We study and analyze the electric dipole moments (EDMs) of neutron and heavy quarks c, t in a CP-violating (CPV) supersymmetric U(1) extension of the standard model called $U(1)_X$SSM, whose local gauge group is $U(1)_X\times SU(3)_C\times SU(2)_L \times U(1)_Y$. The contributions from the one loop diagrams and the Weinberg operators are taken into account with the new introduced CPV phases beyond the minimum supersymmetric standard model(MSSM) being non-zero. Our numerical results show that in $U(1)_X$SSM the neutron EDM can be smaller than its experimental upper bound $1.8\times10^{-26}$ e$\cdot$cm without a small CPV phase. The magnitudes of EDMs of heavy quarks c and t can reach $10^{-24}$ e$\cdot$cm. and $10^{-22}$ e$\cdot$cm respectively. This is favorable to the study of CPV.
$U(1)_X$SSM is the extension of the minimal supersymmetric standard model(MSSM) and its local gauge group is $SU(3)_C\times SU(2)_L \times U(1)_Y \times U(1)_X$. To obtain this model, three singlet new Higgs superfields and right-handed neutrinos are added to MSSM. In the framework of $U(1)_X$SSM, we study lepton flavor violating decays $τ\rightarrow{Pl}(P=π,~η,~η^\prime;~l=μ,~e)$. According to the latest experimental data of $τ\rightarrow{Pe}$ and $τ\rightarrow{Pμ}$, the influence of different sensitive parameters on the results is analyzed to make a reasonable prediction for future experimen…
Three singlet new Higgs superfields and right-handed neutrinos are added to MSSM to obtain $U(1)_X$SSM model. Its local gauge group is $SU(3)_C\times SU(2)_L \times U(1)_Y \times U(1)_X$. In the framework of $U(1)_X$SSM, we study muon anomalous magnetic moment and lepton flavor violating decays $l_j\rightarrow{l_iγ}(j=2,3;i=1,2)$ within the Mass Insertion Approximation(MIA). Through the MIA method, we can find the parameters that directly affect the analytical result of the lepton flavor violating decays $l_j\rightarrow{l_iγ}$, which make our work more convenient. We want to provide a set of s…
The minimal supersymmetric extension of the standard model (MSSM) is extended to the $U(1)_X$SSM, whose local gauge group is $SU(3)_C \times SU(2)_L \times U(1)_Y \times U(1)_X$. To obtain the $U(1)_X$SSM, we add the new superfields to the MSSM, namely: three Higgs singlets $\hatη,~\hat{\barη},~\hat{S}$ and right-handed neutrinos $\hatν_i$. The CP violating effects are considered to study the lepton electric dipole moment(EDM) in $U(1)_X$SSM. The CP violating phases in $U(1)_X$SSM are more than those in the standard model(SM). In this model, some new parameters $(θ_S, θ_{BB^{\prime}}, θ_{BL})$…
To solve the $μ$ problem and generate three tiny neutrino masses in the MSSM, the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM) introduces three singlet right-handed neutrino superfields, which lead to the mixing of the Higgs doublets with the sneutrinos. The mixing affects the lightest Higgs boson mass and the Higgs couplings. The present observed 95\% CL upper limit on signal strength of the 125 GeV Higgs boson decay $h\rightarrow Zγ$ is 6.6, which still is plenty of space to prove the existence of new physics. In this work, we investigate the signal strength of the 125 GeV Higgs boso…
$μν$SSM is an $R$-parity violating non-minimal supersymmetric model which uses right chiral neutrino superfields to solve the $μ$-problem. The $R$-parity violation together with a TeV scale seesaw mechanism using right handed neutrinos are instrumental for the light neutrino mass generation in $μν$SSM. We show that it is possible to accommodate three flavour global neutrino data in $μν$SSM with three massive neutrinos at the tree level. Ingression of the one-loop corrections to neutrino masses and mixing shows certain variations over the tree level analysis depending on the specific hierarchy …
