We consider a non-Abelian dark SU(2)$_{\rm D}$ model where the dark sector couples to the Standard Model (SM) through a Higgs portal. We investigate two different scenarios of the dark sector scalars with $Z_2$ symmetry, with Higgs portal interactions that can introduce mixing between the SM Higgs boson and the SM singlet scalars in the dark sector. We utilize the existing collider results of the Higgs signal rate, direct heavy Higgs searches, and electroweak precision observables to constrain the model parameters. The $\text{SU(2)}_{\text{D}}$ partially breaks into $\text{U(1)}_{\text{D}}$ gauge group by the scalar sector. The resulting two stable massive dark gauge bosons and pseudo-Goldstone bosons can be viable cold dark matter candidates, while the massless gauge boson from the unbroken $\text{U(1)}_{\text{D}}$ subgroup is a dark radiation and can introduce long-range attractive dark matter (DM) self-interaction, which can alleviate the small-scale structure issues. We study in detail the pattern of strong first-order phase transition and gravitational wave (GW) production triggered by the dark sector symmetry breaking, and further evaluate the signal-to-noise ratio for several proposed space interferometer missions. We conclude that the rich physics in the dark sector may be observable with the current and future measurements at colliders, DM experiments, and GW interferometers.
The electroweak axion is identified with the fuzzy dark matter of a mass $m\simeq 10^{-20}$--$10^{-19}\,{\rm eV}$. The model predicts two components of dark matter, one is ultralight and the other is WIMP-like. The Chern-Simons-type interaction between the fuzzy dark matter and photon and the $B+L$ breaking proton decays are predicted.
If the dark sector contains 't Hooft-Polyakov monopoles and a small enough dark gauge coupling, dark monopoles could be a macroscopic dark matter candidate. Its Higgs-portal coupling to the Standard Model can modify the electroweak vacuum in the monopole interior. In the most striking cases, dark monopoles could even contain electroweak-symmetric cores and generate multi-hit signals at large-volume detectors. If they are produced via parametric resonance in the early Universe, monopoles with radii up to one micron and masses up to ten kilotonnes could account for all of dark matter.
A new weak-isospin triplet of scalar bosons is introduced to the Standard Model in order to ensure the electroweak symmetry for a conjectured new weak coupling between a hidden sector of the Universe, responsible for cold dark matter, and the Standard-Model sector (involving now the new triplet). The considered coupling may be called "electroweak portal" to the structure of hidden sector. After spontaneously breaking the electroweak symmetry by the Standard-Model Higgs mechanism, it includes the so called "photonic portal" introduced by us previously.
Adding an extra singlet scalar $S$ to the Higgs sector can provide a barrier at tree level between a false vacuum with restored electroweak symmetry and the true one. This has been demonstrated to readily give a strong phase transition as required for electroweak baryogenesis. We show that with the addition of a fermionic dark matter particle $χ$ coupling to $S$, a simple UV-complete model can realize successful electroweak baryogenesis. The dark matter gets a CP asymmetry that is transferred to the standard model through a $CP\ portal\ interaction$, which we take to be a coupling of $χ$ to $τ…
A weak photon interaction with the hidden sector of the Universe, introduced recently to realize a "photonic portal", (to such a hypothetic sector responsible for cold dark matter), is conjectured to be embedded in a more extended weak interaction displaying electroweak symmetry spontaneously broken by the Standard-Model Higgs mechanism. This is a hypothetic new weak interaction between hidden and Standard-Model sectors of the Universe, appearing in our model in addition to the conventional electroweak interaction acting in the Standard-Model sector.
In this comment we present an analysis of electroweak neutral triple gauge boson couplings projected out of the gauge sector of the extended non-commutative standard model. A brief overview of the current experimental situation is given.
These three lectures review the state of our understanding of electroweak interactions and the search for the agent of electroweak symmetry breaking. The themes of the lectures are (i) the electroweak theory and its experimental status, (ii) the standard-model Higgs boson, and (iii) aspects of electroweak theory beyond the standard SU(2)_L x U(1)_Y model.
