Conveners
Neutrino I
- Bei Zhou (Johns Hopkins University)
Searches for heavy neutral lepton production in K+ → e+N and K+ → +N decays using the data set collected by the NA62 experiment at CERN in 2016-18 are presented. Upper limits on the elements of the extended neutrino mixing matrix |Ue4|2 and |U4|2 are established at the levels of 10-9 and 10-8, respectively, improving on the earlier searches for heavy neutral lepton production and decays in...
The Majorana nature of neutrinos and whether lepton number symmetry is conserved are among the most pressing mysteries in physics today. This follows from their widespread implications for cosmology, nuclear physics, and particle physics. Along these lines, searches for the neutrinoless $\beta\beta$ ($0\nu\beta\beta$) decay mode of heavy nuclei are highly sensitive probes of these questions,...
If a heavy neutrino is discovered, determining its nature, i.e., whether it is a Dirac or a Majorana fermion, will be at the top of the list of the next questions to ask. A natural way to determine this is to analyze the particle's decays and to observe whether they violate lepton number. However, if the final state includes any light neutrinos, this is impossible. In that event, we may still...
Neutrinos are probably the most mysterious particles of the Standard Model. The mass hierarchy and oscillations, as well as the nature of their antiparticles, are currently being studied in experiments around the world. Moreover, in many models of the New Physics, baryon asymmetry or dark matter density in the universe are explained by introducing new species of neutrinos. Among others, heavy...
We examine the detection prospects for a long-lived biνo, a pseudo-Dirac bino which is responsible for neutrino masses, at the LHC and at dedicated long-lived particle detectors. The biνo arises in U(1)_R-symmetric supersymmetric models where the neutrino masses are generated through higher dimensional operators in an inverse seesaw mechanism. At the LHC the biνo is...
Heavy neutral leptons (HNLs) are among the simplest and most natural extensions of the Standard Model; they are widely expected in a range of more complicated dark sector models. At MeV scale masses, HNLs are typically very long lived and can be difficult to search for with laboratory experiments. In this talk I will discus how large volume detectors can search for decaying HNLs produced by...
We propose a supersymmetric extension of the minimal $U(1)_X$ model, along with a new $Z_2$-parity. One of the salient features of this model relates to how the $U(1)_X$ gauge symmetry is broken at the TeV scale. The running of the Majorana coupling of the $Z_2$-even right handed neutrino is shown to become large due to radiative corrections. As a result, this running causes the mass squared...
We study the phenomenology of the minimal $(2,2)$ inverse-seesaw model supplemented with Abelian flavour symmetries. To ensure maximal predictability, we establish the most restrictive flavour patterns which can be realised by those symmetries. This setup requires adding an extra scalar doublet and two complex scalar singlets to the Standard Model, paving the way to implement spontaneous CP...
