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Oleg Popov

Publications and source records attributed to Oleg Popov.

32 records · Page 2Linked to original sources

Radiative Dirac Neutrino Mass with Dark Matter and it's implication to $0ν4β$ in the $U(1)_{B-L}$ extension of the Standard Model

The Standard Model gauge symmetry is extended by $U(1)_{B-L}$ which when spontaneously broken leads to residual $\mathbb{Z}_4$ symmetry. $U(1)_{B-L}$ gauge symmetry made anomaly free by introducing exotic SM singlets with corresponding $U(1)_{B-L}$ charges of $13$, $-14$, and $15$. $\mathbb{Z}_4$ symmetry ensures the Dirac nature of neutrinos, simultaneously stabilizing dark matter. Dirac neutrino mass is generated through scotogenic scenario. Dark matter, direct detection, cosmological constraints, and collider constraints analysis is performed. $\mathbb{Z}_4$ symmetry predicts the exact absence of neutrinoless double beta decay ($0ν2β$) and gives a prediction for an enhanced neutrinoless quadruple beta decay ($0ν4β$) via which this model can be tested. Model allows for Majorana dark matter as well as for long-lived dark matter candidates.

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Radiative neutrino mass via fermion kinetic mixing

We propose that the radiative generation of the neutrino mass can be achieved by incorporating the kinetic mixing of fermion fields which arises radiatively at one-loop level. As a demonstrative example of the application of the mechanism, we present the particular case of the Standard Model extension by $U(1)_D$ symmetry. As a result, we show how neutrino masses can be generated via a kinetic mixing portal instead of a mass matrix with residual symmetries responsible for the stability of multicomponent dark matter.

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$SU(7)$ Unification of Scotogenic Model with Pati-Salam $SU(4)_c\otimes SU(2)_L\otimes U(1)_R$ gauge symmetry

In this work we demonstrate how Scotogenic model can arise naturally from an $SU(7)$ grand unified theory. Our model also includes a low scale Pati-Salam $SU(4)_c\times SU(2)_L\times U(1)_R$ symmetry which unifies quarks and leptons. $\mathbb{Z}_2$ symmetry needed for the realization of Scotogenic scenario is a residual symmetry and not $ad$ $hoc$. A short fermion masses and dark matter analysis is included.

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Alternative $[SU(3)]^4$ Model of Leptonic Color and Dark Matter

The alternative $[SU(3)]^4$ model of leptonic color and dark matter is discussed. It unifies at $M_U \sim 10^{14}$ GeV and has the low-energy subgroup $SU(3)_q \times SU(2)_l \times SU(2)_L \times SU(2)_R \times U(1)_X$ with $(u,h)_R$ instead of $(u,d)_R$ as doublets under $SU(2)_R$. It has the built-in global $U(1)$ dark symmetry which is generalized $B-L$. In analogy to $SU(3)_q$ quark triplets, it has $SU(2)_l$ hemion doublets which have half-integral charges and are confined by $SU(2)_l$ gauge bosons (stickons). In analogy to quarkonia, their vector bound states (hemionia) are uniquely suited for exploration at a future $e^-e^+$ collider.

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Dark Revelations of the $[SU(3)]^3$ and $[SU(3)]^4$ Gauge Extensions of the Standard Model

Two theoretically well-motivated gauge extensions of the standard model are $SU(3)_C \times SU(3)_L \times SU(3)_R$ and $SU(3)_q \times SU(3)_L \times SU(3)_l \times SU(3)_R$, where $SU(3)_q$ is the same as $SU(3)_C$ and $SU(3)_l$ is its color leptonic counterpart. Each as three variations, according to how $SU(3)_R$ is broken. It is shown here for the first time that a built-in dark $U(1)_D$ gauge symmetry exists in all six versions, and may be broken to discrete $Z_2$ dark parity. The available dark matter candidates in each case include fermions, scalars, as well as {\it vector gauge bosons}. This work points to the unity of matter with dark matter, the origin of which is not {\it ad hoc}.

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One Leptoquark to unify them? Neutrino masses and unification in the light of $(g-2)_μ$, $R_{D^{(\star)}}$ and $R_K$ anomalies

Leptoquarks have been proposed as a possible explanation of anomalies in $\bar{B}\mapsto D^{*} τ\bar{ν} $ decays, the apparent anomalies in $(g-2)_μ$ experiments and a violation of lepton universality. Motivated by this, we examine other motivations of leptoquarks: radiatively induced neutrino masses in the presence of a discrete symmetry that prevents a tree level see-saw mechanism, gauge coupling unification, and vacuum stability at least up to the unification scale. We present a new model for radiatively generating a neutrino mass which can significantly improve gauge coupling unification at one loop. We discuss this, and other models in the light of recent work on flavour anomalies.

