Conveners
Neutrino Physics: Solar/Atm/SN
- Masashi Yokoyama
Neutrino Physics: Sterile (I)
- Sunny Seo (IBS)
Neutrino Physics: Reactor
- Sunny Seo
Neutrino Physics: Sterile (II)
- Sunny Seo
Neutrino Physics: LBL (I)
- Masashi Yokoyama
Neutrino Physics: LBL (II)
- Ken Long
Neutrino Physics: Theory (I)
- Serguey Petcov
Neutrino Physics: DBD (I)
- Liangjian Wen
Neutrino Physics: LBL (III)
- Chang Kee Jung
Neutrino Physics: Theory (II)
- Danny Marfatia (University of Hawaii)
Neutrino Physics: DBD (II)
- Liangjian Wen
Borexino is running at the “Laboratori del Gran Sasso” in Italy since 2007. Its technical distinctive feature is the unprecedented ultralow background of the inner scintillating core, which is the foundation for the outstanding achievements accumulated by this experiment.
In the present talk, after recalling the main features of the detector, the impressive solar data gathered so far by...
The next stage of the highly successful Super-Kamiokande experiment is to load gadolinium (Gd) sulphate at 0.2% by mass. Gadolinium has a very large cross section for thermal neutron capture, which produces a cascade of gamma rays totalling 8 MeV. This is much easier to detect than the 2.2 MeV gamma ray from neutron capture on hydrogen that is currently used for neutron tagging. By tagging...
The Super-Kamiokande detector (SuperK) has been running since 1996. In addition to the discovery of neutrino oscillations which led to the Nobel Price in Physics in 2015, it has delivered many important results: the best proton lifetime and Diffuse Supernova Neutrino Background limits to cite two examples. With an extensive physics programme and a long and successful past, the SuperK...
After the initial observation of neutrino oscillations using atmospheric neutrinos, considerable progress has been made in the understanding of the mixing paradigm using long-baseline and reactor neutrinos. Despite these successes, there are several open questions remaining, including the ordering of the neutrino masses, the octant of the atmospheric mixing angle, and whether or not neutrino...
Hyper-Kamiokande (Hyper-K) is a proposed next generation underground large water Cherenkov detector with 260 kton of water and 40% photo coverage.
With about 10 times larger fiducial volume than Super-Kamiokande, the sensitivities for astrophysical neutrinos, like solar neutrinos or supernova neutrinos, will be greatly improved in Hyper-K. In this presentation, we will discuss the physics...
ORCA is the low-energy detector of KM3NeT, the next generation underwater Cherenkov neutrino observatory in the Mediterranean Sea. With ORCA, the primary goal is to resolve the long-standing unsolved question of whether the neutrino mass ordering is normal or inverted, by measuring matter oscillation effects with atmospheric neutrinos. The ORCA design foresees a dense configuration of KM3NeT...
DANSS is a solid state scintillation detector of reactor antineutrino,
placed just below 3.1 GW industrial light water reactor of Kalininskaya Nuclear
Power Plant about 350 km NW from Moscow. A cubic meter sensitive volume of
the detector is formed by 2500 scintillator strips with individual SiPM
readout. Groups of 50 strips are also readout by conventional PMTs.
Reactor antineutrinos are...
The NEOS experiment has successfully measured the reactor antineutrino energy spectrum at 24 m distance from Hanbit reactor unit 5 for 180 days of reactor operation and constrained the active-to-sterile oscillation parameters. An extended measurement for a whole burnup cycle by the NEOS Phase-II will be a unique probe for the dependence of the reactor antineutrino flux and spectrum on the fuel...
PROSPECT (Precision Reactor Oscillation and Spectrum) is a short-baseline reactor antineutrino experiment. PROSPECT consists of a segmented 4-ton $^{6}$Li liquid scintillator antineutrino detector that will precisely measure the $^{235}{U}$ fission antineutrino spectrum from the High-Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). PROSPECT's high statistics and high...
In the recent period, re-evaluations of the neutrino flux and spectrum emitted by nuclear reactors have led to the so-called Reactor Antineutrino Anomaly (RAA). This anomaly could be caused by the existence of a light sterile neutrino eigenstate participating in the neutrino oscillation phenomenon. This implies the presence of a fourth mass eigenstate, while global fits of reactor experimental...