Within framework of the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM), exotic singlet right-handed neutrino superfields induce new sources for lepton-flavor violation. In this work, we investigate some lepton-flavor violating processes in detail in the $μν$SSM. The numerical results indicate that the branching ratios for lepton-flavor violating processes $μ\rightarrow eγ$, $τ\rightarrowμγ$ and $μ\rightarrow3e$ can reach $10^{-12}$ when $\tanβ$ is large enough, which can be detected in near future. We also discuss the constraint on the relevant parameter space of the model from the muon …
In the supersymmetric standard model (SSM) the $W$-boson could have a non-vanishing electric dipole moment (EDM) through a one-loop diagram mediated by the charginos and neutralinos. Then the $W$-boson EDM induces the EDMs of the neutron and the electron. We discuss these EDMs, taking into consideration the constraints from the neutron and electron EDMs at one-loop level induced by the charginos and squarks or sleptons. It is shown that the neutron and the electron could respectively have EDMs of order of $10^{-26}e$cm and $10^{-27}e$cm, solely owing to the $W$-boson EDM. Since these EDMs do n…
The electric dipole moments (EDMs) of the neutron and the electron are reviewed within the framework of the supersymmetric standard model (SSM) based on grand unified theories coupled to N=1 supergravity. Taking into account one-loop and two-loop contributions to the EDMs, we explore SSM parameter space consistent with experiments and discuss predicted values for the EDMs. Implications of baryon asymmetry of our universe for the EDMs are also discussed.
Recently, the Muon g-2 experiment at Fermilab has measured the muon anomalous magnetic dipole moment (MDM), $a_μ=(g_μ-2)/2$, which reported that the new experimental average increases the tension between experiment and the standard model (SM) prediction to 4.2$σ$. In this work, we reanalyse the muon anomalous MDM at two-loop level in the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM) combined with the updated experimental average. The $μν$SSM can explain the current tension between the experimental measurement and the SM theoretical prediction for the muon anomalous MDM, constrained by t…
The $μν$SSM, one of supersymmetric extensions of the Standard Model, introduces three right-handed neutrino superfields to solve the $μ$ problem and violates lepton number. Within framwork of the $μν$SSM, we investigate the lepton flavor violating (LFV) processes $Z\rightarrow l_i^\pm l_j^\mp$ with slepton flavor mixing. Simultaneously, we consider the LFV processes $l_j^-\rightarrow l_i^-γ$, $l_j^- \rightarrow l_i^- l_i^- l_i^+$ and muon conversion to electron in nuclei.
The $μν$SSM, one of supersymmetric extensions beyond the Standard Model, introduces three singlet right-handed neutrino superfields to solve the $μ$ problem and can generate three tiny Majorana neutrino masses through the seesaw mechanism. In this work, we investigate the rare decay process $\bar{B}\rightarrow X_sγ$ in the $μν$SSM, under a minimal flavor violating assumption for the soft breaking terms. Constrained by the SM-like Higgs with mass around 125 GeV, the numerical results show that the new physics can fit the experimental data for $\bar{B}\rightarrow X_sγ$ and further constrain the …
We have developed an efficient formulation for the study of the generic supersymmetric standard model, which admits all kind of R-parity violating terms. Using the formulation, we discuss all sources of fermion dipole moment contributions from R-parity violating, or rather lepton number violating, parametersand the constraints obtained. Stringent constraints comparable to those from neutrino masses are resulted in some cases.
The possibility to measure an electric dipole moment (EDM) of nuclei in the range $10^{-27} ÷10^{-32}$ $e \cdot cm$ in experiments for search of time-reversal violating generation of magnetic and electric fields is discussed.
