We discuss the possibility to indirectly test First Order Phase Transitions of hidden sectors. We study the interesting example of a {\it dark standard model} with a deformed parameter space in the Higgs potential. A dark electroweak phase transition can be limited from next future experiments like eLISA and DECIGO.
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.
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.
We discuss topological transitions during parametric resonance in the gauge sector of electroweak theory. It is shown that the resonance leads to separation of topological indices of the gauge and Higgs fields, resulting in topological transitions of non-sphaleron nature.
We consider the phenomenological consequences of a hidden Higgs sector extending the Standard Model (SM), in which the matter content are uncharged under the SM gauge groups. We consider a simple case where the hidden sector is gauged under a U(1) with one Higgs singlet. The only couplings between SM and the hidden sector are through mixings between the neutral gauge bosons of the two respective sectors, and between the Higgs bosons. We find signals testable at the LHC that can reveal the existence and shed light on the nature of such a hidden sector.
It is shown that in general the gauge given by the limit of $ξ\to 0$ in $R_ξ$ gauge does not necessarily agree with the unitary gauge by examining the symmetry breaking of two steps from ${\rm SU(3) \otimes U(1)}_N$ to ${\rm SU(2) \otimes U(1)}_Y$ and then to ${\rm U(1)}_{em}$.
An extra Abelian gauge symmetry is motivated in many new physics models in both supersymmetric and nonsupersymmetric cases. Such a new gauge symmetry may interact with both the observable sector and the hidden sector. We systematically investigate the most general residual discrete symmetries in both sectors from a common Abelian gauge symmetry. Those discrete symmetries can ensure the stability of the proton and the dark matter candidate. A hidden sector dark matter candidate (lightest U-parity particle or LUP) interacts with the standard model fields through the gauge boson Z', which may sel…
We summarize the results of the New Gauge Boson Subgroup on the physics of extended gauge sectors at future colliders as presented at the 1996 Snowmass workshop. We discuss the direct and indirect search reaches for new gauge bosons at both hadron and lepton colliders as well as the ability of such machines to extract detailed information on the couplings of these particles to the fermions and gauge bosons of the Standard Model. [To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics-Snowmass96, Snowmass, CO, 25 June-12 July, 1996.]
Signatures of extended gauge models at high energy \epem\ linear colliders are summarized. Talk presented at the Workshop on Physics and Experiments with Linear \epem\ Colliders, Waikoloa, Hawaii, April 1993.
We give a brief overview of searches at TeV e^+e^- colliders for new particles that arise in models with extended gauge sectors. We concentrate on some recent developments in $W'$ searches and on leptoquark searches. We also briefly mention $Z'$ searches.
Intersecting D-brane theories motivate the existence of exotic U(1) gauge bosons that only interact with the Standard Model through kinetic mixing with hypercharge. We analyze an effective field theory description of this effect and describe the implications of these exotic gauge bosons on precision electroweak, LHC and ILC observables.
We deal with extensions of the Standard Model by adding horizontal interactions between particle generations. We calculate two loop corrections caused by the presence of coupling between hypothetical horizontal gauge bosons and matter fields, both at low and high energy. It is proved numerically, that the coupling of such extra bosons does not affect the positive features of unified and extended standard models with horizontal symmetry discussed in former publications.