Particle production at the end of a first-order electroweak phase transition may be rather generic in theories beyond the standard model. Dark matter may then be abundantly produced by this mechanism if it has a sizable coupling to the Higgs field. For an electroweak phase transition occuring at a temperature T_EW ~ 50-100 GeV, non-thermally generated dark matter with mass M_X > TeV will survive thermalization after the phase transition, and could then potentially account for the observed dark matter relic density in scenarios where a thermal dark matter component is either too small or absent…
The Higgs boson offers a unique window to hidden sector fields S_i, singlets under the Standard Model gauge group, via the renormalizable interactions |H|^2 S_i^2. We prove that such interactions can provide new patterns for electroweak breaking, including radiative breaking by dimensional transmutation consistent with LEP bounds, and trigger the strong enough first order phase transition required by electroweak baryogenesis.
In this review we discuss theories of the electroweak symmetry breaking sector in which the $W$ and $Z$ interactions become strong at an energy scale not larger than a few TeV.
We investigate an extension of the Standard Model (SM) with a U(1)' gauge symmetry, which is spontaneously broken by a complex scalar singlet and where the new gauge boson is a stable dark matter candidate via a Z2 flavor symmetry. The possibility of generating a strongly first order electroweak phase transition (EWPT) needed for the electroweak baryogenesis mechanism in this model is studied using a gauge independent method. Our result shows a considerable parameter space where both successful dark matter phenomenologies and a strongly first order EWPT can be achieved.
Energy-growing electroweak corrections in the Standard Model are potentially relevant for LHC physics, for Next generation of Linear Colliders (NLCs) and for ultrahigh energy cosmic rays. I present here the results of recent work in which electroweak evolution equations (the analogous of DGLAP equations in QCD) have been derived. The main features of these effects, mainly related to the fact that the electroweak sector is spontaneously broken, are pointed out.
We study a dynamical freeze-in production of the dark matter considering the electroweak phase transition history of the Universe. The kinematical thresholds of the decay and scattering processes for the dark matter production can be altered by the temperature dependent thermal masses of particles, which might lead to enhancement or reduction of the dark matter relic abundance. The second-stage strongly first-order electroweak phase transition (SFOEWPT) triggered by the hidden scalars can be probed at colliders and the gravitational wave detectors. The two-step SFOEWPT modified late decay FIMP…
In this Letter, we propose a new possible connection between dark matter relic density and baryon asymmetry of the universe. The portal between standard model sector and dark matter not only controls the relic density and detections of dark matter, but also allows the dark matter to trigger the first order electroweak phase transition. We discuss systematically possible scalar dark matter candidates, starting from a real singlet to arbitrary high representations. We show that the simplest realization is provided by a doublet, and that strong first-order electroweak phase transition implies a l…
The one-loop renormalizability of the electroweak sector of the Standard Model Extension with Lorentz violation is studied. Functional determinants are used to calculate the one-loop contributions of the higgs, gauge bosons and fermions to the one-loop effective action. The results are consistent with multiplicative renormalization of the SME coupling constants. Conventional Electroweak symmetry breaking is effectively unaltered relative to the standard case as the renormalized SME parameters are sufficient to absorb all infinite contributions.
We consider a hidden sector with new vectorlike confining gauge theories like QCD. Then a scale $Λ_H$ would be generated in the hidden sector by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. Then this scale $Λ_H$ can play a role of the SM Higgs mass parameter, triggering electroweak symmetry breaking (EWSB). Thus all the mass scales of the SM sector can arise from the hidden sector. Furthermore the lightest hadrons in the hidden sector is stable by the flavor conservation of the hidden sector strong interaction, and could be the cold dark matter (CDM). We…
We consider a minimal extension of the Standard Model which advocates a dark neutrino sector charged under a hidden $U(1)^\prime$. We show that neutrino masses can arise radiatively in this model. The observed values are compatible with a light dark sector below the electroweak scale and would imply new heavy fermions which may be testable in the next generation of beam dump searches at DUNE, NA62 and SHIP.
We analyse a simple extension of the SM with just an additional scalar singlet coupled to the Higgs boson. We discuss the possible probes for electroweak baryogenesis in this model including collider searches, gravitational wave and direct dark matter detection signals. We show that a large portion of the model parameter space exists where the observation of gravitational waves would allow detection while the indirect collider searches would not.
