Higgs Decays in the Low Scale Type I See-Saw Model

A. Ibarra; C. Garcia Cely; E. Molinaro; S. T. Petcov

REVIEW

Higgs Decays in the Low Scale Type I See-Saw Model

C. Garcia Cely, A. Ibarra, E. Molinaro, S. T. Petcov

High Energy Physics - Phenomenology · Submitted 17 Aug 2012 · 31 references

Pith's verdict: The h → νN branching-ratio result is sound and new; the LHC reach curves are systematics-limited and should not be taken at face value.

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arXiv ID1208.3654 (version 2)

Pith IDEOXUQ25Y, Pith's permanent record of this paper and its review

CitationA. Ibarra, C. Garcia Cely, E. Molinaro, S. T. Petcov. "Higgs Decays in the Low Scale Type I See-Saw Model." arXiv:1208.3654 (2012). https://pith.science/paper/EOXUQ25Y

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Editor's note

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Two things worth knowing. The physics is right: the width Γ(h → ν_L N_PD) = (1/16π) y² m_h (1 − M₁²/m_h²)² follows cleanly from the Lagrangian in eq. (2), and the observation that this channel can reach BR ~ 20% while all constraints hold is genuinely new and worth having in the literature. The LHC reach in Fig. 8, though, is weaker than it looks, and the paper's word 'conservatively' for eq. (23) is backwards. On the good side: the derivation is clean, the constraint set is honestly assembled, and the bridge to MEG is a useful phenomenological connection. The paper is clear about the conditionality — the 20% figure requires saturating the MEG-derived bound on y, and the text says so even if the abstract is flatter. The collider analysis specifies cuts, smearing, and cross sections well enough to check. The soft spot is the significance calculation. At M₁ = 100 GeV, IH, 14 TeV, 10 fb⁻¹, Table 1 gives N_s = 2930 and N_b = 74000 at y = 0.04. S/√(S+B) = 10.6, but that treats the background as exactly known. A 5% background uncertainty alone adds (0.05 × 74000)² = 1.37e7 to the denominator and drops the significance to 0.8σ. At the MEG bound y ≈ 0.056 it is about 1.5σ, not below 1 as the stress test says, but still well below 3. The reach curves in Fig. 8 are systematics-limited, not statistics-limited, and the claimed complementarity — LHC probing y below the MEG bound — does not survive a realistic background treatment. The paper needs a systematics term, a control-region strategy, or a softer reach claim. This is fixable, but it should be fixed before the 3σ/5σ curves are quoted. The hand-picked relative branching benchmarks (0.55, 0.94) are less of a problem than they look: Fig. 3 shows the scan over phases that justifies them, so that's a minor point. Who should read it: anyone working on exotic Higgs decays or low-scale seesaw phenomenology. The width formula and the BR estimate are useful; the reach curves should be read with the systematics caveat in mind. Recommendation: send it to referees. The core result is sound and the systematics issue is addressable in revision.

Referee report

Significance

If the result holds, it is a useful and timely observation: the paper identifies a Higgs decay channel that is a direct probe of the neutrino Yukawa coupling in a TeV-scale see-saw, and it makes the complementarity with MEG explicit and falsifiable. The leading-order width formula is clean and internally consistent with the SM h → ff̄ formula of Eq. (12), and the numerical ratio 0.19 (y/0.05)² checks out. The collider analysis is presented with enough detail (cuts in Eqs. (19), (21), (22); smearing in Eq. (20); signal and background cross sections in Table 1) to be reproduced, which is a genuine strength. The main caveat is that the headline 20% figure is explicitly conditional on saturating the MEG-derived bound on y, and the LHC reach inherits that conditionality.

