We compute the one-loop running of the dimension-six CP-even Higgs operators in the Standard Model effective field theory involving the right-handed component of the would-be Dirac neutrinos. We discuss the implications of a large Dirac neutrino magnetic dipole moment. In particular, we demonstrate that a neutrino magnetic moment explaining the recent XENON1T excess induces Higgs and $Z$ invisible decays with branching ratios in the range $[10^{-18}, 10^{-12}]$. These numbers are unfortunately beyond the reach of current and near future facilities.
We present results from analytic solutions to the running coupling, full next-to-leading order, and collinearly improved next-to-leading order Balitsky-Kovchegov equations in the saturation region with the smallest dipole size QCD running coupling prescription. The analytic results of the $S$-matrix of the latter two equations show that the $\exp(-\mathcal{O}(Y^{3/2}))$ rapidity dependence of the solutions are replaced by $\exp(-\mathcal{O}(Y))$ dependence once the running coupling prescription is switched from parent dipole to the smallest dipole prescription, which indicate that the $S$-matr…
We study the lepton electric dipole moments in the split fermion scenario, in the two Higgs doublet model, where the new Higgs scalars are localized around the origin in the extra dimension, with the help of the localizer field. We observe that the numerical value of the electron (muon, tau) electric dipole moment is at the order of the magnitude of 10^{-31} (10^{-24}, 10^{-22}) (e-cm) and this quantity is sensitive the new Higgs localization in the extra dimension.
We study the Electric Dipole moment of b quark in the general two Higgs Doublet model (model III) and three Higgs Doublet model with O(2) symmetry in the Higgs sector. We analyse the dependency of this quantity to the new phase coming from the complex Yukawa couplings and masses of charged and neutral Higgs bosons. We see that the Electric Dipole moment of b quark is at the order of 10^{-20} e cm, which is an extremely large value compared to one calculated in the SM and also two Higgs Doublet model (model II) with real Yukawa couplings.
The complete set of Higgs-boson two-loop contributions to electric dipole moments of the electron and neutron is calculated in the minimal supersymmetric standard model. The electric dipole moments are induced by CP-violating trilinear couplings of the `CP-odd' and charged Higgs bosons to the scalar top and bottom quarks. Numerical estimates of the individual two-loop contributions to electric dipole moments are given.
We study the the effects of non-universal extra dimensions on the electric dipole moments of fermions in the two Higgs doublet model. We observe that the t quark and b quark electric dipole moments are sensitive to the extra dimensions, however, in the case of charged lepton electric dipole moments, this sensitivity is relatively weak.
We predict the charged lepton electric dipole moments in the split fermion scenario in the framework of the two Higgs doublet model. We observe that the numerical value of the muon (tau) electric dipole moment is at the order of the magnitude of $10^{-22} (e-cm)$ ($10^{-20} (e-cm)$) and there is an enhancement in the case of two extra dimensions, especially for the tau lepton electric dipole moment.
We compute the complete set of Higgs-mediated chargino-neutralino two-loop contributions to the electric dipole moments (EDMs) of the electron and neutron in the minimal supersymmetric standard model (MSSM). We study the dependence of these contributions on the parameters that govern CP-violation in the MSSM gauge-gaugino-Higgs-Higgsino sector. We find that contributions mediated by the exchange of W H^\pm and Z A^0 pairs, where H^\pm and A^0 are the charged and CP-odd Higgs scalars, respectively, are comparable to or dominate over those mediated by the exchange of neutral gauge bosons and CP-…
We study the electric and chromo electric dipole moment of top quark in the general two Higgs Doublet model (model III). We analyse the dependency of this quantity to the new phases coming from the complex Yukawa couplings and masses of charged and neutral Higgs bosons. We observe that the electric and chromo elecric dipole moments of top quark are at the order of 10^{-21} e cm and 10^{-20} g_s cm, which are extremely large values compared to ones calculated in the SM and also two Higgs Doublet model with real Yukawa couplings.
