<p>A multicomponent weakly-interacting dark matter scenario is analyzed, where the candidate dark matter states arise from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>D</mi></msub><mo stretchy="false">→</mo><msubsup><mi>Z</mi><mn>3</mn><mi>D</mi></msubsup><mo>×</mo><msubsup><mi>Z</mi><mn>2</mn><mi>acc</mi></msubsup></math> symmetry breaking triggered by a vacuum expectation value-developing scalar in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>3</mn><mo>/</mo><mn>2</mn></math> representation. While the discrete symmetries guarantee at least two stable states, a closer look at the mass orderings of the contrived dark sector reveals the existence of a third dark matter candidate, whose stability effectively results from the tight phase space in the dark boson sector. Regions of masses and couplings where the three dark states furnish a comparable contribution to the observed relic abundance are determined numerically.</p>

United States

Carlos Alvarado

Mexico

Alfredo Aranda

Chile

Cesar Bonilla

Carlos Ramos Portalatino

Multicomponent dark matter from an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>D</mi></msub><mo stretchy="false">→</mo><msubsup><mi>Z</mi><mn>3</mn><mi>D</mi></msubsup><mo>×</mo><msubsup><mi>Z</mi><mn>2</mn><mrow><mi>acc</mi></mrow></msubsup></math> scenario

We propose two models based on the <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><msub><mo>)</mo><mi>C</mi></msub><mo>×</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><msub><mo>)</mo><mi>L</mi></msub><mo>×</mo><mi>U</mi><mo>(</mo><mn>1</mn><msub><mo>)</mo><mi>X</mi></msub></math> gauge symmetry, each incorporating distinct inverse seesaw mechanisms for generating neutrino masses at the radiative level. Therefore, neutrino masses are suppressed by the radiative nature of the mass generation mechanism, which occurs after the spontaneous breaking of the global lepton number symmetry. Both scenarios discussed here are characterized by the presence of vectorlike charged leptons, which are involved in generating the masses of the Standard Model charged leptons. These additional vectorlike fermions also contribute to the anomalous magnetic moments of the muon. We perform a detailed analysis of the scalar sectors, show that these models can successfully accommodate the observed baryon asymmetry through resonant leptogenesis, and compute the rates of charged lepton flavor-violating decays, such as <math><mi>μ</mi><mo>→</mo><mi>e</mi><mi>γ</mi></math>. We discuss the constraints of the model arising from these processes and those associated with the nonunitarity of the lepton mixing matrix.

Vietnam

V. H. Binh

A. E. Cárcamo Hernández

D. T. Huong

Vishnudath K. N.

H. N. Long

P. N. Thu

Iván Schmidt

Phenomenology of 3-3-1 models with a radiative inverse seesaw mechanism

We propose a framework to account for neutrino masses at the two-loop level. This mechanism introduces new scalars and Majorana fermions to the Standard Model. It assumes the existence of a global <math><mrow><mrow><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mo>×</mo><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> symmetry which after partial breaking provides the stability of the dark matter candidates of the theory. The rich structure of the potential allows for the possibility of first-order phase transitions (FOPTs) in the early Universe which can lead to the generation of primordial gravitational waves. Taking into account relevant constraints from lepton flavor violation, neutrino physics, as well as the trilinear Higgs couplings at next-to-leading order accuracy, we have found a wide range of possible FOPTs which are strong enough to be probed at the proposed gravitational-wave interferometer experiments such as LISA.

Portugal

Sweden

João Gonçalves

Vishnudath K. N.

CERN

António P. Morais

R. Pasechnik

Gravitational waves from a scotogenic two-loop neutrino mass model

We present a Left-Right symmetric model that provides an explanation for the mass hierarchy of the charged fermions within the framework of the Standard Model. This explanation is achieved through the utilization of both tree-level and radiative seesaw mechanisms. In this model, the tiny masses of the light active neutrinos are generated via a three-loop radiative inverse seesaw mechanism, with Dirac and Majorana submatrices arising at one-loop level. To the best of our knowledge, this is the first example of the inverse seesaw mechanism being implemented with both submatrices generated at one- loop level. The model contains a global U(1) X  symmetry which, after its spontaneous breaking, allows for the stabilization of the Dark Matter (DM) candidates. We show that the electroweak precision observables, the electron and muon anomalous magnetic moments as well as the Charged Lepton Flavor Violating decays, μ → eγ, are consistent with the current experimental limits. In addition, we analyze the implications of the model for the 95 GeV diphoton excess recently reported by the CMS collaboration and demonstrate that such anomaly could be easily accommodated. Finally, we discuss qualitative aspects of DM in the considered model.

A. Cárcamo Hernández

Sergey Kovalenko

France

H. Lee

Ivan Schmidt

Fermion mass hierarchy in an extended left-right symmetric model

We propose a Majoron-like extension of the Standard Model with an extra global <math><mi>U</mi><msub><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>X</mi></mrow></msub></math>-symmetry where neutrino masses are generated through an inverse seesaw mechanism at the 1-loop level. In contrast to the tree-level inverse seesaw, our framework contains dark matter (DM) candidates stabilized by a residual <math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math>-symmetry surviving spontaneous breaking of the <math><mi>U</mi><msub><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>X</mi></mrow></msub></math>-group. We explore the case in which the DM is a Majorana fermion. Furthermore, we provide parameter space regions allowed by current experimental constraints coming from the dark matter relic abundance, (in)direct detection, and charged lepton flavor violation.