Major objections (3)

[§4, Eq. (23) and Fig. 8] The statistical significance is computed as S = Ns/√(Ns + Nb) and is described as 'conservative', but this formula treats the background as exactly known, which is not conservative when Nb/Ns is large. At M1 = 100 GeV, IH, 14 TeV, 10 fb⁻¹, Table 1 gives Ns ≈ 2930 and Nb ≈ 74000, so a 5% background uncertainty alone adds (0.05 × 74000)² ≈ 1.4 × 10⁷ to the denominator and reduces the significance from ≈ 10.6σ to below 1σ; even a 1% uncertainty leaves ≈ 3.7σ. Since the central complementarity claim is that the LHC can probe y values below the MEG bound, this systematic sensitivity is load-bearing for the reach curves in Fig. 8. The authors should either quote the reach with an explicit background-uncertainty assumption (including a data-driven sideband or shape-analysis treatment) or state the caveat prominently and soften the complementarity claim accordingly; the word 'conservative' should be removed or justified.
[Table 1] The signal cross sections are non-monotonic in M1 in a way that is not explained by the stated formulae. For NH at 8 TeV the entries are 0.061, 0.132 and 0.051 pb at M1 = 90, 100 and 110 GeV, so the 100 GeV point is about twice the 90 GeV point. However, the phase-space factor (1 − M1²/mh²)² decreases monotonically over this range (0.232, 0.130, 0.051), and the N → Wℓ branching ratio also decreases with M1 once the Z channel opens (µZ < 1 for M1 > mZ), so the product should decrease monotonically. Please explain the origin of the 90 → 100 GeV rise (e.g., acceptance, generator settings, or an error in the table), since Fig. 8's reach depends directly on these numbers.
[§4, Table 1] The background is quoted as a single number (3.45 pb at 8 TeV and 7.40 pb at 14 TeV after all cuts) with no breakdown by process, generator settings, or treatment of matching, ISR/FSR and detector simulation. This matters because the mT window 110–130 GeV in Eq. (22) lies above the W Jacobian peak at mW, where the dominant W+jets background should be strongly suppressed; a residual background of 7.4 pb after the full cut flow is large and needs justification. A process-by-process table, together with a statement of how the background was validated, would make the reach estimate credible.

Minor objections (6)

[§3, Eq. (13)] The notation conflates the branching ratio BR(h → νN) with the relative reduction of a SM channel: the chain 'BR(h → νN) ≡ Γ(h → νN)/(Γ(h → νN) + ΓSMtot) = 1 − BR(obs)/BR(SM)' is numerically correct but reads as if the branching ratio equals the reduction. It would be clearer to define the branching ratio and the relative reduction as separate quantities and then state the relation between them.
[§3, the Γ(h → νN) expression] The overall normalization 1/16π corresponds to a specific convention for the hνN coupling relative to Eq. (2); the reader cannot immediately check the factor against the Lagrangian. Please state the convention explicitly, or show the one-line derivation from Eq. (2) and Eq. (9).
[Fig. 1] The figure shows a BR(h → νN) = 0.4 contour, while the text quotes 20% as the maximum allowed value. Please state whether any part of the 0.4 contour lies outside the excluded region, and if so reconcile it with the text; if not, the 0.4 contour could be omitted or labelled as excluded everywhere.
[§4, Eqs. (19)–(22)] The mT window 110–130 GeV is optimized for mh = 125 GeV, and the signal phase space vanishes as M1 → mh. It would help to state the efficiency loss for M1 near 120 GeV and to confirm that the quoted reach curves include this effect.
[§5] The statement that the mass splitting z is 'too small to have observable effects at LHC' should be quantified, for example by giving the minimum z that would produce a resolvable mass splitting or displaced vertex in this channel.
[Fig. 8] The MEG exclusion band and the LHC reach curves appear to use different assumptions (best-fit oscillation parameters versus a scan over Dirac and Majorana phases). Please state this explicitly in the caption so that the comparison is unambiguous.

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The paper

The paper claims

The paper argues that in the low-scale type I see-saw model, the Higgs boson can decay into a light neutrino plus a heavy pseudo-Dirac neutrino with a branching ratio as large as about 20%, without violating any existing constraint fromneut