We study the explicit CP violation of the Higgs sector in the next--to--minimal supersymmetric model with a gauge singlet Higgs field. Our numerical predictions show that electric dipole moment of electron lies around the present experimental upper limits. The mass of the lightest Higgs boson is quite sensitive to the CP violating phases in the theory. It is observed that as the vacuum expectation value of the singlet gets higher values, CP violation increases.
We perform a comprehensive study of the dominant two- and higher-loop contributions to the $^{205}$Tl, neutron and muon electric dipole moments induced by Higgs bosons, third-generation quarks and squarks, charginos and gluinos in the Minimal Supersymmetric Standard Model (MSSM). We find that strong correlations exist among the contributing CP-violating operators, for large stop, gluino and chargino phases, and for a wide range of values of $\tanβ$ and charged Higgs-boson masses, giving rise to large suppressions of the $^{205}$Tl and neutron electric dipole moments below their present experim…
The electric and weak electric dipole form factors for heavy fermions are calculated in the context of the most general two-Higgs-doublet model (2HDM). We find that the large top mass can produce a significant enhancement of the electric dipole form factor in the case of the b and c quarks. This effect can be used to distinguish between different 2HDM scenarios.
The running of the Top quark mass is considered in the nonperturbative framework of the Schwinger-Dyson equation. Based on the input of physical pole mass meassured at the Tevatron the method provides the resulting mass function which is almost constant at low spacelike and timelike scales. The skeleton loops including Standard Model Higgs and gluons are taken into account. The dominant two-loop skeleton contribution with triplet Higgs interaction is considered in addition to one loop dressed approximation of the top quark self-energy.
In this paper we study the neutron electric dipole moment (EDM) due to Higgs boson exchange in Left-Right symmetric models. In pseudo-manifest Left-Right symmetric models, the neutral Higgs contribution is smaller than that from the charged Higgs. The charged Higgs contribution at the two loop level can be as large as the experimental upper bound. In non (pseudo) manifest Left-Right symmteric models, the neutral Higgs exchange contribution can reach the experimental upper bound. The Higgs exchange contributions can be more important than the ones from W-boson exchange due to $W_L - W_R$ mixing…
The Higgs sector which is extended from the standard model could generally become an origin of CP violation. In the model with two doublet and one triplet Higgs fields on SU(2) symmetry, we study the electric dipole moment (EDM) of the electron whose non-vanishing value has not yet been established experimentally. The Higgs potential is assumed to be consistent with supersymmetric theory, though supersymmetric particles are not taken into consideration explicitly. While the parameter values of the model are severely constrained by the properties of the observed Higgs boson, certain ranges lead…
The dual Higgs model is reformulated in terms of two-point Wightman functions with the equations of motion involving higher derivatives. In the system of the test color charges an analytic expression for the string tension is derived.
The leading contributions to the electron (or muon) electric dipole moment due to CP violation in the charged Higgs sector are at the two-loop level. A careful analysis of the model-independent contribution is provided. We also consider specific scenarios to demonstrate how charged Higgs sector CP violation can naturally give rise to large electric dipole moments. Numerical results show that the electron electric dipole moment in such models can lie at the experimentally accessible level.
The Schwinger-Dyson equation for the quark self-energy is solved for the case of the third and fourth quark generations. The exchanges of standard model gluons and Higgs bosons are taken into account. It is found that Higgs boson exchange dominates quark self-energy in the ultraviolet region for sufficiently large input quark masses, causing the running quark propagator mass to increase with energy-scale. No running of the quark mixing angles is found for input quark masses up to and including 500 GeV.
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.
The littlest Higgs model with T-parity, which is called $LHT$ model, predicts the existence of the new particles, such as heavy top quark, heavy gauge bosons, and mirror fermions. We calculate the one-loop contributions of these new particles to the top quark chromomagnetic dipole moment $(CMDM)$ $ΔK$. We find that the contribution of the $LHT$ model is one order of magnitude smaller than the standard model prediction value.