Several anomalies in the neutrino sector are pointing towards the existence of a new (sterile) neutrino state with a mass around 1 eV. The SoLid experiment is located at the SCK•CEN BR2 research reactor in Belgium and will investigate this possibility. Using the large flux of anti-neutrino generated in the reactor, it will collect a high statistics sample of Inverse Beta Decay (IBD) events....
In its original 2002-2007 run, MiniBooNE observed an anomalous and yet-unexplained excess of electromagnetic events at low energy neutrino energies. This observation is one of several that has pushed the discussion and search for sterile neutrinos. Since 2016, MiniBooNE has been collecting new neutrino-mode data, doubling the statistics from the original 2002-2007 run. We will revisit the...
The Reactor Experiment for Neutrino Oscillation (RENO) has been taking reactor antineutrinos data from the six reactors at Hanbit Nuclear Power Plant in Korea using two identical near and far detectors since August, 2011. The samllest neutrino mixing angle θ_13 has been successfully measured by observing the disappearance of reactor antineutrinos. In 2016, RENO has published an updated value...
The Daya Bay experiment is designed to precisely measure the reactor electron-antineutrino oscillation utilizing eight functionally identical detectors placed at three underground experiment halls. The antineutrinos are generated from six reactor cores distributed with baselines from 500 m to 1600 m. In 2012, the Daya Bay experiment observed the reactor antineutrino disappearance and presented...
The Daya Bay Reactor Neutrino Experiment consists of eight functionally identical detectors placed underground at different baselines from six 2.9 $\mathrm{GW_{th}}$ reactor cores. Since Dec. 2011, the experiment has collected more than 2.2 million inverse beta decay (IBD) candidates to date, enabling a precision measurement of the absolute reactor antineutrino flux and spectrum, and their...
Additional generations of neutrinos that do not participate in standard V-A interactions - hence called “sterile” - arise in many extensions of the Standard Model. The existence of light sterile neutrino, with masses at eV or sub-eV scale, could explain several anomalies in short neutrino oscillation experiments as well as discrepancy in cosmological measurements of the Hubble parameter. I...
The Jiangmen Underground Neutrino Observatory (JUNO) is a reactor-based neutrino oscillation experiment primarily aiming at resolving neutrino mass hierarchy (MH) located in South China. There are a few key elements in designing the JUNO detector in order to resolve the neutrino mass hierarchy with high confidence levels. To get sufficient statistics within a reasonable amount of time, JUNO...
The importance of a good model for the $\gamma$-ray energy spectrum from the radiative thermal neutron capture on Gadolinium (Gd) is specially increased in the present era of Gd-enhanced $\bar{\nu}_e$-search detectors. Its an essential prerequisite for MC studies to evaluate the neutron tagging efficiency, in order to enhance signal sensitivity in the Gd-loaded $\bar{\nu}_e$-search detectors....
I will describe nonstandard matter effects in the next generation long-baseline experiments, DUNE, T2HK and T2HKK.
The Fermilab Short-Baseline Neutrino (SBN) program, with three liquid argon time projection chamber (LAr-TPC) detectors located along the Booster Neutrino Beam, presents a rich physics and R&D opportunity. SBN will perform sensitive searches for neutrino oscillations in both appearance and disappearance channels at the 1 eV^2 mass- splitting scale, thereby testing the sterile neutrino...
SBND (Short-Baseline Near Detector) is a 112-ton liquid argon TPC neutrino detector under construction in the Fermilab Booster Neutrino Beam. Together with MicroBooNE and ICARUS-T600 detectors, SBND will search for short baseline neutrino oscillations in the 1 eV2 mass range. SBND will also perform detailed studies of the physics of neutrino-argon interactions, thanks to a data sample of...
MicroBooNE is a large 170-ton liquid-argon time projection chamber (LArTPC) neutrino experiment located on the Booster neutrino beamline at Fermilab. The experiment first started collecting neutrino data in October 2015. The detector serves as a next step in a phased program towards the construction of massive kiloton scale LArTPC detectors for future long-baseline neutrino physics (DUNE) and...