The reading

The paper asks whether the Higgs boson discovered at the LHC can decay into a light neutrino and a heavy neutrino, and whether that decay could be seen. In the low-scale type I see-saw model with two heavy Majorana neutrinos near the electroweak scale, the two heavy states pair up into a pseudo-Dirac fermion $N_{PD}$, and the same Yukawa coupling $y$ that generates the light neutrino masses also controls the Higgs coupling to $N_{PD}$. The authors show that the rate is $y^2$-suppressed but not hopelessly so: at $m_h = 125$ GeV and $M_1 = 100$ GeV the ratio to $h$ to $b$ anti-$b$ is roughly $0.19 (y/0.05)^2$, so a branching ratio near 20% survives every current bound. They then simulate the chain $h$ to $ν N_{PD}$, $N_{PD}$ to $W$ plus charged lepton, $W$ to two jets, and estimate the LHC reach. The point of interest is that a collider measurement of this exotic Higgs channel and the MEG search for $μ$ to $e γ$ probe the same coupling from opposite directions, so one can confirm or exclude the other.

What carries the argument

The load-bearing object is the pseudo-Dirac heavy neutrino $N_{PD} = (N_1 ± i N_2)/√2$, formed because the neutrino mass constraint $|Σ_k (RV)^*_{ℓ' k} M_k (RV)^†_{k ℓ}| ≲ 1$ eV forces $M_2 = M_1(1+z)$ with $z ≪ 1$ when the heavy masses sit below the Higgs mass. This near-degeneracy is what allows a large Yukawa coupling $y$ while keeping the light neutrino masses small, and it is the same coupling that appears in the Higgs vertex, in the $W$ and $Z$ couplings of $N$, and in the one-loop amplitude for $μ$ to $e γ$. The flavour structure of $(RV)_{ℓ k}$ is fixed by the oscillation data through explicit formulas for normal and inverted hierarchy, which is what makes the $e$-plus-$μ$ fraction of $N$ decays predictable: about 0.94 for inverted hierarchy and 0.20 to 0.80 for normal hierarchy.

Extended reading notes

Core claim

The central claim is that the severe constraints on the low-scale type I see-saw model, namely reproducing the measured neutrino masses and mixings, the null results on $μ$ to $e γ$, $μ$ to $3e$ and $μ$ to $e$ conversion, LEP2 searches for heavy singlet neutrinos, and electroweak precision data, still leave an open window in which the Higgs decays into a light and a heavy neutrino with a sizable branching ratio. The heavy states $N_1$ and $N_2$ must be nearly degenerate to satisfy the neutrino mass constraint, so they form a pseudo-Dirac pair, and the decay $h$ to $ν_{ℓL} N_{PD}$ has rate $Γ = (1/16π) y^2 m_h (1 - M_1^2/m_h^2)^2$. Saturating the MEG-derived limits $y ≲ 0.042$ (normal hierarchy) and $y ≲ 0.056$ (inverted hierarchy) at $M_1 = 100$ GeV gives a branching ratio up to roughly 20%, and correspondingly suppresses the Standard Model Higgs branching ratios by as much as 25%. The paper then shows that with 10 inverse femtobarns at 14 TeV, values of $y$ as small as about 0.02 with $90$ GeV $≲ M_1 ≲ 110$ GeV would give a 3 to 5 $\sigma$ signal in the one-lepton-plus-two-jets-plus-missing-energy channel.

Load-bearing premise

The sizable branching ratio requires the neutrino Yukawa coupling to sit at its current upper limit, a limit derived from the MEG bound on $μ$ to $e γ$ rather than measured, so any real coupling well below that ceiling shrinks the predicted rate quadratically.

