Abstract: We present a detailed analysis of the spectral data of Borexino Phase II, with the aim of exploiting its full potential to constrain scenarios beyond the Standard Model. In particular, we quantify the constraints imposed on neutrino magnetic moments, neutrino non-standard interactions, and several simplified models with light scalar, pseudoscalar or vector mediators. Our analysis shows perfect agreement with those performed by the collaboration on neutrino magnetic moments and neutrino non-standard interactions in the same restricted cases and expands beyond those, stressing the interplay between flavour oscillations and flavour non-diagonal interaction effects for the correct evaluation of the event rates. For simplified models with light mediators we show the power of the spectral data to obtain robust limits beyond those previously estimated in the literature.

Abstract: We present an approach that allows one to obtain information on the compositeness of molecular states from combined information of the scattering length of the hadronic components, the effective range, and the binding energy. We consider explicitly the range of the interaction in the formalism and show it to be extremely important to improve on the formula of Weinberg obtained in the limit of very small binding and zero range interaction. The method allows obtaining good information also in cases where the binding is not small. We explicitly apply it to the case of the deuteron and the D-s0* (2317) and D-s1* (2460) states and determine simultaneously the value of the compositeness within a certain range, as well as get qualitative information on the range of the interaction.

Abstract: This article presents the results of two studies of Higgs boson properties using the WW*(-> e nu μnu)jj final state, based on a dataset corresponding to 36.1fb(-1) of root s = 13 TeV proton-proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon-gluon fusion and constrains the CP properties of the effective Higgs-gluon interaction. Using angular distributions and the overall rate, a value of tan (alpha) = 0.0 +/- 0.4(stat.) +/- 0.3(syst.) is obtained for the tangent of the mixing angle for CP-even and CP-odd contributions. The second study exploits the vector-boson fusion production mechanism to probe the Higgs boson couplings to longitudinally and transversely polarised W and Z bosons in both the production and the decay of the Higgs boson; these couplings have not been directly constrained previously. The polarisation-dependent coupling-strength scale factors are defined as the ratios of the measured polarisation-dependent coupling strengths to those predicted by the Standard Model, and are determined using rate and kinematic information to be a(L) = 0.91(-0.18)(+0.10)(stat.)(-0.17)(+0.09)(syst.) and a(T) = 1.2 +/- 0.4(stat.)(-0.3)(+0.2)(syst.). These coupling strengths are translated into pseudo-observables, resulting in kappa(VV) = 0.91(-0.18)(+0.10)(stat.)(-0.17)(+0.09)(syst.) and epsilon(VV) = 0.13(-0.20)(+0.28)(stat.)(-0.10)(+0.08)(syst.). All results are consistent with the Standard Model predictions.

Abstract: The metric-affine bumblebee model in the presence of fermionic matter minimally coupled to the connection is studied. We show that the model admits an Einstein frame representation in which the matter sector is described by a non-minimal Dirac action without any analogy in the literature. Such non-minimal terms involve unconventional couplings between the bumblebee and the fermion field. We then rewrite the quadratic fermion action in the Einstein frame in the basis of 16 Dirac matrices in order to identify the coefficients for Lorentz/CPT violation in all orders of the non-minimal coupling xi. The exact result for the fermionic determinant in the Einstein frame, including all orders in xi, is also provided. We demonstrate that the axial contributions are at least of second order in the perturbative expansion of xi. Furthermore, we compute the one-loop effective potential within the weak field approximation.

Abstract: We propose a minimal model based on lepton number symmetry (and violation), to address a common origin of baryon asymmetry, dark matter and neutrino mass generation. The model consists of a vectorlike fermion to constitute the dark sector, three right-handed neutrinos (RHNs) to dictate leptogenesis and neutrino mass, while an additional complex scalar is assumed to be present in the early Universe the decay of which produces both dark matter and RHNs via lepton number violating and lepton number conserving interactions respectively. Interestingly, the presence of the same scalar helps in making the electroweak vacuum stable until the Planck scale. The unnatural largeness and smallness of the parameters required to describe correct experimental limits are attributed to lepton number violation. The allowed parameter space of the model is illustrated via a numerical scan.