We study a model with an exotic new sector strongly coupled to the Higgs boson, in which supersymmetry is introduced to protect the quartic coupling from a large running and avoid potential vacuum stability problem. The fermionic components present vector like mass terms, through which the Higgs diphoton decay branching ratio can be tuned. The bosonic components trigger a strongly first order electroweak phase transition. We find a large parameter region of effective Yukawa coupling $y\gtrsim2$ and mass parameters $m_f\sim m_s$ of a few hundred GeV, that can simultaneously accommodate the diph…
We consider models with a vectorlike confining gauge theory in the hidden sector, and demonstrate that the origin of the electroweak symmetry breaking (EWSB) is due to the dimensional transmutation in the hidden sector gauge theory, and the lightest mesons in the hidden sector could be a good cold dark matter (CDM) candidate. There would be more than one neutral Higgs-like scalar bosons, and they could decay mainly into the CDM pair, if that decay channel is kinemtically allowed.
The framework of the electroweak chiral Lagrangian with a light Higgs is extended by an additional scalar and then generalized to N scalars in the Higgs sector. Divergences from scalar fluctuations are renormalized up to one loop using the background field method. The results are crosschecked against the case of one scalar. A subset of the divergences is demonstrated and crosschecked diagrammatically. Together with the complete one-loop renormalization of the electroweak chiral theory with one light Higgs conducted previously, this constitutes a renormalization framework of any pure scalar ext…
Adding radion perturbations (up to second order) to the static (RS) metric allows us to calculate the general first and second order interactions of the radion field with the electroweak vector bosons. We use these interactions to compute precision electroweak observables in the case of Higgs-radion mixing and compare with experiment.
A new representation of electroweak lepton sector is proposed. It consists of two Weyl spinors per one lepton family. It is shown that proposed representation is fully equivalent to the conventional left-handed iso-doublet. New type of plane wave solutions can be found under certain additional assumptions.
The phenomenology at future hadron colliders of a model with strong interacting vector and axial vector bosons possessing a discrete symmetry demanding mass degeneracy is presented.
In this work we have studied the phenomenological properties at future e+e- linear colliders of two models of strong electroweak symmetry breaking, characterized by the presence of new spin one strong interacting resonances.
Recent analyses have shown that the inclusion of electroweak corrections can alter significantly the energy spectra of Standard Model particles originated from dark matter annihilations. We investigate the important situation where the radiation of electroweak gauge bosons has a substantial influence: a Majorana dark matter particle annihilating into two light fermions. This process is in p-wave and hence suppressed by the small value of the relative velocity of the annihilating particles. The inclusion of electroweak radiation eludes this suppression and opens up a potentially sizeable s-wave…
In this paper we explore the interplay of scale dependence arising in the electroweak and the gravitational sector. Using the method of variational parameter setting leads naturally to spontaneous symmetry breaking and thus to electroweak gauge boson masses. We explore the phenomenological prospect of this model and the mapping to the program asymptotic safety.
A precise empirical relation between the electromagnetic coupling alpha(m_Z) and sin^2(theta^ell_{eff}) --where theta^ell_{eff} is the effective electroweak mixing angle extracted from Z leptonic decays-- is made manifest: alpha(m_Z) = sin^3(theta^ell_{eff})*cos(theta^\ell_{eff}}/(4π}.
By extending the scalar sector of the Standard Model (SM) by a U(1) singlet, we show that the electroweak symmetry breaking enables the formation of a stable, electrically neutral, colorless Q-ball which couples to the SM particle spectrum solely through the Higgs boson. This Q-ball has mainly weak and gravitational interactions, and behaves as a collection of weakly interacting massive particles. Therefore, it can be a candidate for the dark matter in the universe.
We analyze the validity of the theorems concerning the cancellation of the infrared and collinar divergences in the case of dark matter freeze-out in the early universe. In particular, we compute the electroweak logarithmic corrections of infrared origin to the annihilation cross section of a dark matter particle being the neutral component of a SU(2)_L multiplet. The inclusion of processes with final state W can modify significantly the cross sections computed with only virtual W exchange. Our results show that the inclusion of infrared logs is necessary for a precise computation of the dark …
We discuss the electroweak quintessence axion as a candidate for dark energy, taking into account observational as well as quantum-gravity constraints.
We study the process $e^+ e^- \to γγν\barν$ in the context of a strong electroweak symmetry breaking model, which can be a source of events with two photons and missing energy at LEP2. We investigate bounds on the model assuming that no deviation is observed from the Standard Model within a given experimental error.