We discuss gauge mediation in the case where the hidden sector is strongly coupled but, via the gauge-gravity correspondence, admits a weakly-coupled description in terms of a warped higher-dimensional spacetime. In this framework, known as holographic gauge mediation, the visible-sector gauge group is realized in the gravitational description by probe D-branes and the non-supersymmetric state by normalizable perturbations to the geometry. Using the formalism of general gauge mediation, supersymmetry-breaking soft terms in the visible sector can be related to the two-point functions of the hid…
Assuming high temperature and taking subleading temperature dependence into account, gauge dependence of one-loop electron dispersion relation is investigated in massless QED at zero chemical potential. The analysis is carried out using a general linear covariant gauge. The equation governing the gauge dependence of the dispersion relation is obtained and used to prove that the dispersion relation is gauge independent in the limiting case of momenta much larger than $eT$. It is also shown that the effective mass is not influenced by the leading temperature dependence of the gauge dependent par…
The sequestering of supersymmetry (SUSY) breaking parameters, which is induced by superconformal hidden sector, is one of the solutions for the mu/B_mu problem in gauge-mediated SUSY-breaking scenario. However, it is found that the minimal messenger model does not derive the correct electroweak symmetry breaking. In this paper we present a model which has the coupling of the messengers with the SO(10) GUT-symmetry breaking Higgs fields. The model is one of the realistic extensions of the gauge mediation model with superconformal hidden sector. It is shown that the extension is applicable for a…
We propose a new class of gauge mediated supersymmetry breaking models where the standard model gauge group is embedded into the gauge group $SU(2)_L\times U(1)_{I_{3R}}\times U(1)_{B-L}$ [or $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$] at the supersymmetry breaking scale $Λ_S$. The messenger sector in these models can consist of color singlet but $U(1)_{I_{3R}}$ and $U(1)_{B-L}$ nonsinglet fields. The distinguishing feature of these models are (i)exact R-parity conservation, (ii) nonvanishing neutrino masses and (iii) a unified hidden and messenger sector potential. The simplest version of these…
We address the question, how general is the gauge sector in extra-dimensional models which explain hierarchies of masses and mixings of quarks, charged leptons and neutrinos in terms of a single family of multidimensional fermions. We give qualitative arguments that though there are a plethora of possible variations, they do not result in drastical changes of phenomenology.
We propose a dynamical scenario beyond the standard model, in which the radiative correction to the Higgs mass parameter is suppressed due to a large anomalous dimension induced through a conformal invariant coupling with an extra gauge sector. Then the anomalous dimension also suppresses the Yukawa couplings of the Higgs field. However, the large top Yukawa coupling can be generated effectively through mixing among top quarks and the fermions of the conformal gauge sector. This scenario is found to predict a fairly heavy Higgs mass of about 500 GeV. We present an explicit model and show consi…
We study the constraints on the new parameters in the gauge sector of gauged two Higgs doublet model using the electroweak precision test data collected from the Large Electron Positron Collider (LEP) at and off the Z-pole as well as the current Drell-Yan and high-mass dilepton resonance data from the Large Hadron Collider (LHC). Impacts on the new parameters by the projected sensitivities of various electroweak observables at the Circular Electron Positron Collider (CEPC) proposed to be built in China are also discussed. We also clarify why the Stüeckelberg mass $M_Y$ for the hypercharge $U(1…
New fundamental particles, charged under new gauge groups and only weakly coupled to the standard sector, could exist at fairly low energy scales. In this article we study a selection of such models, where the secluded group either contains a softly broken U(1) or an unbroken SU(N). In the Abelian case new γv gauge bosons can be radiated off and decay back into visible particles. In the non-Abelian case there will not only be a cascade in the hidden sector, but also hadronization into new πv and ρv mesons that can decay back. This framework is developed to be applicable both for e+e- and pp co…
We study the static gluon and quark propagator of the Hamiltonian approach to Quantum Chromodynamics in Coulomb gauge in one-loop Rayleigh--Schrödinger perturbation theory. We show that the results agree with the equal-time limit of the four-dimensional propagators evaluated in the functional integral (Lagrangian) approach.
We consider a generic abelian hidden sector that couples to the Standard Model only through gauge-invariant renormalizable operators. This allows the exotic Higgs boson to mix with the Standard Model Higgs boson, and the exotic abelian gauge boson to mix with the Standard Model hypercharge gauge boson. One immediate consequence of spontaneous breaking of the hidden sector gauge group is the possible decay of the lightest Higgs boson into four fermions through intermediate exotic gauge bosons. We study the implications of this decay for Higgs boson phenomenology at the Fermilab Tevatron Collide…
We discuss the structure of the neutrino mass matrix as derived from a nonuniversal electroweak gauge interaction model. We discuss two interesting patterns of neutrino masses. The first pattern is hierarchal which fits the LMA or LOW solutions of solar neutrino data. The second pattern gives rise to inverted mass spectrum which fits the currently not preferred SMA solution. The mechanism for generating a light sterile neutrino mass is interesting and is briefly discussed.