Editorial extensions

If this is right

A Higgs decaying through $h$ to $ν N_{PD}$ suppresses every Standard Model Higgs branching ratio by up to about 25%, a deviation large enough to matter for precision Higgs coupling fits.
With 10 inverse femtobarns at 14 TeV, the LHC can probe $y ≳ 0.02$ for $90$ GeV $≲ M_1 ≲ 110$ GeV at 3 to 5 sigma, which is the same range MEG probes through $μ$ to $e γ$.
If MEG reaches $BR(μ$ to $e γ) ∼ 10^{-13}$ without a signal, the resulting bound excludes $BR(h$ to $ν N) ≳ 1%$ for $M_1 ≳ 100$ GeV, closing the collider window.
Conversely, a positive MEG signal at that level would imply Standard Model Higgs branching ratio deviations larger than 2%, up to 25%, for $70$ GeV $≲ M_1 ≲ 100$ GeV.
For $M_1 > m_h$ the exotic channels $h$ to $ν N$ to $ν ν Z$ or $ν ℓ W$ are too suppressed by $y^4$ and three-body phase space to be observable.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The whole observable window is a boundary phenomenon: the predicted rate is largest exactly where the model is about to be excluded, so a null result at both MEG and the LHC would not so much rule out the scenario as squeeze it into a corner where the heavy neutrinos decouple from everything.
Because the same $y$ sets the Higgs vertex and the $μ$ to $e γ$ loop, a joint MEG-plus-LHC null result can be read as a measurement of $y$ from above rather than merely a bound, which is a stronger statement than either experiment makes alone.
The analysis assumes the pseudo-Dirac degeneracy $z ≪ 1$; if the two heavy states were split by an amount comparable to the Higgs width, the Higgs could resolve them and the interference between the $N_1$ and $N_2$ contributions to $h$ to $ν N$ would change the rate in a way the present treatment does not track.
The same one-lepton-two-jet-plus-missing-energy signature is shared by other electroweak-scale neutrino-mass models, so the quoted reach is best read as a template for a broader class of searches rather than a test of type I see-saw alone.

Original abstract

The couplings of the low scale type I see-saw model are severely constrained by the requirement of reproducing the correct neutrino mass and mixing parameters, by the non-observation of lepton number and charged lepton flavour violating processes and by electroweak precision data. We show that all these constraints still allow for the possibility of an exotic Higgs decay channel into a light neutrino and a heavy neutrino with a sizable branching ratio. We also estimate the prospects to observe this decay at the LHC and discuss its complementarity to the indirect probes of the low scale type I see-saw model from experiments searching for the $\mu\to e\gamma$ decay.

The compiled record

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What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.32 · human participants 0.02 · controlled comparison 0.04 · randomized assignment 0.01 · states quantitative result 0.11 · compares with prior results 0.50 · mentions code or data availability 0.02.

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arXiv listing abstract v2. Results and the main claim are underlined; show every role.

The couplings of the low scale type I see-saw model are severely constrained by the requirement of reproducing the correct neutrino mass and mixing parameters, by the non-observation of lepton number and charged lepton flavour violating processes and by electroweak precision data. We show that all these constraints still allow for the possibility of an exotic Higgs decay channel into a light neutrino and a heavy neutrino with a sizable branching ratio. We also estimate the prospects to observe this decay at the LHC and discuss its complementarity to the indirect probes of the low scale type I see-saw model from experiments searching for the $\mu\to e\gamma$ decay.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	The couplings of the low scale type I see-saw model are severely constrained by the requirement of reproducing the correct neutrino mass and mixing parameters, by the non-observation of lepton number and charged lepton flavour violating processes and by electroweak precision data.	background 1.00	0.09	0.04	asserted 1.00
s1	We show that all these constraints still allow for the possibility of an exotic Higgs decay channel into a light neutrino and a heavy neutrino with a sizable branching ratio.	result 0.93	0.92	0.83	asserted 0.59
s2	We also estimate the prospects to observe this decay at the LHC and discuss its complementarity to the indirect probes of the low scale type I see-saw model from experiments searching for the $\mu\to e\gamma$ decay.	contribution 0.96	0.90	0.12	asserted 0.77

What kind of paper the classifier reports this is: theoretical result 0.99 · evidence from proof or derivation 0.48.

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sources read

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not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

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S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures

**Figure 1.** Values of the neutrino Yukawa coupling y probed by Higgs decays into NP D for mh = 125 GeV. The grey region is excluded by LEP2 data [26] and searches of lepton flavour violation [9, 25]. The cyan area represents the region of the parameter space which can be probed by the MEG experiment with the projected sensitivity to BR(µ → eγ) = 10−13 . is directly related to the neutrino Yukawa coupling y defined in eq. (9). Indeed, from the Lagrangian eq. (2) and eq. (9) we obtain: Γ(h → νN) ≡ X ℓ=e,µ,τ

