The thermodynamical properties of a neutral vector boson gas in a constant magnetic field are studied starting from the spectrum given by Proca formalism. Bose Einstein Condensation (BEC) and magnetization are obtained, for the three and one dimensional cases, in the limit of low temperatures. In three dimensions the gas undergoes a phase transition to an usual BEC in which the critical temperature depends on the magnetic field. In one dimension a diffuse condensate appears as for the charged vector boson gas. In both cases, the condensation is reached not only by decreasing the temperature but also by increasing the magnetic field. In three and one dimensions self-magnetization is possible. The anisotropy in the pressures due to axial symmetry imposed to the system by the magnetic field is also discussed. The astrophysical implications are commented.
We study the interference of resonant Higgs boson exchange in neutralino production in μ^+ μ^- annihilation with longitudinally polarized beams. We use the energy distribution of the decay lepton in the process \neutralino_j \to \ell^\pm \slepton^\mp to determine the polarization of the neutralinos. In the CP conserving Minimal Supersymmetric Standard Model a non-vanishing asymmetry in the lepton energy spectrum is caused by the interference of Higgs boson exchange channels with different CP eigenvalues. The contribution of this interference is large if the heavy neutral bosons H and A are nea…
Extra neutral gauge bosons and Higgs bosons in an effective low-energy $SU(2)_L \times SU(2)_I \times U(1)_Y \times U(1)_{Y^{\prime}}$ model, which is a subgroup of $E_6$, are studied. $SU(2)_I$ is a subgroup of $SU(3)_R$ and commutes with the electric charge operator, so the three corresponding gauge bosons are neutral. Electroweak precision experiments are used to put constraints on masses of the extra neutral gauge bosons and on the mixings between them and the ordinary Z boson, including constraints arising from a proposed measurment of the weak charge of the proton at Jefferson Lab. Bound…
We study the equation of motion of neutral vector bosons bearing a magnetic moment (MM). The effective rest mass of vector bosons is a decreasing function of the magnetic field intensity. Consequently a diffuse condensation of the bosons appears below a critical value of the field. For typical values of densities and magnetic fields the magnetization is positive and the neutral boson system can maintain a magnetic field self-consistently. A discussion of the relevance in astrophysics is presented.
The SU(3)$_L\otimesU(1)_N$ electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of neutral SU(3)$_L\otimesU(1)_N$ Higgs bosons in the $e^-e^+$ Next Linear Collider (NLC) and in the CERN Linear Collider (CLIC). We compute the branching ratios of two of the SU(3)$_L\otimesU(1)_N$ neutral Higgs bosons and study the possibility to detect them and the $Z^\prime$ extra neutral boson of the model.
In the current work, We investigated the production of neutral Higgs boson and two charged Charginos owing to electron-positron annihilation via different propagators
We study the neutral Higgs boson production at the $e^- e^+$ linear collider in the two Higgs doublet model with the CP violation. The CP-even and CP-odd scalars are mixed in this model, which affects the production process of neutral Higgs boson.
We construct a new color neutral ground state of two-flavor color superconducting quark matter. It is shown that, in contrast with the conventionally considered ground state with diquark pairing in only one color direction, this new state is stable against arbitrary diquark fluctuations. In addition, the thermodynamical potential is found to be lower for this new state than for the conventional one.
The relevance of existing $νN$ deep inelastic scattering data to models containing a leptophobic neutral vector boson is discussed. It is shown that this neutral current data is in good agreement with the Standard Model and disfavors such a leptophobic boson.
The Georgi-Machacek model predicts the existence of four neutral Higgs bosons, one of which can be identified as the 125-GeV Higgs boson. The latest Higgs data favor the parameter space of small mixing angle alpha between the two custodial singlets of the model. The other two neutral Higgs bosons belong respectively to the custodial triplet and quintet. We study the general decay and production properties of these particles in the small-alpha scenario. Constraints on the SU(2)_L triplet vacuum expectation value are obtained as a function of the exotic Higgs boson masses using latest ATLAS data…
We show that the Higgs boson exchange contribution can be large in three-body decays of neutralinos even in the case of small tan(beta). This enlarges the branching ratios for the decays neutralino_2 -> neutralino_1 b \bar{b} and neutralino_2 -> neutralino_1 tau- tau+. This is the case in the region of the parameter space where the two lightest neutralinos are gaugino-like, the sfermions are heavier than 300 GeV, and m_A0 = 200 GeV or smaller.
