<p>We propose a simple and predictive setup that connects neutrino masses, dark matter (DM), and gravitational waves. A minimal lepton parity DM scenario is considered where the residual symmetry <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mo>−</mo><mn>1</mn><msup><mo stretchy="false">)</mo><mi>L</mi></msup></math> from the type I seesaw acts as the dark parity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo>=</mo><mo stretchy="false">(</mo><mo>−</mo><mn>1</mn><msup><mo stretchy="false">)</mo><mrow><mi>L</mi><mo>+</mo><mn>2</mn><mi>j</mi></mrow></msup></math>, ensuring DM stability without imposing any new symmetry. A singlet Majorana fermion <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> with even lepton parity serves as the DM candidate, interacting via a real scalar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi></math> which is also even lepton parity. The scalar potential possesses an accidental <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">Z</mi><mn>2</mn></msub></math> symmetry, whose spontaneous breaking gives rise to unstable domain walls in the presence of explicit <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">Z</mi><mn>2</mn></msub></math>-breaking terms allowed by the lepton parity. The subsequent domain wall annihilation generates a stochastic gravitational wave background potentially observable at different gravitational wave experiments.</p>

United States

Ernest Ma

India

Partha Kumar Paul

Narendra Sahu

Lepton parity dark matter and naturally unstable domain walls

Implementing the Peccei-Quinn mechanism to enforce <italic>CP</italic> conservation in strong interactions with heavy dark quarks, a scotogenic model of quark masses with <math altimg='si1.svg'><msub><mrow><mi>Z</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>&#215;</mo><msub><mrow><mi>Z</mi></mrow><mrow><mn>3</mn></mrow></msub></math> symmetry is discussed where there is only one Higgs doublet. A natural extension to the lepton sector using <math altimg='si2.svg'><msub><mrow><mi>A</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>&#215;</mo><msub><mrow><mi>A</mi></mrow><mrow><mn>4</mn></mrow></msub></math> is also presented.

Scotogenic peccei-quinn and one-Higgs quark and lepton model with flavor symmetry

Preserving the unique role of the one Higgs doublet of the standard model, it is proposed that quark and lepton mass patterns, often ascribed to the Froggatt-Nielsen mechanism using nonrenormalizable higher-dimensional terms, may be enforced in a <underline>renormalizable</underline> theory of just one Higgs doublet by the scotogenic mechanism with soft symmetry breaking in the dark sector. A revised version of the original <math altimg='si1.svg'><msub><mrow><mi>A</mi></mrow><mrow><mn>4</mn></mrow></msub></math> model of charged leptons and neutrinos is discussed.

Scotogenic Froggatt-Nielsen and the versatility of soft symmetry breaking

It is pointed out that every renomalizable field theory has a symmetry which is hidden in plain sight. In all practical cases, it is also broken softly, either explicitly or spontaneously. The soft explicit breaking mass terms may be assumed naturally small compared to the scalar mass-squared terms. Implications for extensions of the standard model are discussed. New left-right model of two-loop radiative Dirac neutrino mass is proposed.

Softly broken hidden symmetry in every renormalizable field theory

Dark matter is postulated as a light fermion in two natural scenarios as the outcome of a softly broken discrete symmetry. It is produced from the naturally suppressed decay of the standard-model Higgs boson through the freeze-in mechanism.

Light dark fermion in two natural scenarios

The addition of a Higgs quadruplet to the standard model (SM) of quarks and leptons would shift the <math><mi>W</mi></math>-boson mass upward. It could also facilitate the production of dark matter through the conventional thermal freeze-out scenario via Yukawa interaction with the Higgs quadruplet or freeze-in production from the decay of SM Higgs. We investigate the same-sign lepton smoking gun signature of the double-charged scalar component of the quadruplet Higgs at the LHC.

Bangladesh

Talal Ahmed Chowdhury

Egypt

Kareem Ezzat

Shaaban Khalil

South Korea

Dibyendu Nanda

Higgs quadruplet impact on <math><mi>W</mi></math> mass shift, dark matter, and LHC signatures

If dark matter is light, it may be due to a seesaw mechanism just as neutrinos are. It is postulated that both originate from the same type of heavy fermion anchors, either singlets or triplets. In the latter case, a shift of the W mass is predicted, as suggested by the CDF precision measurement. A spontaneously broken dark <math><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></math> gauge symmetry is assumed, resulting in freeze-in long-lived light dark matter.

Parallel seesaw mechanisms for neutrinos and freeze-in long-lived dark matter

Radiative Dirac neutrino masses and their mixing are linked to dark matter through the non-Abelian discrete symmetry <math><msub><mrow><mi>A</mi></mrow><mrow><mn>5</mn></mrow></msub></math> of the 4-dimensional pentatope, softly broken to <math><msub><mrow><mi>A</mi></mrow><mrow><mn>4</mn></mrow></msub></math> of the 3-dimensional tetrahedron. This unifying understanding of neutrino family structure from dark matter is made possible through the interplay of gauge symmetry, renormalizable Lagrangian field theory, and softly broken discrete symmetries. Dark neutral fermions are produced through Higgs decay.

Scotogenic → Dirac neutrinos with freeze-in dark matter

The dark sector is postulated to be invariant under an <math><mi>S</mi><mi>U</mi><mo>(</mo><mn>2</mn><mo>)</mo></math> gauge symmetry, spontaneously broken by a Higgs quadruplet to a conserved residual <math><msub><mrow><mi>Z</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>×</mo><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math> symmetry. The resulting dark matter phenomenology is studied.

Debasish Borah

Dark (2)→ × Gauge Symmetry

Dark matter is postulated to transform under the non-Abelian <math><mi>S</mi><mi>U</mi><msub><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow><mrow><mi>D</mi></mrow></msub></math> gauge symmetry. Its connection to Dirac neutrino masses is explored.