No abstract

Abstract. We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved -cosmology, astrophysics, nuclear, and particle physics -in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrino Dark Matter arising from astrophysical observations, laboratory experiments, and theoretical considerations. In this context, we provide a balanced discourse on the possibly positive signal from X-ray observations. Another focus of the paper concerns the construction of particle physics models, aiming to explain how sterile neutrinos of keV-scale masses could arise in concrete settings beyond the Standard Model of elementary particle physics. The paper ends with an extensive review of current and future astrophysical and laboratory searches, highlighting new ideas and their experimental challenges, as well as future perspectives for the discovery of sterile neutrinos.

No abstract

No abstract

No abstract

A contribution from new gauge bosons in the SU(3) C ⊗SU(3) L ⊗U(1) N (3 -3 -1) models to the anomalous magnetic moments of the muon is calculated and numerically estimated. In the minimal 3 -3 -1 model, a lower bound on the bilepton mass at a value of 167 GeV is derived. For an expected precision(∼ 4 × 10 −10 ) of the BNL measurements the possible lower bounds on masses of the bileptons in the minimal version and in the version with right-handed neutrinos are around 940 GeV and 250 GeV, respectively.

From April to July 2018, a data sample at the peak energy of the resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be ( , where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II.

In a series of two papers all finite-dimensional irreducible representations and some indecomposible representations of the general linear Lie superalgebra gl(2/2) are constructed in a basis suitable for the decomposition gl(2/2)⊇gl(2)⊕gl(2). In this paper each induced gl(2/2) module W is represented as a direct sum of its irreducible gl(2)⊕gl(2) submodules Vi, 1≤i≤16. The basis Γ in W is chosen to consist of the union of all Γi, where Γi is an appropriate basis in each Vi. Expressions for the transformation of Γ under the action of the generators are written down for all induced and hence, also, for all typical gl(2/2) modules.