We present the one-loop corrected decay widths of a neutral (charged) Higgs boson into a chargino or neutralino pair (chargino and neutralino) in the CP-conserving MSSM. The chargino and neutralino parameters are renormalized in the on-shell scheme and it is shown that the correction due to the chargino/neutralino mass matrix renormalization is comparable to the conventional vertex correction. The full corrections are typically of the order of 10%.
We investigate the differential branching ratio, branching ratio, differential forward-backward asymmetry, the forward-backward asymmetry of the lepton pair and the lepton polarization asymmetry of the exclusive $B\to τ^+ τ^- γ$ decay in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependencies of these quantities on the model parameters and also on the neutral Higgs boson effects. We found that they get considerable enhancement from the two Higgs doublet model compared to the standard model and neutral Higgs boson effects are quite sizable.
We present the one-loop corrected decay widths for the decays of the neutral Higgs bosons h^0, H^0, and A^0 into a neutralino pair neu_m neu_n (m, n = 1, >..., 4) and to the decay neu_m -> (h^0, H^0, A^0) + neu_n. The corrections contain the one-loop contributions of all fermions and sfermions. All parameters are taken on-shell. This requires a proper treatment of the neutralino mass and mixing matrix. The dependence on the SUSY parameters is discussed. The corrections can be large in certain regions of the parameter space.
We study the CP even trilinear neutral gauge boson vertices at one-loop in the context of the Standard Model and the Minimal Supersymmetric Standard Model, assuming two of the vector bosons are on-shell. We also study the changes in the form-factors when these two bosons are off-shell.
We investigate the contributions of neutral Higgs bosons to nonleptonic transition $b \to q \bar{s} s, q=d, s$ under the supersymmetric context. Their effects to decay width and CP violation in corresponding exclusive decays are explored. The anomalous dimension matrices of the operators which have to be incorporated to include the contributions of neutral Higgs bosons are given. We find that when tan$β$ is large (say, 50) and neutral Higgs bosons are not too heavy (say, 100 GeV), contributions of neutral Higgs penguin can dominate electroweak penguin contributions, and for some processes, the…
In the minimal supersymmetric standard model (MSSM), the neutralinos, the spin--1/2 Majorana superpartners of the neutral gauge and Higgs bosons, are expected to be among the light supersymmetric particles that can be produced copiously at future high--energy colliders. We analyze two--body neutralino decays into a neutralino plus a $Z$ boson or a lightest neutral Higgs boson $h$, allowing the relevant parameters to have complex phases. We show that the two--body tree--level decays of neutralinos are kinematically allowed in a large region of the MSSM parameter space and they can provide us wi…
A weakly coupled new neutral gauge boson, forming a narrow resonance, can be efficiently produced at e+e- colliders through radiative return processes if the collider energy is larger than the gauge boson mass. This contribution analyzes the sensitivity of a future linear collider for weakly coupled gauge bosons and briefly discusses how, in case of discovery, its properties can be determined with high precision.
We replace the scalar Higgs doublet with a vector Higgs boson doublet to the unified electroweak W-S model and find most of important features of W-S model are kept unchanged only the Higgs boson now become vector bosons. Lorentz invariance has been carefully discussed. The most important challenge is there will be three massless vector Higgs bosons. The remarkable effect is the possible suppression of the flavorchanging neutral current compare to the multi-Higgs model.