We consider a hidden sector with a vectorlike confining gauge theory like QCD with $N_{h,c}$ colors and $N_{h,f}$ light quarks ${\cal Q}_h$ in the hidden sector. Then a scale $Λ_H$ would be generated by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. This scale $Λ_H$ can play a role of the SM Higgs mass parameter, triggering electroweak symmetry breaking (EWSB). Furthermore the lightest mesons in the hidden sector is stable by flavor conservation of the hidden sector strong interaction, and could be a good cold dark matter (CDM). We study collider phenomeno…
We discuss a novel approach to renormalize the Electroweak Sector of the Standard Model, in which \sin^2θ_{eff}, measured at the Z^0 peak, is identified with the basic renormalized electroweak mixing parameter. This approach shares the desirable convergence properties of the MS scheme and provides a framework for calculations that are strictly independent of the electroweak scale in finite orders of perturbation theory. We illustrate the method with updated precise calculations of \sin^2θ_{eff} and M_W, as functions of M_H, and comment on the implications of these calculations for the Higgs bo…
An effective lagrangian describing a strong interacting electroweak sector is considered. It contains new vector and axial-vector resonances all degenerate in mass and mixed with $W$ and $Z$. The model, for large mass of these degenerate gauge bosons, becomes identical to the standard model in the classical limit of infinite Higgs mass. The limits on the parameter space of this model from future $e^+e^-$ colliders are presented.
In this article we review the electroweak charged and neutral currents in the Non-Commutative Standard Model (NCSM) and compute the Higgs and Yukawa parts of the NCSM action. With the aim to make the NCSM accessible to phenomenological considerations, all relevant expressions are given in terms of physical fields and Feynman rules are provided.
If there are no light Higgs bosons found below $\cal O$(800 GeV) or so, the interactions among longitudinally-polarized vector bosons ($\wl$) will become strong at the TeV region, and new physics that is responsible for the electroweak symmetry breaking must emerge at this energy scale. We discuss the phenomenological prospects of the Strongly-interacting Electro-Weak Sector (SEWS) at future TeV linear colliders and hadronic supercolliders.
The object of this thesis is the study of some open problems in the electroweak matter sector from an effective theory perspective. The topics studied include: General aspects of dynamical symmetry breaking models, studying what traces these mechanisms may leave at low energies. A treatment of CP violation and family mixing in the framework of an effective theory and the determination of some of the effective couplings involved. Theoretical issues connecting the renormalization group, gauge invariance, CP, CPT and physical observables. The possibility of experimentally constraining some of the…
We consider the possibility of observing a parity violating but $CP$ conserving interaction in the symmetry breaking sector of the electroweak theory. We find that the best probe for such an interaction is a forward-backward asymmetry in $W^+W^-$ production from polarized $e^-_R e^+_L$ collisions. An observable asymmetry would be strong evidence against a custodial $SU(2)$ symmetry. We also discuss the effects of such an interaction in future $e^- γ$ colliders as well as in rare decays of $K$ and $B$ mesons.
Well-motivated electroweak dark matter is often hosted by an extended electroweak sector which also contains new lepton pairs with masses near the weak scale. In this paper, we explore such electroweak dark matter via combining dark matter direct detections and high-luminosity LHC probes of new lepton pairs. Using $Z$- and $W$-associated electroweak processes with two or three lepton final states, we show that dependent on the overall coupling constant, dark matter mass up to $170-210$ GeV can be excluded at $2σ$ level and up to $175-205$ GeV can be discovered at $5σ$ level at the 14 TeV LHC w…
In these proceedings we present the latest developments in our effort to include vector boson scattering (VBS) measurements into global SMEFT fits of LHC data. We present some updates to our initial study of arXiv:2101.03180 as well as comment on a possible road map for the inclusion of higher orders beyond dimension 6 in the SMEFT and on the interpretation of VBS data in other EFT frameworks.
Higgs sector extensions beyond the Standard Model (BSM) provide additional sources of CP violation and further scalar states that help to trigger a strong first order electroweak phase transition (SFOEWPT) required to generate the observed baryon asymmetry of the Universe through electroweak baryogenesis. We investigate the CP-violating 2-Higgs-Doublet Model (C2HDM) and the Next-to-Minimal 2-Higgs-Doublet Model (N2HDM) with respect to their potential to generate an SFOEWPT while being compatible with all relevant and recent theoretical and experimental constraints. The implications of an SFOEW…
We present a unified analysis of the two main production processes of vector boson pairs at the LHC, VV-fusion and qqbar annihilation, in a minimal strongly interacting electroweak symmetry breaking sector. Using a unitarized electroweak chiral Lagrangian formalism and modeling the final V_L V_L strong rescattering effects by a form factor, we describe qqbar annihilation processes in terms of the two chiral parameters that govern elastic V_L V_L scattering. Depending on the values of these two chiral parameters, the unitarized amplitudes may present resonant enhancements in different angular m…
We propose a scenario that the Electroweak-Skyrmion, a solitonic object made of the Higgs field and the electroweak gauge fields, is identified as an asymmetric dark matter. In this scenario, the relic abundance of the dark matter is related to the baryon asymmetry of the Universe through a sphaleron-like process. We show that the observed ratio of dark matter abundance to the baryon asymmetry can be explained by this scenario with an appropriate choice of model parameters that is allowed by currently available experimental constraints.
