An extension of the Standard Model with anomaly free $U(1)_F$ flavor symmetry is studied in this paper. With this extension and the addition of the right-handed neutrino states, the solution of anomaly free charge assignments is found, which gives appealing texture zero and hierarchical Yukawa matrices. This gives us a natural understanding of the hierarchies between charged fermion masses and Cabibbo-Kobayashi-Maskawa (CKM) matrix elements. Neutrino Dirac and Majorana coupling matrices also have desirable structures leading to successful neutrino oscillations with inverted neutrino mass ordering. Other interesting implications of the presented scenario are also discussed.
We study a neutrino model introducing an additional nontrivial gauged lepton symmetry where the neutrino masses are induced at two-loop level while the first and second charged-leptons of the standard model are done at one-loop level. As a result of model structure, we can predict one massless active neutrino, and there is a dark matter candidate. Then we discuss neutrino mass matrix, muon anomalous magnetic moment, lepton flavor violations, oblique parameters, and relic density of dark matter taking into account the experimental constraints.
Massive neutrino is an evidence of new physics beyond the Standard Model. One of the well motivated new physics scenarios is a model with gauged lepton flavor symmetry. We investigate neutrino properties in the minimal SU$(3)_\ell\times$SU$(3)_E$ gauged lepton flavor model. In this model, three new species of fermions are introduced to cancel gauge anomalies. These new fermions lead to a see-saw mechanism for neutrino mass generation. We impose the constraints from perturbative unitarity in 2-2 scattering processes, as well as current experimental constraints, to obtain viable neutrino spectru…
We propose a new model with flavor-dependent gauged $U(1)_{B-L_1}\times U(1)_{B-L_{2}-L_{3}}$ symmetry in addition to the flavor-blind one in the standard model. The model contains three right-handed neutrinos to cancel gauge anomalies and several Higgses to construct the measured fermion masses. We show the generic feature of the model and explore its phenomenology. In particular, we discuss the current bounds on the extra gauge bosons from the K and B meson mixings as well as the LEP and LHC data and focus on their contributions to the lepton flavor violating processes of $\ell_{i+1}\to \ell…
We propose a model with flavor dependent gauged symmetries of $\displaystyle \prod_{i=1}^3 U(1)_{B_i-L_i}$ with $i$ the family indices. After formulating the renormalizable Yukawa Lagrangian, Higgs potential and kinetic term, we study the lepton sector based on a successful two-zero texture without introducing extra scalar bosons to avoid the dangerous Goldstone bosons. In particular, we discuss the muon related phenomenologies via additional neutral gauge bosons. In our numerical analysis, we explore the allowed parameter space, in which the anomaly of $B \to K^* \bar μμ$ can be explained.
Beyond Standard Model physics frequently connects flavor symmetry with a discrete group. If the discrete symmetry arises spontaneously from a gauge theory, one can maintain compatibility with quantum gravity and avoid anomalies. We provide an example of such a model with the Standard Model gauge group extended to $SU(3)_C \times SU(2)_L \times U(1)_Y \times SU(2)_{T'} $ where the binary tetrahedral flavor group $T'$ is embedded in $SU(2)_{T'}$. Quark and lepton masses and mixing angles are fit to data, where lepton mixing angles are shifted from tribimaximal values by the addition of scalar VE…
In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario that scotogenic neutrino and flavored mediator share the same inert Higgs doublet and all are charged under a hidden gauged $U(1)$ symmetry. The dark Z2 symmetry in dark sector is regarded as the remnant of this hidden $U(1)$ symmetry breaking. In particular, we investigate a dark $U(1)_D$ (and also a $U(1)_{B-L}$) model which unifies scotogenic neutrino and top-flavored mediator. In this model dark tops and dark n…