The MicroBooNE experiment has been taking data in a LArTPC detector at Fermilab since late 2015. This talk will present initial cross-section results from MicroBooNE, alongside our progress on a short-baseline neutrino oscillation analysis in the region of the MiniBooNE low-energy excess. These results will be discussed in the wider context of MicroBooNE's long-term physics goals of neutrino...
The JSNS$^2$ experiment aims to search for the existence of neutrino oscillations with $\Delta {\rm m}^2$ near 1 eV$^2$ at the J-PARC Materials and Life Science Experimental Facility. A 1 MW proton beam (3 GeV) incident on a mercury target produces an intense neutrino beam from muon decay at rest ($\mu^{+} \rightarrow e^{+} + \bar{\nu}_{\mu} + \nu_{e}$). The oscillation to be searched for is...
T2K is a long baseline accelerator neutrino experiment in Japan which studies
neutrino oscillations with a narrow-band muon neutrino beam peaked at 0.6 GeV.
The large water Cherenkov detector Super-Kamiokande (SK) located 295 km away
from the proton target acts as a far detector and provides high quality
samples for oscillation analysis. In the present study the T2K setup is used
to search for...
Heavy Neutral Leptons (HNLs, heavy neutrinos) with masses below the electroweak
scale are introduced in some extensions of the Standard Model to address
consistently such effects as neutrino oscillations, light neutrino masses,
dark matter and baryon asymmetry. In the mass range below 500 MeV/$c^2$ these
heavy neutrinos can be produced in pion or kaon decays, and further decay
themselves into...
Searches for heavy neutral lepton (HNL) production in charged kaon
decays using the data collected by the NA62 experiment at CERN are
reported. Upper limits are established on the elements of the extended
neutrino mixing matrix for heavy neutral lepton mass in the range
130-450 MeV, improving on the results from previous HNL production
searches. The status and prospects of searches for lepton...
ENUBET has been designed to monitor lepton production in the decay tunnel of neutrino beams at single particle level and to provide a 1% measurement of the neutrino flux at source. In particular, the three body semileptonic decay of kaons monitored by large angle positron production offers a fully controlled nu_e source at the GeV scale for a new generation of short baseline experiments. The...
At the CERN SPS, the DsTau project has been proposed to study tau-neutrino production aiming at providing important information for future $\nu_\tau$ measurements. Precise measurement of the $\nu_\tau$ cross section would enable a search for new physics effects in $\nu_\tau$-nucleon CC interactions. It also has practical implications for neutrino oscillation experiments. The dominant source of...
The uncertainty in the flux of neutrino beams is dominated by our understanding of both the primary interactions of protons and the secondary interactions of protons, kaons and pions with target and beamline material. Hadron production measurements from a comprehensive set of interactions will allow modern neutrino experiments to make more precise neutrino cross section and oscillation...
The nuSTORM facility will provide \nu_e and \nu_\mu beams from the decay of low energy muons confined within a storage ring. The instrumentation of the ring, combined with the excellent knowledge of muon decay, will make it possible to determine the neutrino flux at the %-level or better. The neutrino and anti-neutrino event rates are such that the nuSTORM facility serving a suite of near...
IsoDAR is a compact, accelerator-based source for anti-electron neutrinos produced through $^{8}$Li decay. When paired with a large scintillator-based detector, IsoDAR allows for a high-precision investigation of the reactor and source-based neutrino oscillation anomalies. This talk will discuss this physics, as well as other beyond Standard Model precision measurements that can be performed....
SHIP is a new general purpose fixed target facility, whose Technical Proposal has been recently reviewed by the CERN SPS Committee and by the CERN Research Board. The two boards recommended that the experiment proceeds further to a Comprehensive Design phase in the context of the new CERN Working group "Physics Beyond Colliders", aiming at presenting a CERN strategy for the European Strategy...
We report the first measurement of monoenergetic muon neutrino charged current interactions. MiniBooNE has isolated 236 MeV muon neutrino events originating from charged kaon decay at rest ($K^+→μ^+ν_μ$) at the NuMI beamline absorber. These signal $ν_μ$-carbon events are distinguished from primarily pion decay in flight $ν_μ$ and $\overline{ν}_μ$ backgrounds produced at the target station and...
In addition to its contributions to our understanding of neutrino oscillation
parameters, the T2K long-baseline neutrino oscillation experiment has a
complementary program of neutrino interaction cross-section measurements with
its near detector complex. With multiple targets (carbon, water, argon, iron),
and with on- and off-axis detectors which sample different neutrino spectra
from the same...