**Figure 2.** Relative reduction of the Standard Model Higgs boson bra

**Figure 3.** Upper limit on the Yukawa coupling for various values of the r

**Figure 4.** Reconstructed normalized distributions 1 σ dσ d6ET vs. the missing transverse energy, 6ET , for various RH neutrino masses: M1 =120 GeV (continuous line), M1 =110 GeV (dotted line), M1 =100 GeV (short dashed line) and M1 = 90 GeV (long dashed line). where aℓ = 5% and bℓ = 0.55% for leptons, while aj = 100% and bj = 5% for jets [31]. In order to construct efficient cuts to further reduce the background we have simulated the signal for M1 = 90 GeV, 100 GeV, 110 GeV and 120 GeV using center of mass energies of 8 TeV and 14 TeV. We show the corresponding normalized differential cross…

**Figure 5.** Reconstructed normalized distributions 1 σ dσ dmjjl vs. the total invariant mass mjjl. See

**Figure 6.** Reconstructed normalized distributions 1 σ dσ dmjj vs. the invariant mass of the jets mjj . See

**Figure 7.** Reconstructed normalized distributions 1 σ dσ dmT vs. the transverse mass mT . See

**Figure 8.** Sensitivity of the LHC to the coupling y vs M1 at 3σ (continuous line) and 5σ (dashed line) and an integrated luminosity L = 1 fb−1 (thin line) and L = 10 fb−1 (thick line), for inverted hierarchy (upper panels) and normal hierarchy (lower panels) and for √ s = 8 TeV (left panels) and √ s = 14 TeV (right panels). The shaded region is excluded by the current experimental upper limit BR(µ → eγ) ≤ 2.4 × 10−12 [9]. form a pseudo-Dirac particle, NP D = (N1 + iN2)/ √ 2, with M2 = M1(1 + z), z ≪ 1. As was shown in [5], the type I see-saw scenario of interest is characterized by four real

Figures reproduced from arXiv:1208.3654 by the authors.

References

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Radiative Corrections to Light Neutrino Masses in Low Scale Type I Seesaw Scenarios and Neutrinoless Double Beta Decay
hep-ph 2015-06 conditional novelty 5.0 of 10

A heavy sterile neutrino can dominate 0vbb decay for masses above 1 GeV only at the cost of a fine-tuned cancellation, at the 10^4 to 10^9 level, between tree-level and one-loop light neutrino masses.
Probing the Type I Seesaw Mechanism with Displaced Vertices at the LHC
hep-ph 2015-05 conditional novelty 5.0 of 10

In a 3+2 Type I seesaw with degenerate few-GeV heavy neutrinos, Higgs decays can yield O(100) reconstructible displaced vertices in 300 fb^-1 at 13 TeV, but a standard muon trigger cuts the yield to a few percent.
Prospects of Heavy Neutrino Searches at Future Lepton Colliders
hep-ph 2015-03 conditional novelty 5.0 of 10

At 500 GeV with 100 inverse femtobarns, a lepton collider could probe heavy neutrino mixing down to about 10^-4 for masses up to 400 GeV, roughly ten times better than current limits.
Combining Experimental and Cosmological Constraints on Heavy Neutrinos
hep-ph 2015-02 conditional novelty 5.0 of 10

Combining direct searches, indirect precision observables and big bang nucleosynthesis leaves heavy neutrino mixings mostly bounded by direct searches alone, except for tau-flavour mixing below the D meson mass, where...
Indirect searches for sterile neutrinos at a high-luminosity Z-factory
hep-ph 2014-12 conditional novelty 5.0 of 10

Sterile neutrinos in a 3+1 toy model and a (3,3) inverse seesaw can produce BR(Z to mu tau) within FCC-ee sensitivity, while the nuMSM cannot.
Search for Heavy Right Handed Neutrinos at the FCC-ee
hep-ex 2014-11 conditional novelty 5.0 of 10

A first-look estimate finds that the proposed FCC-ee Z factory could probe heavy sterile neutrino mixings down to 10^-12 for masses of 10 to 80 GeV through displaced decays.
Imprints of massive inverse seesaw model neutrinos in lepton flavor violating Higgs boson decays
hep-ph 2014-05 conditional novelty 5.0 of 10

