arXiv subjects

D. Coplowe

Publications and source records attributed to D. Coplowe.

44 records · Page 3Linked to original sources

arXiv2017

First combined analysis of neutrino and antineutrino oscillations at T2K

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beam. The data include all runs from Jan 2010 to May 2016 and comprise $7.482\times10^{20}$,protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 $μ$-like events, and $7.471\times10^{20}$,protons on target in antineutrino mode which yielded 4 e-like and 66 $μ$-like events. Reactor measurements of $\sin^{2}2θ_{13}$ have been used as an additional constraint. The one-dimensional confidence interval at 90% for $δ_{CP}$ spans the range ($-3.13$, $-0.39$) for normal mass ordering. The CP conservation hypothesis ($δ_{CP}=0,π$) is excluded at 90% C.L.

hep-ex↗

arXiv2016

First Measurement of the Muon Neutrino Charged Current Single Pion Production Cross Section on Water with the T2K Near Detector

The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\sim}0.8$ GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{π^+}>200$MeV/c, $p_{μ^-}>200$MeV/c, $\cos θ_{π^+}>0.3$ and $\cos θ_{μ^-}>0.3$. The total flux integrated $ν_μ$ charged current single positive pion production cross section on water in the restricted phase-space is measured to be $\langleσ\rangle_ϕ=4.25\pm0.48 (\mathrm{stat})\pm1.56 (\mathrm{syst})\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$. The total cross section is consistent with the NEUT prediction ($5.03\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$) and 2$σ$ lower than the GENIE prediction ($7.68\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$). The differential cross sections are in good agreement with the NEUT generator. The GENIE simulation reproduces well the shapes of the distributions, but over-estimates the overall cross section normalization.

hep-ex↗

arXiv2016

Measurement of coherent $π^{+}$ production in low energy neutrino-Carbon scattering

We report the first measurement of the flux-averaged cross section for charged current coherent $π^{+}$ production on carbon for neutrino energies less than 1.5 GeV to a restricted final state phase space region in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso {\it et al.}, the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. This results contradicts the null results reported by K2K and SciBooNE in a similar neutrino energy region.

hep-ex↗

arXiv2016

Proposal for an Extended Run of T2K to $20\times10^{21}$ POT

Recent measurements by the T2K neutrino oscillation experiment indicate that CP violation in neutrino mixing may be observed in the future by long-baseline neutrino oscillation experiments. We propose an extension to the currently approved T2K running from $7.8\times 10^{21}~\mbox{POT}$ to $20\times 10^{21}~\mbox{POT}$, aiming at initial observation of CP violation with 3$\,σ$ or higher significance for the case of maximum CP violation. The program also contains a measurement of mixing parameters, $θ_{23}$ and $Δm^2_{32}$, with a precision of 1.7$^\circ$ or better and 1%, respectively. With accelerator and beamline upgrades, as well as analysis improvements, this program would occur before the next generation of long-baseline neutrino oscillation experiments that are expected to start operation in 2026.

hep-ex↗

arXiv2016

Sensitivity of the T2K accelerator-based neutrino experiment with an Extended run to $20\times10^{21}$ POT

Recent measurements at the T2K experiment indicate that CP violation in neutrino mixing may be observed in the future by long-baseline neutrino oscillation experiments. We explore the physics program of an extension to the currently approved T2K running of $7.8\times 10^{21}$ protons-on-target to $20\times 10^{21}$ protons-on-target,aiming at initial observation of CP violation with 3$\,σ$ or higher significance for the case of maximum CP violation. With accelerator and beam line upgrades, as well as analysis improvements, this program would occur before the next generation of long-baseline neutrino oscillation experiments that are expected to start operation in 2026.

hep-ex↗

arXiv2016

Measurement of nuclear effects in neutrino interactions with minimal dependence on neutrino energy

We present a phenomenological study of nuclear effects in neutrino charged-current interactions, using transverse kinematic imbalances in exclusive measurements. Novel observables with minimal dependence on neutrino energy are proposed to study quasielastic scattering, and especially resonance production. They should be able to provide direct constraints on nuclear effects in neutrino- and antineutrino-nucleus interactions.

nucl-th↗

arXiv2016

Isolating neutrino interactions on hydrogen in composite nuclear targets using the T2K Near Detector

An analysis technique for isolating neutrino interactions on hydrogen, from a target containing a mixture of different nuclei, would provide numerous benefits. Namely, hydrogen is free of nuclear effects and enables better reconstruction of the neutrino energy spectra; key for neutrino oscillation experiments. Presented using Monte Carlo simulations of the ND280 near detector is the status of such a measurement on v-H resonance production by the T2K experiment.

hep-ex↗

arXiv2015

Reconstruction of Energy Spectra of Neutrino Beams Independent of Nuclear Effects

We propose a new technique which enables an event-by-event selection of neutrino-hydrogen interactions in multi-nuclear targets and thereby allows application of hydrogen as targets in experiments with neutrino beams without involving cryogenics or high pressure hydrogen gas. This technique could significantly improve the reconstruction of the neutrino energy spectra. Since it allows a separation between hydrogen and the accompanying nuclei, this technique also enables us to measure nuclear effects in neutrino interactions directly.

hep-ex↗