Present and future prospects for the discovery of new gauge bosons, $Z'$ and $W'$, are reviewed. Particular attention is paid to hadron and $e^+e^-$ collider searches for the $W'$ of the Left-Right Symmetric Model. (Presented at the {\it Fourth International Conference on Physics Beyond the Standard Model}, Lake Tahoe, CA, December 13-18, 1994.)
We add fermions to an abelian-gauged hidden sector. We show that the lightest can be the dark matter with the right thermal relic abundance, and discovery is within reach of upcoming dark matter detectors. We also show that these fermions change Higgs boson phenomenology at the Large Hadron Collider (LHC), and in particular could induce a large invisible width to the lightest Higgs boson state. Such an invisibly decaying Higgs boson can be discovered with good significance in the vector boson fusion channel at the LHC.
We consider a generic renormalizable and gauge invariant messenger sector and derive the sparticle mass spectrum using the formalism introduced for General Gauge Mediation. Our results recover many expressions found in the literature in various limits. Constraining the messenger sector with a global symmetry under which the spurion field is charged, we analyze Extraordinary Gauge Mediation beyond the small SUSY breaking limit. Finally, we include D-term contributions and compute their corrections to the soft masses. This leads to a perturbative framework allowing to explore models capable of f…
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}.
The scalar sector of the linear formulation of the degenerate BESS model is analyzed. The model predicts two additional scalar states which mix with the SM Higgs. As a consequence the properties of the SM Higgs are modified and Higgs precision measurements can constrain the mixing angle. One of the two additional Higgses has no coupling to fermions and suppressed couplings to ordinary gauge bosons, therefore its detection is difficult. The production of the other two Higgses at future e+e- linear colliders in the Higgstrahlung and fusion channels is investigated.
We study the pure-gauge sector of an $SU(N)$ gauge theory, equivariantly gauge fixed to $SU(N-1)\times U(1)$, which is an asymptotically free non-linear sigma model in four dimensions. We show that dimensional transmutation takes place in the large-$N$ limit, and elaborate on the relevance of this result for a speculative scenario in which the strong longitudinal dynamics gives rise to a novel Higgs-Coulomb phase.
Probing a minimal dark gauge sector via microlensing of compact dark objects
Universidad de Guanajuato(瓜纳华托大学);Universidad Michoacana de San Nicolás de Hidalgo(米却肯圣尼古拉斯自治大学);University of Science and Technology of China(中国科学技术大学);Universidad Nacional Autónoma de México(墨西哥国立自治大学);Universitat de València(瓦伦西亚大学)
There are many applications in gauge theories where the usually employed framework involving gauge-dependent Green's functions leads to considerable problems. In order to overcome the difficulties invariably tied to gauge dependence, we present a manifestly gauge-invariant approach. We propose a generating functional of appropriately chosen gauge-invariant Green's functions for the bosonic sector of the standard model. Since the corresponding external sources emit one-particle states, these functions yield the same S-matrix elements as those obtained in the usual framework. We evaluate the gen…
In supersymmetric grand unified theories, the gauge hierarchy achieved by a fine-tuning in the superpotential can be violated in the presence of soft breaking terms. We examine this problem in Einstein supergravity with hidden-sector supersymmetry breaking. We show that the hierarchy is preserved if couplings of the hidden sector to visible-sector fields in the superpotential satisfy a certain requirement.
