ICHEP 2016 Chicago

First measurement using NOvA detectors of neutrino oscillation parameters sin^{2}\theta_{23} and \Delta m^{2}_{32} (18' + 2')

6 Aug 2016, 14:00

20m

Chicago 6

Oral Presentation Neutrino Physics Neutrino Physics

Speaker

Keith Matera (Fermi National Accelerator Laboratory)

Description

This talk reports the first measurement using the NOvA detectors of
${\nu }_{\mu }$ disappearance in a ${\nu }_{\mu }$ beam. Oscillation parameters
$\mathrm{\Delta }{m}_{32}^2$ and ${\sin }^2{\theta }_{23}$ are measured as function
of the count and energy spectrum of ${\nu }_{\mu }$ interactions at a
Near and Far Detector, separated by a distance of $810\text{ km}$.
High-statistics Near Detector energy spectra are compared to Monte
Carlo predictions, and discrepancies used to perform a data-driven,
bin-by-bin ``Far/Near extrapolation'' correction to the predicted
Far Detector energy spectrum. The corrected spectrum is fit to data
in $\mathrm{\Delta }{m}_{32}^2$ and ${\sin }^2{\theta }_{23}$, marginalizing
over systematic uncertainties and the remaining oscillation parameters
(excepting ${\delta }_{CP}$, which is left unconstrained) to produce
best fit points and $90\mathrm{\%}$ confidence level contours. Systematic
uncertainties considered cover particle simulation, cross-sections,
detector calibration, and differences in exposure and performance
between the Far and Near Detectors. This analysis uses a 14 kton-equivalent
exposure of $2.74\times {10}^{20}$ protons-on-target from the Fermilab
NuMI beam. Assuming the normal neutrino mass hierarchy, we measure
$\mathrm{\Delta }{m}_{32}^2=({2.5}_{-0.18}^{+0.20})\times {10}^{-3}{\text{ eV}}^2$
and ${\sin }^2{\theta }_{23}$ in the range $0.38-0.65$, both at the
$68\mathrm{\%}$ confidence level, with two statistically-degenerate best fit
points at ${\sin }^2{\theta }_{23}=0.43$ and $0.60$. Results for the
inverted mass hierarchy are also presented.

Presentation materials

ICHEP_2016_NOvA_Numu_Matera_Aug6.pdf