We present an economical model where an $S^{}_1$ leptoquark and an anomaly-free $U(1)^{}_X$ gauge symmetry with $X = B^{}_3-2L^{}_μ/3-L^{}_τ/3$ are introduced, to account for the muon anomalous magnetic moment $a^{}_μ\equiv (g^{}_μ-2)$ and flavor puzzles including $R^{}_{K^{(\ast)_{}}}$ and $R^{}_{D^{(\ast)_{}}}$ anomalies together with quark and lepton flavor mixing. The $Z^\prime_{}$ gauge boson associated with the $U(1)^{}_X$ symmetry is responsible for the $R^{}_{K^{(\ast)_{}}}$ anomaly. Meanwhile, the specific flavor mixing patterns of quarks and leptons can be generated after the spontan…
We propose a model having a gauged $SU(2)$ symmetry associated with the second and third generations of leptons, dubbed $SU(2)_{μτ}$, of which $U(1)_{L_μ-L_τ}$ is an Abelian subgroup. In addition to the Standard Model fields, we introduce two types of scalar fields. One exotic scalar field is an $SU(2)_{μτ}$ doublet and SM singlet that develops a nonzero vacuum expectation value at presumably multi-TeV scale to completely break the $SU(2)_{μτ}$ symmetry, rendering three massive gauge bosons. At the same time, the other exotic scalar field, carrying electroweak as well as $SU(2)_{μτ}$ charges, …
We study the seesaw mechanism in the supersymmetric standard model (SSM) with ${\mathbb Z}_3$ symmetry instead of the R-parity, so-called {\it Matter triality} ($M_3$). This Abelian discrete symmetry prohibits the baryon/lepton number violation operators at the non-renormalizable level, and the proton longevity is ensured. The lepton number violation term by the right-handed neutrino is only allowed under the symmetry, it plays a role of the Majorana mass after the right-handed sneutrino develops into the vacuum expectation value. The mass of the active neutrino is generated from the two contr…
We consider a singlet fermionic dark matter (DM) $χ$ in a gauged $U(1)_{B-3L_i}$ extension of the Standard Model (SM), with $i\in e\,,μ\,,τ$, and derive bounds on the allowed parameter space, considering its production via freeze-in mechanism. The DM communicates with the SM only through flavorful vector-portal $Z_\text{B3L}$ due to its non-trivial charge $x$ under $U(1)_{B-3L_{i}}$, which also guarantees the stability of the DM over the age of the Universe for $x\neq\{\pm 3/2,\pm 3\}$. Considering $Z_\text{B3L}$ to lie within the mass range of a few MeV up to a few GeV, we obtain constraints …
A new heavy $Z'$ vector boson provides a possible explanation for the neutral current B anomalies and points to the scale where we expect the solution to the hierarchy problem to appear. In this paper, we explore a modified Top Seesaw model based on the global symmetry breaking of $U(3)_L$ to $U(2)_L$. The symmetry is partially gauged such that the breaking introduces not only a composite Higgs doublet but also a TeV-scale $Z'$ boson. The $U(3)_L/U(2)_L$ Top Seesaw model predicts a light Higgs boson as well as a large top Yukawa coupling. Additional $U(1)'$ symmetry is gauged such that a flavo…
The $3.1σ$ $R_K$ anomaly after Moriond 2021 and $3.3 σ$ $Δa_μ$ from Fermilab Muon g-2 experiment implicate that the lepton flavor universality violation (LFUV) may play a role in the exploration of new physics. A Flavor Gauged Two-Higgs Doublet Model (FG2HDM) is proposed and investigated in this work. To get rid of the the redundancy in Yukawa coupling of 2HDM-III, a specific U(1) flavor symmetry is introduced. The charge difference between two scalar doublet forbid the appearance of pseudoscalar and hence there are only three particles (a charged and neutral heavy scalar together with a neutr…
To explain quark and lepton masses and mixing angles, one has to extend the standard model, and the usual practice is to put the quarks and leptons into irreducible representations of discrete groups. We argue that discrete flavor symmetries (and their concomitant problems) can be avoided if we extend the gauge group. In the framework of SU(12) we give explicit examples of models having varying degrees of predictability obtained by scanning over groups and representations and identifying cases with operators contributing to mass and mixing matrices that need little fine- tuning of prefactors. …