The interaction of QCD and electroweak sector with gravity is characterized by the generation of a massless pole in a specific form factor present in the 1-loop effective action. We briefly illustrate how to single out this behaviour in perturbation theory, by taking as an example the $TJJ$ vertex, with $T$ denoting the energy momentum tensor of the Standard Model. The breaking of scale invariance, due to the trace anomaly, is then related to the appearance of a local degree of freedom in the effective action, which is of dilaton type.
We discuss the prospects for detecting at a muon collider the massive new vector resonances V and light pseudo-Nambu-Goldstone bosons P of a typical strongly interacting electroweak sector (as represented by the BESS model). Expected sensitivities to V's at a high energy collider are evaluated and the excellent prospects for discovering P's via scanning at a low energy collider are delineated.
We discuss spectra of gravitational waves which are originated by the strongly first order phase transition at the electroweak symmetry breaking, which is required for a successful scenario of electroweak baryogenesis. Such spectra are numerically evaluated without high temperature expansion in a set of extended scalar sectors with additional N isospin-singlet fields as a concrete example of renormalizable theories. We find that the produced gravitational waves can be significant, so that they are detectable at future gravitational wave interferometers such as DECIGO and BBO. Furthermore, sinc…
We study the possible experimental signatures resulting from a strongly-interacting electroweak sector at $e^-e^-$ colliders, emphasizing the signal enhancement by high beam polarization. We also discuss the unique role for operating the collider in $e^-γ$ mode to produce a heavy isosinglet vector state $ω_T$.
We study the expected phenomenology at present (Tevatron) and future (Tevatron Upgrade, LHC) hadronic colliders of a model describing a strong electroweak symmetry breaking sector with both vector and axial vector strong interacting bosons degenerate in mass. Due to decoupling, this model at low energies is almost indistinguishable from the Standard Model, passing therefore all low energy precision tests at LEPI. We will show that it gives quite visible signals at forthcoming hadronic accelerators. The new charged vector bosons can be detected more easily than the neutral ones.
We overview the structure of the effective action involving a dilaton and a Higgs in the Standard Model, which has been computed recently for the neutral currents sector. We discuss the role of the dilatation current ($J_D$) and of an effective degree of freedom appearing in the $J_D V V'$ correlator, with $V$ any neutral current, which can be interpreted as a Nambu-Goldstone mode generated by the anomalous breaking of the dilatation symmetry.
The effects of the electroweak symmetry breaking sector in rare $B$ and $K$ decays are considered in the presence of new strong dynamics at a large energy scale. In the context of the low energy effective lagrangian of the symmetry breaking sector, we focus on the contributions that are not constrained by bounds on oblique corrections or anomalous triple gauge boson vertices. We find that these have very little effect in $b\to sγ$, but potentially large contributions appear in $b\to s\ell^+\ell^-$ and $b\to sν\barν$ as well as in $b\to s g$ processes. Deviations from the standard model in rare…
The study of the scattering at high energy of the gauge bosons W and Z, in particular longitudinally polarized W and Z, can clarify the mechanism of spontaneous symmetry breaking in the Standard Model of the electroweak interactions. Different models of strong electroweak sector, based on the effective lagrangian approach are briefly reviewed. They include models with no resonance, with scalar resonance, additional vector and axial-vector resonances. The effective Lagrangians are derived from the chiral symmetry of the symmetry breaking sector. Limits on these models from existing measurements…
We consider pair-production of electroweakinos promptly decaying to light gravitinos in general gauge mediation scenarios within the minimal supersymmetric standard model. Typically the presence of photons and missing transverse momentum is the key signature for this kind of scenarios. We highlight where LHC analyses which have originally been designed to probe different scenarios provide complementary constraints with respect to the dedicated searches and we present the constraints on the parameter space.