The effect of the "chromo-electric" dipole moment on the electric dipole moment(EDM) of the neutron is studied in the two-Higgs-doublet model. The Weinberg's operator $O_{3g}=GG\t G$ and the operator $O_{qg}=\bar qσ\t Gq$ are both investigated in the cases of $\tan\b\gg 1$, $\tan\b\ll 1$ and $\tan\b\simeq 1$. The neutron EDM is considerably reduced due to the destructive contribution with two light Higgs scalars exchanges.
We study the viability of electroweak baryogenesis in a two Higgs doublet model scenario augmented by vector-like, electroweakly interacting fermions. Considering a limited, but illustrative region of the model parameter space, we obtain the observed cosmic baryon asymmetry while satisfying present constraints from the non-observation of the permanent electric dipole moment (EDM) of the electron and the combined ATLAS and CMS result for the Higgs boson diphoton decay rate. The observation of a non-zero electron EDM in a next generation experiment and/or the observation of an excess (over the S…
In this work we study the anomalous top quark-gluon couplings Chromoelectric Dipole Moment (CEDM) and Chromomagnetic Dipole Moment (CMDM) in a general THDM with CP violation. We find that this model provides an important contribution from the $Y_{tt}$ Yukawa coupling that needs to be taken into account. The CMDM and CEDM obtained are $-0.03<Δ\tilde{k} < 0.005}$ and $|Δ\tilde{d}| < 0.005$, respectively.
We calculate the chromomagnetic dipole moment of the top quark, $\hatμ_t$, in the context of the Bestest Little Higgs model. This extension of the Standard Model aims to solve the hierarchy problem without fine tuning, by introducing one-loop corrections to the Higgs boson mass through heavy top quark partners and heavy gauge bosons. We found that the largest resulting value for the chromomagnetic is $\hatμ_t\sim 10^{-5}$ and the lowest is around $10^{-6}$, mainly due to the Higgs boson of the Standard Model, which couples to both the top quark of the Standard Model and its heavy partners. Als…
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 this paper we propose a method to compute the running top-Yukawa coupling in supersymmetric models with heavy mass spectrum based on the "running" and "decoupling" procedure. In order to enable this approach we compute the two-loop SUSY-QCD radiative corrections required in the decoupling process. The method has the advantage that large logarithmic corrections are automatically resummed through the Renormalization Group Equations. As phenomenological application we study the effects of this approach on the prediction of the lightest Higgs boson mass at three-loop accuracy. We observe a sign…
The running BFKL equation gives rise to a series of moving poles in the complex j-plane. Corresponding eigenfunctions (color dipole cross sections) are the oscillating functions of the color dipole size $r$. The first nodes for all sub-leading solutions (color dipole cross sections) accumulate at $r_1\sim 0.1 fm$. Therefore the processes dominated by the dipole sizes $r\sim r_1$ are free of sub-leading BFKL corrections. A practically important example - the leptoproduction of charm. In a wide range of $Q^2$ the calculated $F_2^{cc}(x,Q^2)$ is exhausted by the leading BFKL pole and gives a perf…
We study the muon magnetic dipole moment and the Higgs mass in the framework of the supersymmetric SU(5) models. In this analysis, all the relevant parameters in the Lagrangian are taken to be free; in particular, assumption of the universal scalar mass is not adopted. Negative search for the Higgs boson at the LEP II experiment sets an important constraint on the supersymmetric contribution to the muon magnetic dipole moment a_μ(SUSY). It is shown that, for a fixed value of the lightest Higgs mass, the maximum possible value of a_μ(SUSY) becomes significantly larger in the general SU(5) case …
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…
A natural solution to the hierachy problem of the standard model is to assume new physics to appear at the TeV scale. We parametrize the effects of this new physics in terms of an effective lagrangian and examine its impacts on electroweak baryogenesis. We point out that with such an effective lagrangian successful electroweak baryogenesis implies: i) Higgs boson lies within the reach of LEP II; ii)electric dipole moments of electron and neutron are detectable in the near future.