We introduce fully SGUTs, SUSY grand unified theories that, upon symmetry breaking through the Higgs mechanism, decompose into a visible sector and an extra sector where the dynamics of the extra sector gauge group is responsible for SUSY breaking. Fully SGUTs thus have the important feature that all gauge groups of the visible sector and the extra sector unify into a simple gauge group at the SGUT scale, therefore generalizing the successful MSSM gauge coupling unification to all the gauge couplings of the theory. By focusing on the ISS SUSY-breaking mechanism in the extra sector, we show tha…
We discuss the implications of a gauged Abelian hidden-sector communicating with the Standard Model (SM) fields via kinetic mixing with the SM hypercharge gauge field, or via the Higgs quartic interaction. We discuss signatures of the hidden-sector gauge boson at the LHC in the four-lepton channel. We show that a hidden-sector fermion can be a natural dark-matter candidate with the correct relic-density, discuss direct-detection prospects, and show how Higgs signatures may be altered at the LHC.
We study the hidden sector effects to the mass renormalization of a simplest gauge-mediated supersymmetry breaking scenario. We point out that possible hidden sector contributions render the soft scalar masses smaller, resulting in drastically different sparticle mass spectrum at low energy. In particular, in the ${\bf 5}+\bar{\bf 5}$ minimal gauge mediated supersymmetry breaking with high messenger scale (that is favored by the gravitino cold dark matter scenario), we show that stau can be the next lightest superparticle for moderate values of hidden sector self coupling. This provides a very…
The lighter neutral scalar Higgs mass is examined in gauge-mediated supersymmetry-breaking models in which the messenger sector responsible for SUSY breaking is allowed to involve more general sets of $SU(3) \otimes SU(2) \otimes U(1)$ multiplets than those contained in the SU(5) $5 + \bar{5}$ or $10 + \bar{10}$ multiplets. The largest mass for the lighter scalar Higgs is found to be 132 GeV when the breaking parameter $Λ$ is taken to be 100 TeV\@. Thus the predictions for the lightest Higgs mass can be tested at the upgraded Tevatron runs for these general classes of GMSB models.
The ability of high energy $e^+e^-$ colliders to indirectly probe the existence of heavy new charged gauge bosons via their exchange in the reaction $e^+e^-\to ν\barνγ$ is investigated. It is shown that examination of the resulting photon energy spectrum with polarized beams can extend the $W'$ search reach above the center of mass energy. [ To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics - Snowmass96, Snowmass, CO, 25 June - 12 July 1996.]
The Hidden Abelian Higgs Model (HAHM) is an extension of the Standard Model based on the gauge group $G =SU(3)_{C} \times SU(2)_{L} \times U(1)_{Y} \times U(1)_{X}$ i.e. an extra $U(1)_{X}$ gauge group in addition to the SM gauge groups.In HAHM, an Abelian Hidden sector is coupled to the SM, and the resulting new Higgs boson H and new neutral gauge boson $Z_{HAHM}$ fields are allowed to mix with the corresponding SM fields. In this work, we search for the new neutral gauge boson $Z_{HAHM}$ and new Higgs boson in the context of the Hidden Abelian Higgs Model (HAHM) through the decay process $pp…
We derive new bounds on hidden sector gauge bosons which could produce new energy loss mechanisms in supernovae, enlarging the excluded region in mass-coupling space by a significant factor compared to earlier estimates. Both considerations of trapping and possible decay of these particles need to be incorporated when determining such bounds, as does scattering on both neutrons and protons. For masses and couplings near the region which saturates current bounds, a significant background of such gauge bosons may also be produced due to the cumulative effects of all supernovae over cosmic histor…
The messenger sector of existing models of gauge-mediated supersymmetry breaking may be simplified by using a non-renormalizable superpotential term to couple the vector-like quark and lepton messenger fields to a chiral gauge-invariant of the supersymmetry-breaking sector. This eliminates the need for a fundamental singlet and for an additional gauge sector needed to generate appropriate expectation values for the singlet component fields. This scenario is more natural if the supersymmetry-breaking sector itself involves a non-renormalizable superpotential. Several examples are constructed ba…
We propose a dark matter model in which the dark sector is gauged under a new SU(2) group. The dark sector consists of SU(2) dark gauge fields, two triplet dark Higgs fields, and two dark fermion doublets (dark matter candidates in this model). The dark sector interacts with the SM sector through kinetic and mass mixing operators. The model explains both PAMELA and Fermi LAT data very well and also satisfies constraints from both the DM relic density and Standard Model precision observables. The phenomenology of the model at the LHC is also explored.