We consider an explanation of CDF II W bosom mass anomaly by $Z-Z'$ mixing with $U(1)_R$ gauge symmetry under which right-handed fermions are charged. It is found that $U(1)_R$ is preferred to be leptophobic to accommodate the anomaly while avoiding other experimental constraints. In such a case we require extra charged leptons to cancel quantum anomalies and the SM charged leptons get masses via interactions with the extra ones. These interactions also induce muon $g-2$ and lepton flavor violations. We discuss muon $g-2$, possible flavor constraints, neutrino mass generation via inverse seesa…
我们构造了一个无异常扩展的左右对称模型，其中的最大味群是规范的，并通过添加新的类矢量费米子态来保证异常消除。我们解决的问题，最低允许的味道对称尺度与数据一致。由于Grinstein等人最近指出的机制，树水平的味道改变中性电流原来起着非常弱的约束作用。在我们的模型中，对于电弱精密观测量也是如此。主要的约束原来来自WR介导的风味改变中性电流盒图，主要是K-Kbar混合。在离散宇称对称的情况下，目前在TeV尺度，这一约束意味着较低的边界上的矢量费米子和味玻色子的质量分别为5和10 TeV。然而，当在TeV尺度上只恢复SU（2）_R x U（1）_{B-L}而不恢复宇称时，这些限制被削弱了。例如，假设SU（2）规范耦合的gR/gL比约为0.7，则上述限制对于矢量费米子和味玻色子都可以降低一半。我们的模型提供了一个框架，容纳中微子的质量，在宇称对称的情况下，提供了一个解决方案的强CP问题。由于大爆炸核合成的限制，轻子味标度上的束缚更强一些。然而，我们认为，这些限制的适用性取决于在工作中产生中微子质量的机制。
We study a model with $U(1)$ gauged lepton number symmetry in which the active neutrino masses are generated at two-loop level through the spontaneous breaking of the lepton number symmetry. To cancel gauge anomalies some exotic leptons are introduced that also play an important role in generating neutrino masses and the lightest neutral one can be a dark matter candidate. We discuss a phenomenology of the neutral fermion sector including dark matter, lepton flavor violations, and an extra neutral gauge boson $Z'$ that can be tested by $e^+ e^-$ collision at the International Linear Collider (…
We propose a hidden gauged $U(1)_H$ $Z'$ model to explain deviations from the Standard Model (SM) values in lepton flavor universality known as $R_K$ and $R_D$ anomalies. The $Z'$ only interacts with the SM fermions via their mixing with vector-like doublet fermions after the $U(1)_H$ symmetry breaking, which leads to $b \to s μμ$ transition through the $Z^{\prime}$ at tree level. Moreover, introducing an additional mediator, inert-Higgs doublet, yields $b\to c τν$ process via charged scalar contribution at tree level. Using flavio package, we scrutinize adequate sizes of the relevant Wilson c…
Despite the popularity of two-Higgs-doublet models (2HDMs) with a gauged abelian flavor symmetry, the allowed Yukawa textures have only been partly explored so far. In this work, we classify and compare every anomaly-free instance, in the case of having two generations of right-handed neutrinos and a type-I seesaw mechanism. We found 16 valid implementations in total, out of which 11 agree well with current experimental bounds. To our knowledge, neither of these models have been considered previously.
We propose a predictively radiative neutrino mass model with gauged $U(1)_{B-2L_{\ell_2}-L_{\ell_1}}$ symmetry in which we successfully realize two-zero textures of neutrino mass matrix depending on charge assignment for leptons and the singlet scalar fields. Then some correlations of neutrino parameters are shown where we take mass structure given by $(\ell_2, \ell_1) = (μ, τ)$ or $(μ, e)$ as a representative case. Furthermore we discuss phenomenology of the model such as lepton flavor violations, collider physics, and dark matter candidate.
We discuss a classically conformal radiative neutrino model with gauged B$-$L symmetry, in which the B$-$L symmetry breaking can occur through the Coleman-Weinberg mechanism. As a result, Majorana mass term is generated and EW symmetry breaking also occurs. We show some allowed parameters to satisfy several theoretical and experimental constraints. Theoretical constraints are inert conditions and Coleman-Weinberg condition. Experimental bounds are lepton flavor violation(especially μ-> e γ), the current bound on the $Z'$ mass at LHC, in additions to the neutrino oscillations.
