Interactions of cosmic ray protons, atomic nuclei, and electrons in the interstellar medium in the inner part of the Milky Way produce a γ-ray flux from the Galactic Ridge. If the γ-ray emission is ...dominated by proton and nuclei interactions, a neutrino flux comparable to the γ-ray flux is expected from the same sky region.
Data collected by the ANTARES neutrino telescope are used to constrain the neutrino flux from the Galactic Ridge in the 1-100 TeV energy range. Neutrino events reconstructed both as tracks and showers are considered in the analysis and the selection is optimized for the search of an excess in the region |l|<30°, |b|<2°. The expected background in the search region is estimated using an off-zone region with similar sky coverage. Neutrino signal originating from a power-law spectrum with spectral index ranging from Γν=1 to 4 is simulated in both channels. The observed energy distributions are fitted to constrain the neutrino emission from the Ridge.
The energy distributions in the signal region are inconsistent with the background expectation at ∼96% confidence level. The mild excess over the background is consistent with a neutrino flux with a power law with a spectral index 2.45−0.34+0.22 and a flux normalization dNνdEν=4.0−2.0+2.7×10−16 GeV−1cm−2s−1sr−1 at 40 TeV reference energy. Such flux is consistent with the expected neutrino signal if the bulk of the observed γ-ray flux from the Galactic Ridge originates from interactions of cosmic ray protons and nuclei with a power-law spectrum extending well into the PeV energy range.
The T2K experiment is a long-baseline accelerator neutrino experiment using a near detector complex ND280 and a far detector, Super-Kamiokande. Neutrino interactions are detected by Cherenkov light ...in Super-Kamiokande in order to measure neutrino oscillation parameters. The accuracy of the oscillation parameter measurements depends on our knowledge of neutrino interactions, the neutrino flux and the detector response. ND280 is composed of a tracker and several sub-detectors designed to characterise the neutrino beam before oscillation, which allow us to constrain the uncertainties on the neutrino interaction and the accelerator flux models. In this talk we present the result of a fit on the ND280 data, as well as a study of the robustness of the fit to the choice of neutrino interaction model. The constraint obtained on the oscillation parameters is also discussed.
T2K is a long-baseline neutrino oscillation experiment taking data since 2010. A neutrino beam is produced at the J-PARC accelerator in Japan and is sampled at a Near Detector complex 280 m from the ...neutrino production point and at the far detector, Super-Kamiokande, located 295 km from the source. Beams predominantly composed of muon neutrinos or muon anti-neutrinos have been produced by changing the currents in the magnetic focusing horns. This presentation will show the most recent T2K oscillation results obtained from a combined analysis of the entire available data set in the muon neutrino and muon anti-neutrino disappearance channels, and in the electron neutrino and electron anti-neutrino appearance channels. The data cover runs 1 to 8 (2010 to 2017) and consist of \(7.252 \cdot 10^{20}\) POT in neutrino mode and \(7.531 \cdot 10^{20}\) POT in antineutrino mode. Using these data, we measure four oscillations parameters: \(\sin^2 \theta_{23}\), \(\sin^2 \theta_{13}\), \(\Delta m_{32}^2\) and \(\delta_{CP}\). The analysis excludes CP-conservation in the neutrino sector at 90\% C.L.
We use the gravitational wave (GW) events GW170817 and GW190521, together with their proposed electromagnetic counterparts, to constrain cosmological parameters and theories of gravity beyond General ...Relativity (GR). In particular we consider models with a time-varying Planck mass, large extra-dimensions, and a phenomenological parametrization covering several beyond-GR theories. In all three cases, this introduces a friction term into the GW propagation equation, effectively modifying the GW luminosity distance. We set constraints on \(\Lambda\)CDM parameters and GR deviation parameters using two sets of priors on the Hubble constant and matter energy density. With priors set to the measured Planck's mission values, we find that with the inclusion of GW190521, the two GR deviation parameters constraints improves by a factor \(\sim 10\), we report a number of spacetime dimensions compatible with \(4\) with an precision of \(2.5\%\) (at 95\% CL) and an upper limit to the variation of Netwon's constant at the epoch of GW170817 \(<20\%\). With wide priors on the Hubble constant and matter energy density, we show that it is still possible to constrain the \(\Lambda\)CDM parameters and GR deviation parameters conjointly from GW170817 and GW190521 obtaining constraints on GR deviation parameters which are a factor \(2-6\) worse than the results using restricted priors on \(\Lambda\)CDM parameters.
High-significance evidences of the existence of a high-energy diffuse flux of cosmic neutrinos have emerged in the last decade from several observations by the IceCube Collaboration. The ANTARES ...neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this article. This final analysis did not provide a statistically significant observation of the cosmic diffuse flux: this is converted into limits on the properties of the cosmic neutrino spectrum. In particular, given the sensitivity of the ANTARES neutrino telescope between 1 and 50 TeV, constraints on single-power-law hypotheses are derived for the cosmic diffuse flux below 20 TeV.
Position calibration in the deep sea is typically done by means of acoustic multilateration using three or more acoustic emitters installed at known positions. Rather than using hydrophones as ...receivers that are exposed to the ambient pressure, the sound signals can be coupled to piezo ceramics glued to the inside of existing containers for electronics or measuring instruments of a deep sea infrastructure. The ANTARES neutrino telescope operated from 2006 until 2022 in the Mediterranean Sea at a depth exceeding 2000m. It comprised nearly 900 glass spheres with 432mm diameter and 15mm thickness, equipped with photomultiplier tubes to detect Cherenkov light from tracks of charged elementary particles. In an experimental setup within ANTARES, piezo sensors have been glued to the inside of such - otherwise empty - glass spheres. These sensors recorded signals from acoustic emitters with frequencies from 46545 to 60235Hz. Two waves propagating through the glass sphere are found as a result of the excitation by the waves in the water. These can be qualitatively associated with symmetric and asymmetric Lamb-like waves of zeroth order: a fast (early) one with \(v_e \approx 5\)mm/\(\mu\)s and a slow (late) one with \(v_\ell \approx 2\)mm/\(\mu\)s. Taking these findings into account improves the accuracy of the position calibration. The results can be transferred to the KM3NeT neutrino telescope, currently under construction at multiple sites in the Mediterranean Sea, for which the concept of piezo sensors glued to the inside of glass spheres has been adapted for monitoring the positions of the photomultiplier tubes.
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