The contribution of the R-parity violating trilinear couplings in the supersymmetric model to the fermion electric dipole moment is analyzed at the two-loop level. We show that in general, the Barr-Zee type contribution to the fermion electric dipole moment with the exchange of W and Z bosons is not small compared to the currently known photon exchange one with R-parity violating interactions. We will then give new upper bounds on the imaginary parts of R-parity violating couplings from the experimental data of the electric dipole moments of the electron and of the neutron. The effect due to b…
Charged lepton flavor violating processes are forbidden in the standard model (SM), hence the observation of charged lepton flavor transitions would represent a clear signal of new physics beyond the standard Model. In this work, we investigate some lepton flavor violating processes in the minimal supersymmetric extension of the SM with local $B-L$ gauge symmetry (B-LSSM). And including the corrections from some two loop diagrams to the anomalous dipole moments (MDM) of muon, we discuss the corresponding constraint on the relevant parameter space of the model. Considering the constraints from …
We propose to extract the electric and weak dipole moments of the top quark via $t\bar tγ$ and $t\bar t Z$ productions at the CERN LHC. With the large numbers of events available at the LHC, these dipole moments can be measured to the accuracy of $10^{-18}e cm$.
We study baryogenesis at the electroweak phase transition of the universe within the framework of the supersymmetric standard model (SSM) based on N=1 supergravity. This model contains a new source of CP violation in the mass-squared matrices for squarks, which could enable $t$ squarks to mediate the charge transport mechanism for generating baryon asymmetry. The same CP-violating source also induces the electric dipole moment (EDM) of the neutron at the one-loop level. If the new CP-violating phase is not suppressed, it is shown, the $t$-squark transport can lead to baryon asymmetry consisten…
We reexamine the R-parity violating contribution to the fermion electric and chromo-electric dipole moments (EDM and cEDM) in the two-loop diagrams. It is found that the leading Barr-Zee type two-loop contribution is smaller than the result found in previous works, and that EDM experimental data provide looser limits on RPV couplings.
In the CP violating supersymmetric extension of the standard model with local gauged baryon and lepton symmetries(BLMSSM), there are new CP violating sources which can give new contributions to the quark electric dipole moment (EDM). Considering the CP violating phases, we analyze the EDMs of the quarks c and t. We take into account the contributions from the one loop diagrams. The numerical results are analyzed with some assumptions on the relevant parameter space. The numerical results for the c and t EDMs can reach large values.
Considering the CP violating phases, we analyze the neutron electric dipole moment (EDM) in a CP violating supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries(BLMSSM). The contributions from the one loop diagrams and the Weinberg operators are taken into account. Adopting some assumptions on the relevant parameter space, we give the numerical results analysis. The numerical results for neutron EDM can reach $1.05\times 10^{-25}(e.cm)$, which is about the experimental upper limit.
We show how to determine the electric and weak dipole moments of the top quark simultaneously and independently from $e^+e^-\to t\bar t$ at $\sqrt{s}=500$ GeV NLC. To obtain the best accuracies with which the dipole moments can be measured, we apply the optimal observables to extract the CP violating effects and consider only purely hadronic, hadronic-leptonic final state events. Results with left- and right- handed longitudinal polarized as well as unpolarized electron beams are given. We find that with $50fb^{-1}$ integrated luminosity, the dipole moments can be measured to the accuracy of $…
It is shown that in the experiments for search of the EDM of an electron (atom, molecule) the T-odd magnetic moment induced by an electric field and the T-odd electric dipole moment induced by a magnetic field will be also measured. It is discussed how to distinguish these contributions.
We evaluate the Barr-Zee type two-loop level contribution to the fermion electric and chromo-electric dipole moments with sfermion loop in R-parity violating supersymmetric models. It is found that the Barr-Zee type fermion dipole moment with sfermion loop acts destructively to the currently known fermion loop contribution, and that it has small effect when the mass of squarks or charged sleptons in the loop is larger than or comparable to that of the sneutrinos, but cannot be neglected if the sneutrinos are much heavier than loop sfermions.