The basic features of quark and lepton mass matrices can be successfully explained by natural minima of a generic potential with dynamical Yukawa fields invariant under the $[\mathrm{SU(3)}]^5\times \mathcal{O}(3)$ flavor symmetry. If this symmetry is gauged, in order to avoid potentially dangerous Goldstone bosons, and small perturbations are added to exactly fit the observed pattern of fermion masses, the spectrum of massive flavor gauge bosons can naturally explain the hints for new physics in $b\to s \ell^+\ell^-$ transitions, including $R_K$. In particular, the desired pattern of the Stan…
We study neutrino and dark matter based on a gauged $U(1)_R$ symmetry in a framework of radiative seesaw scenario. Identifying dark matter as a bosoninc particle, it interacts with quark and lepton sectors through vector-like heavier quark and leptons, and plays an role in generating neutrino mass matrix together with neutral heavier fermions. We explore several constraints for masses and couplings related to dark matter by computing relic density and direct search, taking the neutrino oscillation, lepton flavor violations, and muon anomalous magnetic moment into account. Finally, we briefly m…
We construct a novel flavor-dependent gauged lepton number $U(1)_\ell$ model for the hierarchical charged lepton masses and the observed $(g-2)_{e,μ}$. Only tau participates in the tree-level Standard Model ( SM ) Yukawa interaction. At the same time, the masses of electron and muon are light due to radiative generation and(or) the heavy-mediator-suppressed Yukawa coupling to the SM Higgs. Not only can the measured anomalous magnetic dipole moment of the muon, $\triangle a_μ$, be explained, but the positive (or negative) $\triangle a_e$ can also be accommodated in this model. Without additiona…
We propose a simple extension of the standard model where neutrinos get naturally small "scotogenic" Dirac masses from an unbroken gauged $B-L$ symmetry, ensuring dark matter stability. The associated gauge boson gets mass through the Stueckelberg mechanism. Two scenarios are identified, and the resulting phenomenology briefly sketched.
Two-Higgs-doublet models (2HDMs) with a flavored U(1)' gauge symmetry are a popular extension to the Standard Model (SM), yet they currently lack a complete survey. In this paper, we present a full classification of anomaly-free 2HDMs within the SM fermion content, resulting in a total of eleven distinct models. Four of these are relatively well-studied, while the rest either partially, or entirely, lack previous treatment. We study these textures under a variety of experimental bounds, focusing mainly on the previously unexplored models. This work is intended to act as a catalog to models wor…
We consider gauged U(1) extensions of the standard model of particle physics with three right-handed sterile neutrinos and a singlet scalar. The neutrinos obtain mass via the type I seesaw mechanism. We compute the one loop corrections to the elements of the tree level mass matrix of the light neutrinos and show explicitly the cancellation of the gauge dependent terms. We present a general formula for the gauge independent, finite one-loop corrections for arbitrary number new U(1) groups, new complex scalars and sterile neutrinos. We estimate the size of the corrections relative to the tree le…
Universidad Técnica Federico Santa María（费德里科·圣玛丽亚技术大学）；Centro Científico-Tecnológico de Valparaíso（瓦尔帕莱索科技中心）；Millennium Institute for Subatomic Physics at High-Energy Frontier (SAPHIR)（高能前沿子物理千年研究所（SAPHIR））；Universidad de Guanajuato（瓜纳华托大学）；Universidad Andres Bello（安德烈斯·贝略大学）；Universidad Nacional Autónoma de México（墨西哥国立自治大学）；Secretaría de Ciencia, de Humanidades, Tecnología e Innovación（科学、人文、技术与创新秘书处）
The "gauged'' Peccei-Quinn (PQ) mechanism of Fukuda, Ibe, Suzuki and Yanagida is implemented in the flavorful axion model of Carone and Merchand. This model of flavor is similar to other successful ones based on the double tetrahedral group, but the flavor symmetry includes a global U(1) factor that leads to the presence of a flavorful axion. Here we gauge that U(1) symmetry and introduce a heavy sector that includes (1) the fermions necessary to cancel anomalies and (2) a second scalar flavon field that spontaneously breaks the U(1) symmetry. The full theory has an accidental U(1)$\times$U(1)…
We propose a model which generates neutrino masses by the inverse seesaw mechanism, provides a viable dark matter candidate and explains the muon ($g-2$) anomaly. The Standard Model (SM) gauge group is extended with a gauged U(1)$_{\rm B-L}$ as well as a gauged U(1)$_{\rm L_μ - L_τ}$. While U(1)$_{\rm L_μ - L_τ}$ is anomaly free, the anomaly introduced by U(1)$_{\rm B-L}$ is cancelled between the six SM singlet fermions introduced for the inverse seesaw mechanism and four additional chiral fermions introduced in this model. After spontaneous symmetry breaking the four chiral fermionic degrees …
We discuss a linear seesaw model with as minimum field content as possible, introducing a modular $S_4$ with the help of gauged $U(1)_{B-L}$ symmetries. Due to rank two neutrino mass matrix, we have a vanishing neutrino mass eigenvalue, and only the normal mass hierarchy of neutrinos is favored through the modular $S_4$ symmetry. In our numerical $Δχ^2$ analysis, we especially find rather sharp prediction on sum of neutrino masses to be around $60$ meV in addition to the other predictions.