The T2K long-baseline neutrino oscillation experiment has been running since
January 2010 and collected thousands of neutrino-interaction events at the
near detectors (ND280 and INGRID) with different targets. The data collected
allow us not only to measure the neutrino-interaction cross sections, but
also to probe different nuclear models. T2K is developing new tools for
unfolding the data in...
Next-generation neutrino oscillation experiments, such as DUNE and Hyper-Kamiokande, hope to measure charge-parity (CP) violation in the lepton sector. In order to do this, they must dramatically reduce their current levels of uncertainty, particularly those due to neutrino-nucleus interaction models. As CP violation is a measure of the difference between the oscillation properties of...
More than 40 years after its theoretical description, the process of coherent elastic neutrino-nucleus scattering (CEvNS) has been observed for the first time by the COHERENT Collaboration, using a 14.6-kg CsI[Na] detector at the Spallation Neutron Source of Oak Ridge National Lab. COHERENT and other groups continue to work towards additional CEvNS measurements because of the breadth of...
The coherent neutrino scattering with nuclei provides a novel way to measure the distribution of neutrons in nuclei. This interaction has been theoretically predicted more than 40 years ago [1], but the difficulty of measuring the very small nuclear recoil made possible its experimental observation only in 2017 by the COHERENT experiment [2].
Using the COHERENT data, we are able to determine...
Recent advances in ways to calculate the neutrino oscillation probabilities in matter will be present as well as their utility for long baseline oscillation experiments. These methods are not only numerically accurate enough for all current and future experiments but provide better analytic understanding then other methods. How accurate an oscillation probability is needed for long baseline...
Following similar approaches in the past, the Schrodinger equation for three neutrino propagation in matter of constant density is solved analytically by two successive diagonalizations of 2x2 matrices. The final result for the oscillation probabilities is obtained directly in the conventional parametric form as in the vacuum but with explicit simple modification of two mixing angles (θ12 and...
The presence of flavoured symmetries like $U(1)_{L_e-L_\mu}$, etc. can affect the propagation of neutrinos by introducing new interactions. If the mediating gauge bosons corresponding to these symmetries are ultra light, then the nucleons and electrons in the sun can generate a long-range potential that can modify the neutrino oscillation probabilities for earth-based experiments. We study the...
There has been significant interest in the possible effect that one or more light sterile neutrinos, hinted by several short-baseline neutrino oscillation experiments, can have on the measurement of the three-neutrino mixing parameters at the future long-baseline Deep Underground Neutrino Experiment (DUNE), with a particular focus on their effect on CP-violation measurements. By the time DUNE...
Six rephasing invariant combinations can be constructed from elements of the neutrino mixing matrix $V$: $\Gamma_{ijk}=V_{1i}V_{2j}V_{3k}=R_{ijk}-iJ$, where $(i,j,k)$ is cyclic permutation of $(1,2,3)$, $R_{ijk}$ is the real part, and the common imaginary part $J$ is identified with the Jarlskog invariant. In terms of this rephasing invariant parametrization, the squared elements of the...
Abstract:
A review of theory and phenomenology of neutrino electromagnetic properties is presented. A massive neutrino even in the easiest generalization of the Standard Model inevitably has nonzero electromagnetic characteristics, at least nonzero magnetic moment. Although its value, determined by the neutrino mass, is very small, in other BSM theories much larger values of magnetic moments...
We discuss $ \mu-\tau $ reflection symmetry embedded in minimal seesaw model which predicts maximal atmospheric mixing angle and Dirac CP phase together with trivial Majorana phases for neutrinos. In this formalism, we add two right-handed neutrinos in the Standard Model which are essential to explain the tiny nature of neutrino mass under the type - I seesaw formalism. Assuming that both...
We consider a modi?cation of tribimaximal (TBM) mixing matrix which accommodates non-
zero mixing angle ?13 and CP violation. We show that such a modi?cation of TBM mixing can be
achieved in a minimal seesaw model with discrete symmetry S4. This model is very predictive and
the undetermined parameters are either mass of heavy neutrinos and a Majorana phase. Possible
values of the Dirac-type CP...