In this work we propose the Z -> gamma gamma decay as a process strictly forbidden in the standard model, suitable for the search of noncommutativity of coordinates at very short distances. We computed the Z -> gamma gamma partial width in the framework of the recently proposed one-loop renormalizable gauge sector of the noncommutative standard model. New experimental possibilities at LHC are analyzed and a firm bound to the scale of noncommutativity parameter is set around 1 TeV.
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.
We explore the dark matter freeze-in mechanism within the gauge mediation framework, which involves a hidden Feebly Interacting Massive Particle (FIMP) coupling feebly with the messenger fields while the messengers are still in the thermal bath. The FIMP is the fermionic component of the pseudo-moduli in a generic metastable supersymmetry (SUSY) breaking model and resides in the hidden sector. The relic abundance and the mass of the FIMP are determined by the SUSY breaking scale and the feeble coupling. The gravitino, which is the canonical dark matter candidate in the gauge mediation framewor…
We propose the Z -> gamma gamma decay, a process strictly forbidden in the standard model, as a signal suitable for the search of noncommutativity of coordinates at very short distances. We compute the Z -> gamma gamma partial widthin the framework of the recently proposed renormalizable gauge sector of the noncommutative standard model. The one-loop renormalizability is obtained for the model containing the usual six representations of matter fields of the first generation. Even more, the noncommutative part is finite or free of divergences, showing that perhaps new interaction symmetry exist…
Due to the nonperturbative masslessness of the ghost field, ghost loops that contribute to gluon Green's functions in the Landau gauge display infrared divergences, akin to those one would encounter in a conventional perturbative treatment. This is in sharp contrast with gluon loops, in which the perturbative divergences are tamed by the dynamical generation of a gluon mass acting as an effective infrared cutoff. In this paper, after reviewing the full nonperturbative origin of this divergence in the two-gluon sector, we discuss its implications for the three- and four-gluon sector, showing in…
We consider the idea of combining the supersymmetry breaking and messenger sectors in models of gauge-mediated supersymmetry breaking. We discuss the advantages and problems of such models, and present an existence proof by constructing an explicit example. We explore in some detail the low-energy supersymmetry-breaking dynamics and the generation of supersymmetry-breaking soft masses of the standard model superpartners, and discuss many features which are likely to be shared by more realistic models with dynamical messengers.
The gauge coupling unification can be achieved at a unification scale around 5 x 10^{13} GeV if the Standard Model scalar sector is extended with extra Higgs-like doublets. The relevant new scalar degrees of freedom in the form of chiral Z* and W* vector bosons might "be visible" already at about 700 GeV. Their eventual preferred coupling to the heavy quarks explains the non observation of these bosons in the first LHC run and provides promising expectation for the second LHC run.
We propose a general scheme for constructing models in which the Standard Model (SM) gauge interactions are the mediators of supersymmetry breaking to the fields in the supersymmetric SM, but where the SM gauge groups couple directly to the sector which breaks supersymmetry dynamically. Despite the direct coupling, the models preserve perturbative unification of the SM gauge coupling constants. Furthermore, the supergravity contributions to the squark and slepton masses can be naturally small, typically being much less than 1% of the gauge mediated contributions. Both of these goals can be ach…
We consider gauge-mediated models of supersymmetry (SUSY) breaking with strongly coupled nonabelian messenger gauge theory. After integrating out the SUSY-breaking and messenger sectors, we directly see that the effective Kahler potential transmits the SUSY breaking to the standard model sector.