Using the present upper bound on the neutron electric dipole moment, we give an estimate for the upper limit of the CP-violating couplings of the eta(eta') to the nucleon. Using this result, we then derive constraints on the CP-violating eta(eta')-pi-pi couplings, which define the two-pion CP-violating decays of the eta and eta' mesons. Our results are relevant for the running and planned measurements of rare decays of the eta and eta' mesons by the GlueX Collaboration at JLab and the LHCb Collaboration at CERN.
Nonstandard CP violation in the Higgs sector can play an essential role in electroweak baryogenesis. We calculate the full two-loop matching conditions of the standard model, with Higgs Yukawa couplings to light quarks modified to include arbitrary CP-violating phases, onto an effective Lagrangian comprising CP-odd electric and chromoelectric light-quark (up, down, and strange) dipole operators. We find large isospin-breaking contributions of the electroweak diagrams. Using these results, we obtain significant constraints on the phases of the light-quark Yukawas from experimental bounds on the…
Perturbative QCD Prediction of the Hyperon EDM from CP-violating Dipole Interactions
Shandong Jianzhu University（山东建筑大学）；Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交大李政道研究所）；Shanghai Jiao Tong University（上海交通大学）；Henan Normal University（河南师范大学）；Chinese Academy of Sciences（中国科学院）；University of Jyväskylä（于韦斯屈莱大学）；Helsinki Institute of Physics（赫尔辛基物理研究所）
An effective anomalous CP-violating Z-gamma-gamma coupling can give rise to observable CP-odd effects in gamma gamma -> t bar{t}. We study certain asymmetries in the decay lepton distributions in gamma gamma -> t bar{t} arising from top decay in the presence of a CP-violating Z-gamma-gamma coupling as well as a top-quark electric dipole coupling. We find that a photon linear collider with geometric luminosity of 20 fb^{-1} can put limits of the order of 0.1 on the imaginary part of the CP-violating anomalous Z-gamma-gamma coupling using these asymmetries.
In a bent crystal the $P$-odd effect of short-lived baryon spin rotation could imitate spin rotation caused by assumed EDM. Use of different behavior of $P$-odd and $T$-odd spin rotations at crystal turning around the direction of particle momentum makes it possible to exclude $P$-odd rotation contribution, when measuring short-lived baryons EDM. Subtraction of the measurement results for angle ranges $φ$ and $φ+ π$ from each other enables measuring $T$-odd rotation at scattering of negatively charged beauty and neutral baryons by axes of unbent crystal.
Electric dipole moments are sensitive probes of new phases in the Higgs Yukawa couplings. We calculate the complete two-loop QCD anomalous dimension matrix for the mixing of CP-odd scalar and tensor operators and apply our results for a phenomenological study of CP violation in the bottom and charm Yukawa couplings. We find large shifts of the induced Wilson coefficients at next-to-leading-logarithmic order. Using the experimental bound on the electric dipole moment of the neutron, we update the constraints on CP-violating phases in the bottom and charm quark Yukawas.
We analyze two-loop gluino corrections to the neutron electric dipole moment (EDM) in the minimal supersymmetry extension of the standard model (MSSM). The dependence of two-loop corrections on the relevant CP violating phases differs from that of the one-loop contributions, and there is a region in the parameter space where the two-loop contributions are comparable with the one-loop contributions. Our numerical results show that the two-loop corrections can be as large as 30% of the one-loop results.
We discuss CP asymmetries in $B^0$-meson decays and \BsBs mixing within the framework of the supersymmetric standard model (SSM). It is shown that \BdBd and \KK mixings could receive sizable new contributions through box diagrams mediated by the charginos and charged Higgs bosons. This implies that the CP-violating phase of the Cabibbo-Kobayashi-Maskawa matrix may have a value which is different from the one predicted by the standard model (SM). The value of the CP-violating phase affects the amounts of the CP asymmetries and \BsBs mixing. We examine predictions for these quantities in both th…
We analyze the neutron electric dipole moment (EDM) in the Minimal Supersymmetric Model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the 2-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings ${λ'}_{ijk}$ and $λ_{ijk}$ due to the virtual b-loop or tau-loop.
