Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in the Universe and provide a dark matter candidate. The SHiP experiment will be able to search for HNLs produced in decays of heavy mesons and travelling distances ranging between $$ \mathcal{O} $$ O (50 m) and tens of kilometers before decaying. We present the sensitivity of the SHiP experiment to a number of HNL’s benchmark models and provide a way to calculate the SHiP’s sensitivity to HNLs for arbitrary patterns of flavour mixings. The corresponding tools and data files are also made publicly available.

SND@LHC is a compact and stand-alone experiment designed to perform measurements with neutrinos produced at the LHC in the pseudo-rapidity region of 7.2 < η < 8.4. The experiment is located 480 m downstream of the ATLAS interaction point, in the TI18 tunnel. The detector is composed of a hybrid system based on an 830 kg target made of tungsten plates, interleaved with emulsion and electronic trackers, also acting as an electromagnetic calorimeter, and followed by a hadronic calorimeter and a muon identification system. The detector is able to distinguish interactions of all three neutrino flavours, which allows probing the physics of heavy flavour production at the LHC in the very forward region. This region is of particular interest for future circular colliders and for very high energy astrophysical neutrino experiments. The detector is also able to search for the scattering of Feebly Interacting Particles. In its first phase, the detector is ready to operate throughout LHC Run 3 and collect a total of 250 fb^-1.

The OPERA experiment was designed to study ${\nu }_{\mu }\to {\nu }_{\tau }$ oscillations in the appearance mode in the CERN to Gran Sasso Neutrino beam (CNGS). In this Letter, we report the final analysis of the full data sample collected between 2008 and 2012, corresponding to $17.97\times {10}^{19}$ protons on target. Selection criteria looser than in previous analyses have produced ten ${\nu }_{\tau }$ candidate events, thus reducing the statistical uncertainty in the measurement of the oscillation parameters and of ${\nu }_{\tau }$ properties. A multivariate approach for event identification has been applied to the candidate events and the discovery of ${\nu }_{\tau }$ appearance is confirmed with an improved significance level of $6.1\sigma$. $|\mathrm{\Delta }{m}_{32}^2|$ has been measured, in appearance mode, with an accuracy of 20%. The measurement of the ${\nu }_{\tau }$ charged-current cross section, for the first time with a negligible contamination from ${\overline{\nu }}_{\tau }$, and the first direct evidence for the ${\nu }_{\tau }$ lepton number are also reported.

We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at $\sqrt{s}=13.6\mathrm{TeV}$ collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of $36.8{\mathrm{fb}}^{-1}$. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of $7.2<\eta <8.4$, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ${\nu }_{\mu }$ interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ${\nu }_{\mu }$ signal.

Muography consists in observing the differential absorption of muons – elementary particles produced through cosmic-ray interactions in the Earth atmosphere – going through the volcano and can attain a spatial resolution of tens of meters. We present here the first experiment of nuclear emulsion muography at the Stromboli volcano. Muons have been recorded during a period of five months by a detector of 0.96 m² area. The emulsion films were prepared at the Gran Sasso underground laboratory and were analyzed at Napoli, Salerno and Tokyo scanning laboratories. Our results highlight a significant low-density zone at the summit of the volcano with density contrast of 30–40% with respect to bedrock. The structural setting of this part of the volcanic edifice controls the eruptive dynamics and the stability of the “Sciara del Fuoco” slope, which is affected by recurrent tsunamigenic landslides. Periodical imaging of the summit of the Stromboli volcano such as that provided by muography can become a useful method for studying the evolution of the internal structure of the volcanic edifice.