Related papers: Effective portals to heavy neutral leptons
We discuss the parameter space reach of future experiments searching for heavy neutral leptons (HNLs) at the GeV scale in terms of neutrino mass models with three HNL generations. We focus on two classes of models: Generic assumptions (such…
The existence of the tiny neutrino mass and the flavor mixing can be naturally explained by type-I Seesaw model which is probably the simplest extension of the Standard Model (SM) using Majorana type SM gauge singlet heavy Right Handed…
A search for heavy neutral leptons (HNLs) of Majorana or Dirac type using proton-proton collision data at $\sqrt{s}$ = 13 TeV is presented. The data were collected by the CMS experiment at the CERN LHC and correspond to an integrated…
Heavy Neutral Leptons (HNLs) have been an interesting topic for experimental particle physics in the past few years. A study has been performed within the framework of the multi-instrument DUNE near detector complex, specifically regarding…
Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) stands out as a pivotal process for precision tests of the Standard Model electroweak sector, investigations of neutrino properties, and searches for new physics (NP). Recent…
Effective field theory (EFT) approaches are widely used at the LHC, such that it is important to study their validity, and ease of matching to specific new physics models. In this paper, we consider an extension of the SM in which a top…
The gauge-invariant operators up to dimension six in the low-energy effective field theory below the electroweak scale are classified. There are 70 Hermitian dimension-five and 3631 Hermitian dimension-six operators that conserve baryon and…
We present an effective field theory describing the relevant interactions of the Standard Model with an electrically neutral particle that can account for the dark matter in the Universe. The possible mediators of these interactions are…
We consider extensions of the next-to-minimal supersymmetric model (NMSSM) in which the observed neutrino masses are described in terms of effective dimension six (or seven) rather than dimension five operators. All such operators respect…
We perform a model-independent analysis of top-philic New Physics scenarios, under the assumption that only effective operators involving top quarks are generated at tree level. Within the SMEFT framework, we derive indirect constraints on…
The Standard Model Effective Field Theory (SMEFT) is the parametrization chosen to interpret many modern measurements. We have recently discussed, building on the work of other groups, that its overall framework can be experimentally…
We propose new searches that exploit the unique signatures of decaying sterile neutrinos with masses below $M_W$ at the LHC, where they can be produced in rare decays of Standard Model gauge bosons. We show that for few-GeV-scale sterile…
We discuss neutrino masses from higher than d=5 effective operators in a supersymmetric framework, where we explicitly demonstrate which operators could be the leading contribution to neutrino mass in the MSSM and NMSSM. As an example, we…
The mass estimates of active and sterile (right-handed) neutrinos are considered at the phenomenological level using the seesaw mechanism. It is assumed that the neutrino mass values depend on three characteristic scales, and the sum of the…
We study ultra-violet completions for operators in standard model effective field theory extended with right-handed neutrinos ($N_R$SMEFT). Using a diagrammatic method, we generate systematically lists of possible tree-level completions…
We assess the ability of the Belle II experiment to probe the Dirac or Majorana nature of a massive right-handed neutrino (RHN) $N$ in the MeV to GeV mass range. We consider the production and decay of RHNs to proceed via new interactions…
The large hadron collider experiments have now reached the focus point region in which the scalar masses are multi-TeV. We study the parameter region of the focus point scenario which may realize a natural electroweak symmetry breaking…
We release FeynRules and UFO model files for the $\nu$SMEFT -- the effective field theory of the Standard Model extended with right-handed neutrinos, $N_R$. These model files include dimension-five and dimension-six Higgs-$N_R$ operators.…
The Standard Model Effective Field Theory (SMEFT) offers a systematic approach to study potential deviations from the Standard Model (SM) through higher-dimensional operators that encapsulate new physics effects. In this work, we analyze…
We show that in a class of non-supersymmetric left-right extensions of the Standard Model (SM), the lightest right-handed neutrino (RHN) can play the role of thermal Dark Matter (DM) in the Universe for a wide mass range from TeV to PeV.…