We calculate the CP-violating electric and weak dipole form factors of the top quark and the tau lepton in models with scalar leptoquarks coupling only to the third generation of quarks and leptons. We obtain numerical values of the real and imaginary parts of these form factors at various energies for different values of leptoquark masses and couplings. The existing limits on the tau electric and weak dipole form factors allows us to put a limit on the masses and couplings of such leptoquarks and therefore on the top electric and weak dipole form factors. We also discuss constraints on the fo…
We calculate the electric dipole moment of electron using the experimental result of muon electric dipole moment and upper limit of the BR(μ--> eγ) in the framework of the general two Higgs doublet model. Our prediction is 10^{-32} e-cm, which lies in the experimental current limits. Further, we obtain constraints for the Yukawa couplings \barξ^{D}_{N,τe} and \barξ^{D}_{N,τμ}. Finally we present an expression which connects the BR(τ\to μγ) and the electric dipole moment of τ-lepton and study the relation between these physical quantities.
CP-violating asymmetries due to a possible electric dipole interaction of the top quark in the production and subsequent decay of top quark-top antiquark pair in photon-photon collisions are studied. The asymmetries defined can be used to determine the imaginary part of the electric dipole form factors. A gamma-gamma collider with photon beams generated from laser back-scattering off electron beams with an integrated geometric luminosity of 20 fb^{-1} can put a limit of the order of 10^{-17} e cm on the imaginary part of the electric dipole form factor of the top quark if the electron beams ha…
We investigate electric dipole moments (EDMs) in a CP-violating minimal supersymmetric standard model with the Bino-like neutralino dark matter (DM) annihilating through the heavy Higgs funnel. Motivated by the current experimental results, in particular, the measured mass of the standard model-like Higgs boson, we consider a mass spectrum with stop masses of about 10 TeV. For the other sfermions, we consider masses of about 100 TeV. We show that CP-violating phases of the order of ten degrees in gaugino and Higgsino mass parameters are consistent with the current bound by EDMs of the electron…
We report the first fully general numerical calculation of the neutron and electron dipole moments, including the seven significant phases. We find that there are major regions in the parameter space where none of the phases are required to be small, contrary to the conventional wisdom. The electric dipole moments (EDM's) do provide useful constraints, allowing other regions of parameter space to be carved away. We keep all superpartner masses light so agreement with experimental limits arises purely from interesting relations among soft breaking parameters.
We investigate the muon anomalous magnetic dipole moment (MDM), the muon electric dipole moment (EDM) and the lepton-flavour-violating decays of the $τ-$lepton, $τ\to μγ$ and $τ\to 3μ$, in the CP-violating Minimal Supersymmetric Standard Model (MSSM) with nonuniversal soft-supersymmetry breaking. We evaluate numerically the muon EDM and the branching ratios $B(τ\to μγ)$ and $B(τ\to 3μ)$, after taking into account the experimental constraints from the electron EDM and muon MDM. Upon imposition of the experimental limits on our theoretical predictions for the aforementioned branching ratios and …
It has been shown that CP violating electron-nucleon and nucleon-nucleon interactions can induce atomic electric dipole moments and are therefore constrained from experimental data. We show that using the experimental upper bounds on neutron and electron electric dipole moments, one can also obtain constraints, in some cases better ones, on these interactions. In addition stringent constraints can also be obtained for muon-quark and tauon-quark four-fermion CP violating interactions, which cannot be constrained from atomic electric dipole moment experiments.