The two--loop mechanism of Bjorken and Weinberg is used to constrain flavor changing neutral Higgs bosons. We calculate the complete set of two--loop diagrams for the rare decay $μ\rightarrow e + γ$ induced by such neutral Higgs bosons, for arbitrary Higgs and top masses. The analytic result is used to set limits on Higgs masses for some recent models with specific ansatz about the flavor changing couplings. For example, in the Cheng--Sher scenario of multi-Higgs doublet models, all neutral Higgs bosons possess flavor changing ($f_i \leftrightarrow f_j)$ couplings proportional to $\sqrt{m_i m_…
We study the associated production of a CP-odd Higgs boson $A^0$ with a neutral gauge boson ($Z$ or photon) in high-energy $e^+ e^-$ collisions at the one-loop level in the framework of Two Higgs Doublet Models (THDM). We find that in the small $\tanβ$ regime the top quark loop contribution is enhanced leading to significant cross-sections (about a few fb), while in the large $\tanβ$ regime the cross-section does not attain observable rates.
The theory for Bose-Einstein correlations in case of neutral gauge bosons in $pp$ collisions at high energies is presented. Based on quantum field theory at finite temperature the two-particle Bose-Einstein correlations of neutral gauge bosons are carried out for the first time. As a result, the important parameters of the correlation functions can be obtained for the $Z^{0}Z^{0}$ pairs. The correlations of two bosons in 4-momentum space presented in this paper offer useful and instructive complimentary viewpoints to theoretical and experimental works in multiparticle femtoscopy and interferom…
We examine how the abilities of an SDC-like detector to discover and identify the origin of a new neutral gauge boson are affected by $Z_1-Z_2 $ mixing and by variations in detector parameters such as lepton pair mass resolution, particle identification efficiency, and rapidity coverage. Also examined is the sensitivity of these results to variations in structure function uncertainties and uncertainties in the machine integrated luminosity. Such considerations are of importance when dealing with the issues of detector descoping and design.
In the framework of Minimal Supersymmetric Standard Model Higgs bosons production via gluino/squark loop in the processes $gu \to H^{+}d$, $gd \to H^{-}u$,$gq \to H^{0}_iq$ are studied.
We investigate the pseudoscalar neutral Higgs-boson A^0 production in the polarized (gamma e) collisions with two different center of mass energies sqrt{s} = 500 GeV and sqrt{s} = 1 TeV. The cross-section of the process (gamma e -> e A^0) and the polarization asymmetry due the spin of the initial beams are calculated.
We study the possibility of discovering neutral scalar Higgs bosons in the $U(1)'$-extended supersymmetric standard model (USSM) at the CERN Large Hadron Collider (LHC), by examining their productions via the exotic quark loop in the gluon fusion process at leading order. It is possible in some parameter region that the neutral scalar Higgs bosons may have stronger couplings with the exotic quarks than with top quark. In this case, the exotic quarks may contribute more significantly than top quark in productions of the neutral scalar Higgs bosons in the gluon fusion process. We find that there…
In this work, the following reactions have been studied: $e^- e^+ \to H^- \widetildeχ_{1}^+ \widetildeχ_{1}^o$, $e^{-}e^{+}\to h\widetildeχ_{1}^{+}\widetildeχ_{1}^{-}$, $e^{-}e^{+}\to h\widetildeχ_{1}^{o}\widetildeχ_{1}^{o}$, $e^{-}e^{+}\to h H^{+} H^{-}$, where $\widetildeχ_{1}^{\pm}$ is the chargino and $\widetildeχ_{1}^{0}$ is the neutralino. $h$ represent the lightest neutral Higgs boson, and $H_3$ (sometimes refered to as $A$) is the pseudoscalar Higgs boson. The work went to calculate the differential cross section due to each Feynman diagram, then, the total cross section for each react…
We study the phenomenology of the neutral Higgs sector of a non-SUSY non-minimal Standard Model. Models with more than one Higgs doublet are possible, and may contain neutral Higgs scalars with branching ratios significantly different to those of the Minimal Standard Model Higgs boson. We show how these differences may be exploited at LEP2 in order to distinguish the non-minimal Standard Model from the minimal version.
