Study of tau neutrinos and non-unitary neutrino mixing with the first six detection units of KM3NeT/ORCA

Aiello, S.; Albert, A.; Alhebsi, A.R.; Alshamsi, M.; Alves Garre, S.; Ambrosone, A.; Ameli, F.; Andre, M.; Aphecetche, L.; Ardid, M.

Study of tau neutrinos and non-unitary neutrino mixing with the first six detection units of KM3NeT/ORCA

KM3NeT

Collaboration

Feb 3, 2025

30 pages

e-Print:

2502.01443 [hep-ex]

Experiments:

KM3NeT

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Abstract: (arXiv)

Oscillations of atmospheric muon and electron neutrinos produce tau neutrinos with energies in the GeV range, which can be observed by the ORCA detector of the KM3NeT neutrino telescope in the Mediterranean Sea. First measurements with ORCA6, an early subarray corresponding to about 5

\%

of the final detector, are presented. A sample of 5828 neutrino candidates has been selected from the analysed exposure of 433 kton-years. The

\nu_\tau

normalisation, defined as the ratio between the number of observed and expected tau neutrino events, is measured to be

S_\tau = 0.48^{+0.5}_{-0.33}

. This translates into a

\nu_\tau

charged-current cross section measurement of

\sigma_{\tau}^{\text{meas}} = (2.5 ^{+2.6}_{-1.8}) \times 10^{-38}

cm

^{2}

nucleon

^{-1}

at the median

\nu_\tau

energy of 20.3 GeV. The result is consistent with the measurements of other experiments. In addition, the current limit on the non-unitarity parameter affecting the

\tau

-row of the neutrino mixing matrix was improved, with

\alpha_{33}>

0.95 at the 95

\%

confidence level.

Note:

25 pages, 8 figures •
Prepared for submission to JHEP

References(0)

Figures(8)

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