We consider the implications of experimental limits on the permanent electric dipole moment (EDM) of the electron and neutron for possible new parity-conserving (PC) time-reversal violating (TV) interactions. We show that the constraints derived from one-loop contributions to the EDM exceed previously reported two-loop limits by more than an order of magnitude and imply a lower bound on the new TVPC mass scale $\lamtv$ of 100 TeV for new TVPC strong interactions. These results imply a value of $10^{-15}$ or smaller for the ratio of low-energy TVPC matrix elements to those of the residual stron…
The supersymmetric standard model (SSM) has a CP-violating phase in its gauge-Higgs sector. This new source of CP violation induces the electric dipole moments (EDMs) of the neutron and electron at the one-loop level. The same CP-violating phase generates the EDM of the $W$ boson through one-loop diagrams mediated by the charginos and neutralinos, which leads to the EDMs of the neutron and electron at the two-loop level. We discuss these EDMs, assuming that the CP-violating phase has the magnitude of order 0.1--1 which may be suggested from the baryon asymmetry of the universe. Even at the two…
In this talk I discuss some aspects of the study of electric dipole moments (EDMs) of the fermions, in the context of R-parity violating (\rpv) Supersymmetry (SUSY). I will start with a brief general discussion of how dipole moments, in general, serve as a probe of physics beyond the Standard Model (SM) and an even briefer summary of \rpv SUSY. I will follow by discussing a general method of analysis for obtaining the leading fermion mass dependence of the dipole moments and present its application to \rpv SUSY case. Then I will summarise the constraints that the analysis of $e,n$ and $Hg$ EDM…
We discuss the effect of CP violation in the aligned scenario of the general two-Higgs-doublet model, in which the Higgs potential and the Yukawa interaction provide additional CP-violating phases. An alignment is imposed to the Yukawa interaction in order to avoid dangerous flavor changing neutral currents. The Higgs potential is also aligned such that the coupling constants of the lightest Higgs boson, which is identified as the discovered Higgs boson with the mass of 125 GeV, are the same as those of the standard model. In general, CP-violating phases originated by the Yukawa interaction an…
In the presence of an electric dipole coupling of $t \bar t$ to a photon, and an analogous ``weak" dipole coupling to the $Z$, $CP$ violation in the process $e^+e^- \rightarrow t \bar t$ leads to the polarization of the top and anti-top. This polarization can be analyzed by studying the energy and angular distributions of a decay charged lepton (anti-lepton) when the top (anti-top) decays leptonically. We have obtained analytic expressions for these distributions when either $t$ or $\overline t$ decays leptonically. We study two types of simple $CP$-violating angular asymmetries which do not n…
The magnetic dipole moment (MDM) and the electric dipole moment (EDM) of leptons are calculated under the assumption of lepton flavor violation (LFV) induced by spin-1 unparticles with both vector and axial-vector couplings to leptons,including a CP-violating phase. The experimental limits on the muon MDM and LFV process such as the decay l_i->i_jl_kl_k are then used to constrain the LFV couplings for particular values of the unparticle operator dimension d_U and the unparticle scale Λ_U, assuming that LFV transitions between the tau and muon leptons are dominant. It is found that the current …
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…
The question of CP violating phases in supersymmetry and electric dipole moments (EDMs) is considered within the framework of supergravity grand unification (GUT) models with a light ($\stackrel{<}{\sim}$1 TeV) mass spectrum. In the minimal model, the nearness of the t-quark Landau pole automatically suppresses the t-quark cubic soft breaking phase at the electroweak scale. However, current EDM data require the quadratic soft breaking phase to be small at the electroweak scale unless tan$β$ is small (tan$β\stackrel{<}{\sim}$3), and the EDM data combined with the requirement of electroweak symm…