In the inverse seesaw model with TeV-scale right-handed neutrinos, lepton-flavor-violating Higgs decays can reach branching ratios near 10^-5 while respecting present bounds from mu to e gamma and the tau radiative decays.
Direct Bounds on Electroweak Scale Pseudo-Dirac Neutrinos from $\sqrt s=8$ TeV LHC Data
hep-ph 2014-05 conditional novelty 5.0 of 10

CMS 8 TeV multilepton data exclude light-heavy neutrino mixing above roughly 2e-3 at 100 GeV for pseudo-Dirac neutrinos, extending direct collider reach to about 500 GeV.
Probing right handed neutrinos at the LHeC and lepton colliders using fat jet signatures
hep-ph 2018-11 conditional novelty 4.0 of 10

Boosted fat-jet searches at a 1.3 to 1.8 TeV LHeC and at 1 and 3 TeV lepton colliders could probe electron-flavor heavy neutrino mixing down to about 10^-5 for neutrino masses up to roughly 2.9 TeV.
Effective Majorana mass matrix from tau and pseudoscalar meson lepton number violating decays
hep-ph 2017-12 conditional novelty 4.0 of 10

Updated constraints on sterile-neutrino mixing from lepton-number-violating meson and tau decays, with bounds on all entries of an effective Majorana mass matrix.
Extra Higgs Boson and $Z'$ as Portals to Signatures of Heavy Neutrinos at the LHC
hep-ph 2017-08 conditional novelty 4.0 of 10

A cut-and-count analysis of the 3-lepton + 2-jet + missing-energy final state shows that heavy neutrinos from a B-L model can be probed at the LHC, with modest significance at Run 2 luminosity and background-free sele...
Constraining Sterile Neutrinos from Precision Higgs Data
hep-ph 2017-04 conditional novelty 4.0 of 10

Using 8 TeV LHC Higgs data in the h to WW* to 2 lepton 2 neutrino channel, the authors bound the active-sterile neutrino mixing parameter below roughly 10^-3 to 10^-2 for sterile neutrino masses between 70 and 110 GeV.
Probing the Higgs Sector of the Minimal Left-Right Symmetric Model at Future Hadron Colliders
hep-ph 2016-02 conditional novelty 4.0 of 10

A parton-level projection finds that a 100 TeV proton collider could probe the heavy Higgs bosons of the minimal Left-Right model up to roughly 15 TeV (neutral bi-doublet) and a few TeV (triplet scalars) at 3 sigma wi...
Testing sterile neutrino extensions of the Standard Model at future lepton colliders
hep-ph 2015-02 conditional novelty 4.0 of 10

Future lepton colliders, especially FCC-ee, could probe sterile neutrino mixing parameters orders of magnitude beyond current LEP and LHC bounds, according to this forecast.
Sterile neutrinos in leptonic and semileptonic decays
hep-ph 2013-11 conditional novelty 4.0 of 10

Sterile-neutrino mixing can shift lepton-flavour-universality ratios in meson and tau decays, but current muon-to-electron-gamma bounds exclude the regions where the shifts would resolve existing tensions.
Neutrinos and Collider Physics
hep-ph 2015-02 conditional novelty 3.0 of 10

The paper reviews collider and low-energy probes of TeV-scale seesaw models, compiling current limits on heavy sterile neutrino mixing and projecting future LHC, beam-dump, and lepton-collider sensitivities.

How the literature uses it

47 arXiv papers cite this in 59 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 46 sentences without a confident label

Uses its method or tool 2 papers

In our study we also take into account current limits on invisible Higgs decays (relevant for $m_ν_s < M_H$), following the approach derived in [ref] .

Effective Majorana mass matrix from tau and pseudoscalar meson lepton number violating decays · Constraints on sterile fermions · 0.95
In our study we also take into account current limits on invisible Higgs decays (relevant for $m_ν_s < M_H$), following the approach derived in [ref] .

In-flight cLFV conversion: $e-\mu$, $e-\tau$ and $\mu-\tau$ in minimal extensions of the Standard Model with sterile fermions · Constraints on sterile fermions · 0.90

Uses its data or values 1 paper

LHC data on invisible Higgs decays already allows to constrain regimes where the sterile states are below the Higgs mass; in our study we apply the constraints derived in [ref] .

