Abstract: Non-standard interactions of neutrinos arising in many theories beyond the Standard Model can significantly alter matter effects in atmospheric neutrino propagation through the Earth. In this paper, a search for deviations from the prediction of the standard 3-flavour atmospheric neutrino oscillations using the data taken by the ANTARES neutrino telescope is presented. Ten years of atmospheric neutrino data collected from 2007 to 2016, with reconstructed energies in the range from similar to 16 GeV to 100 GeV, have been analysed. A log-likelihood ratio test of the dimensionless coefficients epsilon(mu tau) and epsilon(tau tau) – epsilon(mu mu) does not provide clear evidence of deviations from standard interactions. For normal neutrino mass ordering, the combined fit of both coefficients yields a value 1.7 sigma away from the null result. However, the 68% and 95% confidence level intervals for epsilon(mu tau) and epsilon(tau tau) – epsilon(mu mu), respectively, contain the null value. Best fit values, one standard deviation errors and bounds at the 90% confidence level for these coefficients are given for both normal and inverted mass orderings. The constraint on epsilon(mu tau) is among the most stringent to date and it further restrains the strength of possible non-standard interactions in the μ- tau sector.

Abstract: Neutron capture reaction cross sections on Ge-74 are of importance to determine Ge-74 production during the astrophysical slow neutron capture process. We present new resonance data on Ge-74(n, gamma ) reactions below 70 keV neutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment.

Abstract: Neutrino experiments lie at the edge of the intensity frontier and therefore can be exploited to search for new light particles weakly coupled to the visible sector. In this work we derive new constraints on axion-like particles (ALPs) using data from the MicroBooNE experiment, from a search for e(+)e(-) pairs pointing in the direction of the NuMI absorber. In particular, we consider the addition of higher-dimensional effective operators coupling the ALP to the electroweak gauge bosons. These would induce K -> pi a from kaon decay at rest in the NuMI absorber, as well as ALP decays into pairs of leptons or photons. We discuss in detail and compare various results obtained for the decay width K -> pi a in previous literature. For the operator involving the Higgs, MicroBooNE already sets competitive bounds (comparable to those of NA62) for ALP masses between 100 and 200 MeV. We also compute the expected sensitivities from the full NuMI dataset recorded at MicroBooNE. Our results show that a search for a -> gamma gamma signal may be able to improve over current constraints from beam-dump experiments on the operator involving the ALP coupling to the W.

Abstract: Motivated by a possible interplay between the mechanism of dynamical symmetry breaking and the seesaw mechanism for generating fermion masses, we present a scale-invariant model that extends the gauge symmetry of the Standard Model electroweak sector to SU(3)L (R) U(1)X (R) U(1)N, with a built-in B – L symmetry. The model is based on the symmetry structure of the known 3-3-1 models and, thus, it relates the number of the three observed fermion generations with the cancellation of gauge anomalies. Symmetry breaking is triggered via the Coleman-Weinberg mechanism, taking into account a minimal set of scalar field multiplets. We establish the stability conditions for the tree-level scalar potential imposing the copositivity criteria and use the method of Gildener-Weinberg for computing the one-loop effective potential when one has multiple scalar fields. With the addition of vectorial fermions, getting their mass mainly through the vacuum expectation value of scalar singlets at 103 TeV, the B – L symmetry leads to textures for the fermion mass matrices, allowing seesaw mechanisms for neutrinos and quarks to take place. In particular, these mechanisms could partly explain the mass hierarchies of the quarks. Once the breakdown of the SU(3)L symmetry is supposed to occur around 10 TeV, the model also predicts new particles with TeV-scale masses, such as a neutral scalar H1, a charged scalar HI, and the gauge bosons Z', W'I, and Y0, that could be searched with the high-luminosity LHC.

Abstract: Minimal dark energy models, described by the same number of free parameters of the standard cosmological model with cold dark matter plus a cosmological constant to parametrize the dark energy component, constitute very appealing scenarios which may solve long-standing, pending tensions. On the one hand, they alleviate significantly the tension between cosmological observations and the presence of one sterile neutrino motivated by the short-baseline anomalies: we obtain a 95% CL cosmological bound on the mass of a fully thermalized fourth sterile neutrino (N-eff = 4) equal to m(s) < 0.65(1.3) eV within the Phenomenologically Emergent Dark Energy (PEDE) and Vacuum Metamorphosis (VM) scenarios under consideration. Interestingly, these limits are in agreement with the observations at short-baseline experiments, and the PEDE scenario is favored with respect to the Lambda CDM case when the full data combination is considered. On the other hand, the Hubble tension is satisfactorily solved in almost all the minimal dark energy schemes explored here. These phenomenological scenarios may therefore shed light on differences arising from near and far Universe probes, and also on discrepancies between cosmological and laboratory sterile neutrino searches.