This paper discusses electroweak collider signatures of the NMSSM with multiple-sector gauge mediation. We focus on the production of neutralinos and charginos which cascade decay into standard model particles and lighter supersymmetric particles, with special emphasis on final states with multiple photons. A search strategy for signatures with at least three photons is presented and compared with current exclusion limits based on two-photon searches. We show that in many regions of the parameter space our strategy gives stronger constraints than the existing two-photon analysis for these mode…
We discuss mechanisms for naturally generating GeV-scale hidden sectors in the context of weak-scale supersymmetry. Such low mass scales can arise when hidden sectors are more weakly coupled to supersymmetry breaking than the visible sector, as happens when supersymmetry breaking is communicated to the visible sector by gauge interactions under which the hidden sector is uncharged, or if the hidden sector is sequestered from gravity-mediated supersymmetry breaking. We study these mechanisms in detail in the context of gauge and gaugino mediation, and present specific models of Abelian GeV-scal…
We discuss the connection between the vacuum energy problem and the number of dark matter sectors and its relation to the cancellation of quadratic divergences both in the cosmological constant and simultaneously in the polarization tensor renormalizing the Higgs meson mass. In the absence of global supersymmetry, the cancellations of quartic and quadratic divergences call for a dark Higgs scalar sector. We estimate the number of hidden(dark) gauged Higgs field sectors to be equal to five. The masses of dark bosons may be of the order of the Standard Model boson masses. Then the following pict…
We present a study of the trilinear gauge interactions in extensions of the Standard Model (SM) with several anomalous extra U(1)'s, identified in various constructions, from special vacua of string theory to large extra dimensions. In these models an axion and generalized Chern-Simons interactions for anomalies cancelation are present. We derive generalized Ward identities for these vertices and discuss their structure in the Stuckelberg and Higgs-Stuckelberg phases. We give their explicit expressions in all the relevant cases, which can be used for phenomenological studies of these models at…
Electroweak observables are highly sensitive to the loop corrections. Therefore, a proper gauge-fixing mechanism is always needed to define the propagators which are involved in Feynman loop amplitude. With this spirit we compute gauge-fixing mechanism in five dimensional (5-D) Universal Extra-Dimensional (UED) model with boundary localised terms (BLTs). These BLTs are not 5-D operators in four-dimensional (4-D) effective theory but some sort of boundary conditions on the respective fields at the fixed points of $S^1/Z_2$ orbifold. Furthermore, these BLTs non-trivially modify the Kaluza-Klein …
We propose a framework in which visible matter interacts with matter from a hidden sector through mass mixings of Stückelberg U(1) gauge fields. In contrast to other Z' mediation scenarios, our setup has the added appealing features that (i) the choice of Z's can be significantly broadened without necessarily introducing unwanted exotic matter and (ii) there can be sizable tree-level interactions between the visible and hidden sectors. String theory embeddings of this scenario and their phenomenological features are briefly discussed.
We give an extensive description of the renormalisation of the Higgs sector of the minimal supersymmetric model in SloopS. SloopS is an automatised code for the computation of one-loop processes in the MSSM. In this paper, the first in a series, we study in detail the non gauge invariance of some definitions of tan(beta). We rely on a general non-linear gauge fixing constraint to make the gauge parameter dependence of different schemes for tan(beta) at one-loop explicit. In so doing, we update, within these general gauges, an important Ward-Slavnov-Taylor identity on the mixing between the pse…
In secluded dark sector scenario, the connection between the visible and the dark sector can be established through a portal coupling and its presence opens up the possibility of non-adiabatic evolution of the dark sector. To study the non-adiabatic evolution of the dark sector, we have considered a $U(1)_{L_μ- L_τ} \otimes U(1)_X$ extension of the standard model (SM). Here the dark sector is charged only under $U(1)_X$ gauge symmetry whereas the SM fields are singlet under this symmetry. Due to the presence of tree-level kinetic mixing between $U(1)_X$ and $U(1)_{L_μ- L_τ}$ gauge bosons, the …