Double beta decay (DBD) is a rare nuclear process of great interest due to its potential to provide information about physics beyond the Standard Model (BSM). For example, the discovery of the neutrinoless double-beta (0νββ) decay mode could give answers to fundamental issues about possible violation of the CP and Lorentz symmetries in the weak sector, lepton number violation, or about still...
While neutrino oscillation experiments have demonstrated that neutrinos have small, nonzero masses, much remains unknown about their properties and decay modes. One potential decay mode --- neutrinoless double beta decay ($0 \nu \beta \beta$) --- is a particularly interesting target of experimental searches, since its observation would imply both the violation of lepton number conservation in...
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the...
CUPID-0 is the first large mass experiment based on cryogenic calorimeters (bolometers) that implements the dual read-out of light and heat for background rejection. The detector, consisting of 24 enriched Zn$^{82}$Se crystals (5.28 kg of $^{82}$Se), is taking data in the underground LNGS (Italy) from March 2017.
In this contribution we present the analysis that allowed to set the most...
The Advanced Mo-based Rare process Experiment (AMoRE) is a search for neutrinoless double beta decay of 100Mo in calcium molybdate (CaMoO4) crystals by using cryogenic detectors at a temperature range of tens of millikelvin. The crystals are made of Molybdenum enriched on 100Mo (≥95%) and Calcium depleted on 48Ca isotopes (≤0.002%). The ongoing pilot...
Neutrino-less double beta decay(0$\nu\beta\beta$) is acquiring great interest
after the confirmation of neutrino oscillation
which demonstrated nonzero neutrino mass.
Measurement of 0$\nu\beta\beta$ provides a test for the Majorana nature of neutrinos
and gives an absolute scale of the effective neutrino mass.
In order to search for 0$\nu\beta\beta$ of $^{48}$Ca,
we proposed CANDLES...
The reactor neutrino experiment Double Chooz observes electron-antineutrinos from two French power plants at Chooz with two identical detectors at different baselines. From the observed neutrino deficit the mixing angle theta_13 can be determined within the three flavour-scenario and signatures from further generations can be searched for. We will report the status of the experiment and...
The T2K long-baseline neutrino oscillation experiment has been running since
January 2010 and has doubled the data set in both neutrino and anti-neutrino
beam mode since results were last reported at ICHEP (2016).
We will present a joint analysis of both the neutrino and anti-neutrino
data in the disappearance and appearance channels.
This analysis uses a new event reconstruction algorithm,...
NOvA is a long-baseline neutrino experiment that uses an upgraded NuMI neutrino source at Fermilab and a 14-kton detector at Ash River, Minnesota. The detector has a highly active, finely segmented design that offers superb event identification capability. The latest results on muon (anti-)neutrino disappearance and electron (anti-)neutrino appearance will be shown, as well as neutral current...
After measuring in 2012 a relatively large value of the neutrino mixing angle θ13, the door is now open to observe for the first time a possible CP violation in the leptonic sector. The measured value of θ13 also privileges the 2nd oscillation maximum for the discovery of CP violation instead of the usually used 1st oscillation maximum. The sensitivity at this 2nd oscillation maximum is about...
Three flavor neutrino mixing has been established by the continuous studies of neutrino oscillations since its discovery. Large mixing angles and small neutrino masses, in contrast to those in quark sector, imply new physics at ultra-high energy. In addition, as- yet unmeasured CP violation in neutrino sector is considered as a clue to investigate the origin of matter-antimatter asymmetry of...
Hyper-Kamiokande (Hyper-K) succeeds the very successful Super-K experiment and will consist of a large detector filled with 260 kton water and equipped with 40% photo- coverage. Physics program of Hyper-K is broad, covering from particle physics to Astrophysics.
The 1st Hyper-K detector will be built in Japan, and the 2nd detector is considered to be built in Korea because locating the 2nd...
The neutrino masses and flavor mixings, which are missing in the Standard Model (SM), can be naturally incorporated in the type-I seesaw extension of the SM with heavy Majorana neutrinos being singlet under the SM gauge group. If the heavy Majorana neutrinos are around the electroweak scale and their mixings with the SM neutrinos are sizable, they can be produced at high energy colliders,...