In the framework of a two Higgs doublet model type I and type II, we calculate limits on neutrino masses for the different types of neutrinos, by using the experimental bounds on their magnetic dipole moments. This is carried out by analyzing diagrams of Cherenkov neutrino decays with a charged Higgs into the loop, coming from the two Higgs doublet model (2HDM). Such constraints are translated into allowed regions in the free parameters of the models, for each neutrino flavor. The analysis was performed by sweeping the charged Higgs mass between (100-900)GeV and taking into account the experim…
I consider neutron electric dipole moment contributions induced by flavor changing Standard Model Higgs boson couplings to quarks. Such couplings might stem from non-renormalizable $SU(2)_L \times U(1)_Y$ invariant Lagrange terms of dimension six, containing a product of three Higgs doublets. Previously one loop diagrams with such couplings were considered in order to constrain {\it quadratric} expressions of Higgs flavor changing couplings to quarks. In the present paper the analysis is extended to the two loop level, where there are diagrams for electric dipole moments of quarks with a flavo…
We study the effect of the "chromo-electric" dipole moment on the electric dipole moment(EDM) of the neutron in the two Higgs doublet model. We systematically investigate the Weinberg's operator $O_{3g}=GG\t G$ and the operator $O_{qg}=\bar qσ\t Gq$, in the cases of $\tan\b\gg 1$, $\tan\b\ll 1$ and $\tan\b\simeq 1$. It is shown that $O_{sg}$ gives the main contribution to the neutron EDM compared to the other operators, and also that the contributions of $O_{ug}$ and $O_{3g}$ cancel out each other. It is pointed out that the inclusion of second lightest neutral Higgs scalar adding to the light…
From the total cross section for the reaction $e^+e^-\to τ^+τ^-γ$ at the $Z_1$ pole and in the framework of a simplest little Higgs model (SLHM), we get a limit on the characteristic energy scale of the model $f$, $f \geq 5.4$ $TeV$, which in turn induces bounds on the electromagnetic and weak dipole moments of the tau-lepton. Our bounds on the electromagnetic moments are consistent with the bounds obtained by the L3 and OPAL collaborations for the reaction $e^+e^-\to τ^+τ^-γ$. We also obtained bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the …
We study the electric dipole moments(EDM) of the neutron and the electron in the two-Higgs-doublet model, in the case that $CP$ symmetry is violated maximally in the neutral Higgs sector. We take account of the Weinberg's operator $O_{3g}=GG\t G$ as well as the operator $O_{qg}=\bar qσ\tilde Gq$ for the neutron, and the Barr-Zee diagrams for the electron. It is found that the predicted neutron EDM could be considerably reduced by the destructive contribution of the two Higgs scalars to get the lower value than the experimental bound. As to the electron EDM, the predicted value is smaller in on…
Supersymmetric loop corrections induce potentially large CP-violating couplings of the Higgs bosons to nucleons and electrons that do not vanish in the limit of heavy superpartners. The Higgs-mediated CP-odd four-fermion operators are enhanced by tan^3 beta and induce electric dipole moments of heavy atoms which exceed the current experimental bounds for the electroweak scale Higgs masses and tan beta > 10. If only the first two sfermion generations are heavy, the Higgs-mediated contributions typically dominate over the Barr-Zee type two-loop diagrams at tan beta > 30.