We study two simple $CP$-violating asymmetries of leptons coming from the decay of $t$ and $øt$ in $e^+e^- \ra \tt$, which do not need the full reconstruction of the $t$ or $øt$ for their measurement. They can arise when the top quark possesses nonzero electric and weak dipole form factors in the couplings to the photon and $Z$, respectively. Together, these two asymmetries can help to determine the electric and weak dipole form factors independently. If longitudinal beam polarization is available, independent determination of form factors can be done by measuring only one of the asymmetries. …
Electric dipole moments of atoms can arise from P-odd and T-odd electron--nucleon couplings. This work studies a general class of dimension-six electron--nucleon interactions mediated by Lorentz-violating tensors of ranks ranging from $1$ to $4$. The possible couplings are listed as well as their behavior under C, P, and T, allowing us to select the couplings compatible with electric-dipole-moment physics. The unsuppressed contributions of these couplings to the atom's hamiltonian can be read as equivalent to an electric dipole moment. The Lorentz-violating coefficients' magnitudes are limited…
In the context of general Minimal Supersymmetric Standard Model (MSSM), new sources for Lepton Flavor Violation (LFV) as well as CP-violation appear. We show that in the presence of LFV sources, the electric dipole moment of the electron ($d_e$) can receive new contributions. In particular, $d_e$ can receive a significant contribution at one loop level from the phase of the trilinear $A$-term of the staus, $ϕ_{A_τ}$. We discuss how we can derive information on $ϕ_{A_τ}$ by combining the information on $d_e$ with that on the LFV decay modes of the $τ$ lepton. We then discuss if this approach ca…
We argue that the large-$\Nc$ behaviour of the Yukawa couplings in the Skyrme model involves issues more subtle than the vanishing of linear fluctuations needed for classical stability of the skyrmion. The chiral fluctuations about the skyrmion must be quantized in order to reach a conclusion. An improved quantization procedure allows us to confront this question directly. The pion-nucleon coupling constants $\gcup$ (CP conserving) and $\bgcup$ (CP violating) are calculated in the large-$\Nc$, three-flavour Skyrme model by direct evaluation of the leading matrix elements appearing in the LSZ r…
The asymmetries ${\cal A}_k \equiv [Γ(\twddec) -Γ(\tbwddec)] /[Γ(\twddec) + Γ(\tbwddec)]$ in the partial widths of the top quark decays are discussed within the Standard Model (SM), the Two-Higgs-Doublet Model (2HDM) and supersymmetric extensions of the SM (SSM). The leading contributions to these asymmetries in the SM and in the 2HDM are induced by the up-type quark self-energy diagrams and are found to be very small. However, in the SSM, the asymmetry ${\cal A}_b$ can be substantial, ${\cal O}(α_{QCD})$, provided the CP-violating phase of gluino-top-stop couplings is not suppressed. Within t…
The possibility of cancelation between different contributions to d_e, d_n and d_{Hg} has been reconsidered with special emphasis on the region that is phenomenologically interesting (intermediate values of \tan βand sub-TeV sfermion masses). It is found that in the range favored by electroweak baryogenesis (\it i.e., |μ|\simeq M_1 or |μ|\simeq M_2), \sin [θ_μ+θ_{M_1}]\sim 1 can be compatible with the EDM bounds even for slepton masses below 500 GeV. Such large values of the phases promise a successful electroweak baryogenesis. The possibility of large CP-odd effects at linear collider has als…
We analyze the Lepton Flavor Violating (LFV) Higgs decay h -> tau mu in three supersymmetric models: Minimal Supersymmetric Standard Model (MSSM), Supersymmetric Seesaw Model (SSM), and Supersymmetric B-L model with Inverse Seesaw (BLSSM-IS). We show that in generic MSSM, with non-universal slepton masses and/or trilinear couplings, it is not possible to enhance BR(h -> tau mu) without violating the experimental bound on the BR(tau -> mu gamma). In SSM, where flavor mixing is radiatively generated, the LFV process mu -> e gamma strictly constrains the parameter space and the maximum value of B…
In the $μν$SSM, the presence of $R$-parity violating couplings involving right-handed (RH) neutrinos solves simultaneously the $μ$- and $ν$-problems. We explore extensions of the $μν$SSM adding a $U(1)'$ gauge group, which provides the RH neutrinos with a non-vanishing charge. In these models, dubbed U$μν$SSM, the anomaly cancellation conditions impose the presence of exotic quarks in the spectrum that are vector-like under the standard model (SM) gauge group: either three pairs $SU(2)$ quark singlets, or a pair of quark singlets together with a pair of quark doublets. Several extra singlets u…