CERN has launched in 2014 the design study of Future Circular Colliders, including a High Luminosity e+e- collider (FCC-ee) running from the Z pole to above the top pair production threshold. Follow a 100 TeV pp and heavy ion collider (FCC-hh) able to reach an unprecedented energy scale and an e-p collider option. The FCC-ee offers a broad discovery potential based on a combination of...
Many models of new physics beyond the Standard Model are able to describe massive, long-lived particles with macroscopic decays, which can be reconstructed inside the inner trackers of the LHC detectors. Furthermore, the lack of evidence of any new physics at the LHC motivates to perform these unconventional searches, such as looking for displaced vertices.
In left-right symmetric models,...
We will discuss all the possibilities of discovering the massive
sterile neutrinos at the LHC.
We show the 13 TeV proton-proton collider simulation in a ν-two-Higgs-doublet-model (ν-THDM). The heavy charged Higgs bosons are produced in pairs through the electroweak processes and decay to the light sterile neutrinos. The light sterile neutrino further decays into a jet-like object with a muon in it. This helps us discriminate the signal from the backgrounds with the standard model jets.
We propose a phenomenological model of the Dirac neutrino mass
matrix based on the Fridberg-Lee neutrino mass model at a special
point. In this case, the Fridberg-Lee model reduces to the
Democratic mass matrix with the $S_3$ permutation family symmetry.
The Democratic mass matrix has an experimentally unfavored
degenerate mass spectrum on the base of tribimaximal mixing
matrix. We rescue the...
Generalized neutrino-quark interactions can be studied in a fairly model-independent way by considering dimension-six effective operators constructed by only requiring Lorentz invariance. In this talk, following such approach, I will discuss the constraints on generalized neutrino-quark couplings implied by COHERENT data. I will show that some of these interactions can still be sizeable, and...
GERDA is performing a background-free search for neutrinoless double-beta decay of Ge-76. An observation of this nuclear transition would unambiguously prove that neutrinos are Majorana particles and that the lepton number is violated. Thanks to a factor two increase in statistics, the experimental sensitivity doubled compared to the last data release making GERDA the first experiment...
The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decay in $^{76}$Ge and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and $^{76}$Ge-enriched germanium detectors totalling $44.1\ \mathrm{kg}$, operating on the 4850' level of the Sanford Underground...
The search for neutrinoless double-beta decay is the most sensitive technique to establish the Majorana nature of neutrinos. Two operating experiments that look for such decays in 76Ge — GERDA and MAJORANA DEMONSTRATOR — have achieved the lowest backgrounds and the best energy resolution in the signal region. These are two of the most important detector characteristics for...
The EXO-200 experiment consists of a time projection chamber filled with ~150 kg of liquid xenon enriched at 80.7% of the 136Xe isotope. The low background level reached within the detector made possible the detection of the two neutrinos double decay of 136Xe, set the most precise measurement of a double beta decay half life to date and provided one of the most sensitive search for the...
Neutrinoless double beta decay (0$\nu\beta\beta$) is the only
practical way to understand the neutrino nature (Dirac or Majorana
particle) and to observe full lepton number violation required by most
beyond the standard model scenarios.
The goal of the SuperNEMO experiment is to search for
0$\nu\beta\beta$ decay. Its technology is based on a successful design approach of the...
Neutrinos are by far the lightest particles in the Universe. According to the Standard Model of Particle Physics neutrinos should be massless. However, the existence of their mass has been proven experimentally by the observation of neutrino mass oscillations. The KArlsruhe TRitium Neutrino (KATRIN) experiment at the Karlsruhe Institute of Technology aims for a direct neutrino mass...
The smallness of neutrino masses provides a tantalizing allusion to physics beyond the standard model. Heavy neutral leptons (HNL), such as hypothetical sterile neutrinos, accommodate a way to explain this observation, through the see-saw mechanism. If they exist, HNL could also provide answers about the dark matter nature, and baryon asymmetry of the universe. Searches for the production of...
Multiple theories beyond the Standard Model predict the existence of heavy Majorana or Dirac neutrinos. The ATLAS searches presented here focus on models in which these heavy neutral leptons are either produced together with a right-handed W gauge boson, via the Keung-Senjanovic process, or with a heavy charged lepton from the same fermionic triplet, in the context of a type-III seesaw model....