In this paper, using the Bestest Little Higgs Model (BLHM) we calculate at the one-loop level the contributions to the Anomalous Magnetic Dipole Moment (AMDM) and Anomalous Weak Magnetic Dipole Moment (AWMDM) of the tau-lepton. The implications from this model are study, emphasizing the contributions of the new physics induced by the new scalar and vector bosons of the BLHM: $S_i=H_0, A_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}$, and $V_i=Z', W'$, because these quantify the new physics. With these new contributions we estimated bounds on both the real and imaginary parts of the AMDM and AW…
We propose a CP-violating source in the charged Higgs sector of a 3-Higgs Doublet Model (3HDM) that will contribute to three CP-asymmetry observables for low energy processes. In the context of such a 3HDM, a measurement of one of the specific asymmetry observables (i.e., $\bar{B} \to X_{s+d} γ$) could obtain up to 2.5% or more, which would give a 5$σ$ evidence for physics Beyond the SM (BSM) from the full BELLE II data set. In addition to these CP-violating observables, the current measurements of Electron Dipole Moments (EDMs) constrain the available parameter region of the CP-violating 3HDM…
We study the neutron electric dipole moment (EDM) in a five dimensional SU(3) gauge-Higgs unification compactified on M^4 \times S^1/Z_2 space-time including a massive fermion. We point out that to realize the CP violation is a non-trivial task in the gauge-Higgs unification scenario and argue how the CP symmetry is broken spontaneously by the VEV of the Higgs, the extra space component of the gauge field. We emphasize the importance of the interplay between the VEV of the Higgs and the Z_2-odd bulk mass term to get physically the CP violation. We then calculate the one-loop contributions to t…
I consider contributions to the neutron electric dipole moment within Two Higgs Doublet Models which allow for small flavor changing neutral Higgs couplings. In a previous paper, I considered flavor changing interactions for the Standard Model Higgs boson to first order in the flavor changing coupling. In that paper I found that the obtained value of the neutron electric dipole moment were below the present experimental limit, given previous restrictions on such couplings. Because this was an effective theory, the result depended on an ultraviolet cut off $Λ$, parametrized as $ln(Λ^2)$. In the…
Starting from the dipole representation of small-$x$ evolution we implement the running of the coupling in a self-consistent way. This results in an evolution equation for the dipole density in Borel $(b)$ space. We show that the Borel image of the dipole density is analytic in the neighbourhood of $b=0$ and that it is equal to the BFKL solution at $b=0$. We study the Borel singularity structure of the dipole cascade emanating from a virtual photon at small $x$ and find a branch cut on the positive $b$-semiaxis starting at $b=1/ β_0$. This indicates the presence of $1/Q^2$ power corrections to…
The contributions of a second Higgs doublet to the electron electric dipole moment near the heavy Higgs decoupling limit are determined within an effective field theory framework. In models that satisfy the Glashow-Weinberg condition, the leading contributions in this limit at effective dimension six are shown to come from two-loop Barr-Zee diagrams that include the Standard Model-like Higgs boson. Additional diagrams that include heavy Higgs bosons are sub-leading and contribute only at effective dimension eight near the decoupling limit. This simplification implies that to leading order in t…
Complete two-loop Yukawa-induced running of the Higgs-gluon coupling in SMEFT
Karlsruhe Institute of Technology (KIT)（卡尔斯鲁厄理工学院）；Università degli Studi di Padova（帕多瓦大学）；Istituto Nazionale di Fisica Nucleare, Sezione di Padova（意大利国家核物理研究所帕多瓦分部）
Certain anomalous fermion-gauge boson couplings, such as the flavor diagonal anomalous color magnetic (CMDM) and color electric (CEDM) dipole moments of quarks are not fully gauge invariant under the SM. Restoring gauge invariance with an elementary Higgs doublet implies that they also contribute to Higgs boson production at the LHC and we study the corresponding constraints that can be placed on them. In a similar manner we study the constraints that can be placed on the $τ$-lepton anomalous magnetic moment, electric dipole moment, weak dipole moments, and dimension eight gluonic couplings at…