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Dark Gauge U(1) Symmetry for an Alternative Left-Right Model

An alternative left-right model of quarks and leptons, where the $SU(2)_R$ lepton doublet $(ν,l)_R$ is replaced with $(n,l)_R$ so that $n_R$ is not the Dirac mass partner of $ν_L$, has been known since 1987. Previous versions assumed a global $U(1)_S$ symmetry to allow $n$ to be identified as a dark-matter fermion. We propose here a gauge extension by the addition of extra fermions to render the model free of gauge anomalies, and just one singlet scalar to break $U(1)_S$. This results in two layers of dark matter, one hidden behind the other.

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Quartified Leptonic Color, Bound States, and Future Electron-Positron Collider

The $[SU(3)]^4$ quartification model of Babu, Ma, and Willenbrock (BMW), proposed in 2003, predicts a confining leptonic color $SU(2)$ gauge symmetry, which becomes strong at the keV scale. It also predicts the existence of three families of half-charged leptons (hemions) below the TeV scale. These hemions are confined to form bound states which are not so easy to discover at the Large Hadron Collider (LHC). However, just as $J/ψ$ and $Υ$ appeared as sharp resonances in $e^-e^+$ colliders of the 20th century, the corresponding 'hemionium' states are expected at a future $e^-e^+$ collider of the 21st century.

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Pathways to Naturally Small Dirac Neutrino Masses

If neutrinos are truly Dirac fermions, the smallness of their masses may still be natural if certain symmetries exist beyond those of the standard model of quarks and leptons. We perform a systematic study of how this may occur at tree level and in one loop. We also propose a scotogenic version of the left-right gauge model with naturally small Dirac neutrino masses in one loop.

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Gauge $B-L$ Model of Radiative Neutrino Mass with Multipartite Dark Matter

We propose an extension of the standard model of quarks and leptons to include gauge $B-L$ symmetry with an exotic array of neutral fermion singlets for anomaly cancellation. With the addition of suitable scalars also transforming under $U(1)_{B-L}$, this becomes a model of radiative seesaw neutrino mass with possible multipartite dark matter. If leptoquark fermions are added, necessarily also transforming under $B-L$, the diphoton excess at 750 GeV, recently observed at the Large Hadron Collider, may also be explained.

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Phenomenology of the Utilitarian Supersymmetric Standard Model

We study the 2010 specific version of the 2002 proposed $U(1)_X$ extension of the supersymmetric standard model, which has no $μ$ term and conserves baryon number and lepton number separately and automatically. We consider in detail the scalar sector as well as the extra $Z_X$ gauge boson, and their interactions with the necessary extra color-triplet particles of this model, which behave as leptoquarks. We show how the diphoton excess at 750 GeV, recently observed at the LHC, may be explained within this context. We identify a new fermion dark-matter candidate and discuss its properties. An important byproduct of this study is the discovery of relaxed supersymmetric constraints on the Higgs boson's mass of 125 GeV.

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Type II Radiative Seesaw Model of Neutrino Mass with Dark Matter

We consider a model of neutrino mass with a scalar triplet $(ξ^{++},ξ^+,ξ^0)$ assigned lepton number $L=0$, so that the tree-level Yukawa coupling $ξ^0 ν_i ν_j$ is not allowed. It is generated instead through the interaction of $ξ$ and $ν$ with dark matter and the soft breaking of $L$ to $(-1)^L$. We discuss the phenomenological implications of this model, including $ξ^{++}$ decay and the prognosis of discovering the dark sector at the Large Hadron Collider.

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Neutrino Mixing and CP Phase Correlations

A special form of the $3 \times 3$ Majorana neutrino mass matrix derivable from $μ- τ$ interchange symmetry accompanied by a generalized $CP$ transformation was obtained many years ago. It predicts $θ_{23} = π/4$ as well as $δ_{CP} = \pm π/2$, with $θ_{13} \neq 0$. Whereas this is consistent with present data, we explore a deviation of this result which occurs naturally in a recent proposed model of radiative inverse seesaw neutrino mass.

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Scotogenic Inverse Seesaw Model of Neutrino Mass

A variation of the original 2006 radiative seesaw model of neutrino mass through dark matter is shown to realize the notion of inverse seesaw naturally. The dark-matter candidate here is the lightest of three real singlet scalars which may also carry flavor.

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