produce no significant oscillations over the Near Detector baseline.

hep-ex↗

arXiv2017

Constraints on Oscillation Parameters from $ν_e$ Appearance and $ν_μ$ Disappearance in NOvA

Results are reported from an improved measurement of $ν_μ\rightarrow ν_e$ transitions by the NOvA experiment. Using an exposure equivalent to $6.05\times10^{20}$ protons-on-target 33 $ν_e$ candidates were observed with a background of $8.2\pm0.8$ (syst.). Combined with the latest NOvA $ν_μ$ disappearance data and external constraints from reactor experiments on $\sin^22θ_{13}$, the hypothesis of inverted mass hierarchy with $θ_{23}$ in the lower octant is disfavored at greater than $93\%$ C.L. for all values of $δ_{CP}$.

hep-ex↗

arXiv2017

Measurement of the neutrino mixing angle $θ_{23}$ in NOvA

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of $6.05\times10^{20}$ protons-on-target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal mixing ($θ_{23} = π/4$). Assuming the normal mass hierarchy, we find $Δm^2 = (2.67 \pm 0.11)\times 10^{-3}$ eV$^2$ and $\sin^2 θ_{23}$ at the two statistically degenerate values $0.404^{+0.030}_{-0.022}$ and $0.624^{+0.022}_{-0.030}$, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6 $σ$ significance.

hep-ex↗