Physics beyond the standard model (SM) can be parameterized with an effective Lagrangian that respects the symmetries of the standard model and contains many operators of dimension six. We consider the subset of these operators that is responsible for flavor diagonal anomalous color magnetic (CMDM) and electric (CEDM) dipole couplings between quarks and gluons. Invariance of these operators under the SM implies that they contribute to Higgs boson production at the LHC and we study the corresponding constraints that can be placed on them. For the case of the top-quark we first review constraint…
In several frameworks for leptons-sectors of two Higgs doublet models, we calculate the magnetic dipole moment for the different flavor types of neutrino. Computations are carried out by assuming a normal hierarchy for neutrino masses, and analyzing the process $ν\rightarrow νγ$ with a charged Higgs boson into the loop. The analysis was performed by sweeping the charged Higgs mass and taking into account the experimental constraints for relevant parameters in Two Higgs Doublet Models with and without flavor changing neutral currents; obtaining magnetic dipole moments close to the experimental …
Flavour- and CP-violating electromagnetic or chromomagnetic dipole operators in the quark sector are generated in a large class of new physics models and are strongly constrained by measurements of the neutron electric dipole moment and observables sensitive to flavour-changing neutral currents, such as the $B\to X_sγ$ branching ratio and $ε'/ε$. After a model-independent discussion of the relevant constraints, we analyze these effects in models with partial compositeness, where the quarks get their masses by mixing with vector-like composite fermions. These scenarios can be seen as the low-en…
We study how the recent ATLAS and CMS Higgs mass bounds affect the renormalization group running of the physical parameters in universal extra dimensions. Using the running of the Higgs self-coupling constant, we derive bounds on the cutoff scale of the extra-dimensional theory itself. We show that the running of physical parameters, such as the fermion masses and the CKM mixing matrix, is significantly restricted by these bounds. In particular, we find that the running of the gauge couplings cannot be sufficient to allow gauge unification at the cutoff scale.
In this work, we make the first study of electroweak baryogenesis (EWBG) based on the LHC data in the CP-violating next-to-minimal supersymmetric model (NMSSM) where a strongly first order electroweak phase transition (EWPT) is obtained in the general complex Higgs potential. With representative benchmark points which pass the current LEP and LHC constraints, we demonstrate the structure of EWPT for those points and how a strongly first order EWPT is obtained in the complex NMSSM where the resulting gravitational wave production properties are found to be within the reaches of future space-bas…
We analyze CP-violating effects in both Electric Dipole Moment (EDM) measurements and future analyses at the Large Hadron Collider (LHC) assuming a Two-Higgs-Doublet Model (2HDM) with "soft" CP-violation. Our analysis of EDMs and current LHC constraints shows that, in the case of a 2HDM Type II and Type III, an $\mathcal{O}(0.1)$ CP-violating phase in the Yukawa interaction between $H_1$ (the $125~\textrm{GeV}$ Higgs boson) and fermions is still allowed. For these scenarios, we study CP-violating effects in the neutron EDM and $t\bar{t}H_1$ production at the LHC. Our analysis shows that such a…
The electric dipole moment of the muon ($d_μ$) is evaluated in a two Higgs doublet model with a softly broken discrete symmetry. The leading contributions from both one loop and two loop diagrams are considered. For $\tanβ\equiv |v_2|/|v_1|$ close to one, contributions from two loop diagrams involving the $t$ quark and the $W$ boson dominate; while for $\tanβ\agt 10$, contributions from two loop diagrams involving the $b$ quark and the $τ$ lepton are dominant. In these two regions, $d_μ\approx (m_μ/m_e) d_e$. For $8 \agt \tanβ\agt 4$, significant cancellation occurs among the contributions fro…
The Landau gauge Schwinger-Dyson Equation for the quark self-energy is solved in the quenched ladder approximation for several cases of one- and two-quark-generations. The exchanges of Standard Model gluons and Higgs bosons are taken into account. It is found that Higgs boson exchange dominates the quark self-energy for sufficiently large input quark masses (>75 GeV), causing the running quark propagator mass to increase with energy-scale. The running of the quark mixing angles is also considered. No running of the quark mixing angles is found, to one part in a billion, for input quark masses …