A.E. Cárcamo Hernández

Bastián Díaz Sáez

Juan Marchant González

Dark matter from a radiative inverse seesaw majoron model

The hierarchy in scale between atmospheric and solar neutrino mass splittings is investigated through two distinct neutrino mass mechanisms from tree-level and one-loop-level contributions. We demonstrate that the minimal discrete dark matter mechanism contains the ingredients for explaining this hierarchy. This scenario is characterized by adding new RH neutrinos and SU(2)-doublet scalars to the Standard Model as triplet representations of an A 4 flavor symmetry. The A 4 symmetry breaking, which occurs at the electroweak scale, leads to a residual ℤ2 symmetry responsible for the dark matter stability and dictates the neutrino phenomenology. Finally, we show that to reproduce the neutrino mixing angles correctly, it is necessary to violate CP in the scalar potential.

Germany

Johannes Herms

Spain

Omar Medina

Eduardo Peinado

Discrete dark matter mechanism as the source of neutrino mass scales

We propose a model with two Higgs doublets and several SU(2) scalar singlets with a global non-Abelian flavor symmetry   <math> <msub> <mi>Q</mi> <mn>6</mn> </msub> <mo>×</mo> <msub> <mi>Z</mi> <mn>2</mn> </msub> </math>  $$ {\mathcal{Q}}_6\times {\mathcal{Z}}_2 $$ . This discrete group accounts for the observed pattern of fermion masses and mixing angles after spontaneous symmetry breaking. In this scenario only the third generation of fermions get their masses as in the Standard Model (SM). The masses of the remaining fermions are generated through a seesaw-like mechanism. To that end, the matter content of the model is enlarged by introducing electrically charged vector-like fermions (VLFs), right handed Majorana neutrinos and several SM scalar singlets. Here we study the processes involving VLFs that are within the reach of the Large Hadron Collider (LHC). We perform collider studies for vector-like leptons (VLLs) and vector-like quarks (VLQs), focusing on double production channels for both cases, while for VLLs single production topologies are also included. Utilizing genetic algorithms for neural network optimization, we determine the statistical significance for a hypothetical discovery at future LHC runs. In particular, we show that we can not safely exclude VLLs for masses greater than 200 GeV. For VLQ’s in our model, we show that we can probe their masses up to 3.8 TeV, if we take only into account the high-luminosity phase of the LHC. Considering Run-III luminosities, we can also exclude VLQs for masses up to 3.4 TeV. We also show how the model with predicted VLL masses accommodates the muon anomalous magnetic moment.

A. Hernández

Felipe Freitas

António Morais

Collider signatures of vector-like fermions from a flavor symmetric model

We propose a Standard Model extension by a <math><mi>U</mi><mo>(</mo><mn>1</mn><msub><mo>)</mo><mi>R</mi></msub></math> gauge symmetry where only right-handed chiral fermions can carry a nontrivial charge. Here, we show that the simplest anomaly-free solution to accommodate the proton charge radius discrepancy takes right-handed muons, <math><msub><mi>μ</mi><mi>R</mi></msub></math>, and first generation quarks, <math><msub><mi>u</mi><mi>R</mi></msub></math> and <math><msub><mi>d</mi><mi>R</mi></msub></math>. Consistency with the latest muon’s (<math><mrow><mi>g</mi><mo>−</mo><mn>2</mn></mrow></math>) measurements is achieved through an extra light scalar, which itself must lie in the tens of MeV mass range to be viable.

Sub-GeV <math><mi>U</mi><mo>(</mo><mn>1</mn><msub><mo>)</mo><mi>R</mi></msub></math> gauge boson to address the proton radius discrepancy

We analyze a model with unbroken <math><mi>U</mi><msub><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow></msub></math> gauge symmetry where neutrino masses are generated at one loop, after spontaneous breaking of a global <math><mi>U</mi><msub><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow><mrow><mi>G</mi></mrow></msub></math> symmetry. These symmetries ensure dark matter (DM) stability and the Diracness of neutrinos. Within this context, we examine fermionic dark matter. Consistency between the required neutrino mass and the observed relic abundance indicates dark matter masses and couplings within the reach of direct detection experiments.

China

Brazil

Julio Leite

José W.F. Valle

Phenomenology of fermion dark matter as neutrino mass mediator with gauged B-L

Two-loop effects on the right-handed neutrino masses can have an impact on the low-energy phenomenology, especially when the right-handed neutrino mass spectrum is very hierarchical at the cutoff scale. In this case, the physical masses of the lighter right-handed neutrinos can be dominated by quantum effects induced by the heavier ones. Further, if the heaviest right-handed neutrino mass is at around the Planck scale, two-loop effects on the right-handed neutrino masses generate, through the seesaw mechanism, an active neutrino mass that is in the ballpark of the experimental values. In this paper we investigate extensions of the Planck-scale lepton number breaking scenario by additional Higgs doublets (inert or not). We find that under reasonable assumptions these models lead simultaneously to an overall neutrino mass scale and to a neutrino mass hierarchy in qualitative agreement with observations.

Alejandro Ibarra

Patrick Strobl

Neutrino parameters in the Planck-scale lepton number breaking scenario with extended scalar sectors