Impact of sterile neutrinos on nuclear-assisted cLFV processes · Constraints on sterile fermions · 0.81

Compares with it 2 papers

[ref] and [ref] , where the event signature has been analysed more carefully.

Testing sterile neutrino extensions of the Standard Model at future lepton colliders · Higgs boson decays at the LHC · 0.94
The phenomenology of the Higgs decays $h→ν_ℓL N_k$ in the model considered in the present article is similar to that of the same decay investigated in detail in [ref] in the model discussed in [ref] .

Low-Scale Seesaw and the CP Violation in Neutrino Oscillations · LFV Observables and Higgs Decays · 0.86

Cites it as background 8 papers

Attempts to probe it have been carried out for both prompt [ref] and long-lived heavy neutrinos [ref] .

Bounding the Dimension-5 Seesaw Portal with Non-Pointing Photon Searches · Introduction · 0.91
Detailed analyses of the parameter space and of various constraints can be found e.g. in Refs. [ref] .

Fermionic extensions of the Standard Model in light of the Higgs couplings · Majorana leptons · 0.90
For discussions on this topic, see, for example, Refs. [ref] .

Natural quark mixing and inverse seesaw in a left-right model with an axion · Lepton flavour violation and heavy neutrino constraints · 0.89

What it cites · 25 sentences without a confident label

Uses the method or tool of 1 paper

We have simulated with Madgraph [ref] the process of production of a Higgs boson at the LHC, which decays $h→νN$.

MadGraph 5 : Going Beyond · Searches for the New Channel $h→νN$ at LHC · 1.00

Uses data or values from 5 papers

We also show the excluded region (grey area) by the results of i) the search for the $μ→eγ$ decay with the MEG experiment [ref] , ii) the search for $μ-e$ conversion in Ti [ref] and iii) the search for heavy singlet neutrinos in $Z$ boson decays at LEP2 [ref] .

New limit on the lepton-flavour violating decay mu -> e gamma · New Higgs Decay Channels · 0.80
Taking the best fit values of the neutrino oscillation parameters [ref] , we get the upper limits: [equation] These upper limits are roughly of the same order as the bottom Yukawa coupling, $y_b=m_b/v≃0.024$.

Global status of neutrino oscillation parameters after Neutrino-2012 · Preliminary Remarks · 0.99
where $a_ℓ= 5%$ and $b_ℓ= 0.55%$ for leptons, while $a_j = 100%$ and $b_j = 5%$ for jets [ref] .

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics · Searches for the New Channel $h→νN$ at LHC · 0.99

Cites as background 7 papers

In the following we consider the TeV scale type I see-saw scenarios with two RH neutrinos discussed in [ref] .[Type I see-saw scenarios with two heavy Majorana neutrinos having masses by few to several orders of magnitude below the GUT scale of $∼2×10^16$ GeV have been discussed, e.g., in [ref] .]

The See-Saw Mechanism, Neutrino Yukawa Couplings, LFV Decays l_i to l_j + gamma and Leptogenesis · Preliminary Remarks · 0.81
In the following we consider the TeV scale type I see-saw scenarios with two RH neutrinos discussed in [ref] .[Type I see-saw scenarios with two heavy Majorana neutrinos having masses by few to several orders of magnitude below the GUT scale of $∼2×10^16$ GeV have been discussed, e.g., in [ref] .]

TeV Scale See-Saw Mechanisms of Neutrino Mass Generation, the Majorana Nature of the Heavy Singlet Neutrinos and $\betabeta$-Decay · Preliminary Remarks · 0.81
In the following we consider the TeV scale type I see-saw scenarios with two RH neutrinos discussed in [ref] .[Type I see-saw scenarios with two heavy Majorana neutrinos having masses by few to several orders of magnitude below the GUT scale of $∼2×10^16$ GeV have been discussed, e.g., in [ref] .]

Low Energy Signatures of the TeV Scale See-Saw Mechanism · Preliminary Remarks · 0.81

Discussion

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