The neutral Higgs sector of the minimal supersymmetric standard model (MSSM) in explicit CP violation scenario is investigated at the one-loop level. Within the context of the effective potential formalism, the masses of the neutral Higgs bosons are calculated at the one-loop level by taking into account the contributions of the following loops of ordinary particles and superpartners: top quark, the scalar top quarks, bottom quark, the scalar bottom quarks, tau lepton, the scalar tau leptons, $W$ boson, the charged Higgs boson, the charginos, $Z$ boson, the scalar and pseudoscalar Higgs bosons…
We show that large ($> 100$ GeV) mass splittings between the charged Higgs boson ($H^\pm$) and the neutral Higgs bosons ($H^0$ and $A^0$) are possible in the Minimal Supersymmetric Standard Model (MSSM). Such splittings occur when the $μ$ parameter is considerably larger than the common SUSY scale, $M_{SUSY}$, and have significant consequences for MSSM Higgs searches at future colliders.
We consider a particular two-Higgs-doublet model with spontaneous CP violation, where two neutral Higgses have no definite CP properties and the third one is CP-even. In this model, as the parameter $θ$ of CP violation increases, the masses of the neutral Higgs bosons are drawn towards the mass of the lightest one and the chance of detection of neutral Higgses at an $e^+e^-$ collider in Z+Higgs, $b\bar{b}$+Higgs and $t\bar{t}$+Higgs production increases with respect to the CP conserving case.
We consider two recently accentuated, unusual empirical results concerning cosmic-ray events at high energies. We show that the possibility for a correlated explanation is provided by new dynamics which arises from collisions of a neutral Goldstone boson as a component of the highest-energy cosmic rays.
The phenomenology of the neutral scalar bosons in the compact 341 model is discussed. We show that the predictions of this model are fairly good and compatible with the experimental data by calculating the signal strength of $h_1$ for the channels $b\bar{b}$, W$W^{*}$, Z$Z^{*}$, $τ\barτ$ and $γγ$. Moreover, we use the branching ratios to search for the heavy neutral scalar bosons $h_2$ and $h_3$ where we take into account the theoretical constraints to precise the allowed ranges for the fundamental parameters of the scalar potential.
A light neutral Higgs boson in the framework of the general two Higgs doublet model (2HDM) is not excluded by existing data. We point out that it can be looked for at the proposed low energy $γγ$ collider. Failure to detect one may lead to important limits on the parameters of the general 2HDM.
We consider the measurement of the trilinear couplings of the neutral Higgs bosons~($H^0, h^0$) in the minimal supersymmetric standard model~(MSSM) at a high energy $e^+$ $e^-$ linear collider in the light of the discovery of a Higgs boson at the CERN Large Hadron Collider~(LHC). We identify the state observed at the LHC with the lightest CP-even Higgs boson of the MSSM. We implement this constraint, as well as all the other relevant experimental constraints, on the parameter space of the MSSM in order to study the feasibility of measuring the trilinear couplings of the neutral Higgs bosons. F…
Multiple production of Higgs particles is essential to study Higgs self-couplings at future high-energy colliders. In this paper we calculated the resonance contributions to the production of three lightest neutral supersymmetric Higgs bosons in gluon fusion at LHC. The cross sections due to trilinear Higgs couplings is sizeable but the measurement of the quartic coupling hhhH(h) seems to be impossible.
The phenomenology of neutral Higgs bosons from non--SUSY, extended Higgs sectors is studied in the context of the LHC, with particular attention given to the case of a fermiophobic Higgs. It is found that enhanced branching ratios to $γγ$ and $τ^+τ^-$ are possible and can provide clear signatures, while detection of a fermiophobic Higgs will be problematic beyond a mass of 130 GeV.
We revisit the neutral Higgs sector of the Higgs Triplet Model, with non-negligible mixing in the CP-even Higgs sector. We examine the possibility that one of the Higgs boson state is the particle observed at the LHC at 125 GeV, and the other is either the small LEP excess at 98 GeV; or the CMS excess at 136 GeV; or that the neutral Higgs bosons are (almost) degenerate and have both mass 125 GeV. We show that, under general considerations, an (unmixed) neutral Higgs boson cannot have an enhanced decay branching ratio into gamma gamma with respect to the Standard Model one. An enhancement is ho…
We perform the comprehensive analysis of the polarization effects on the e^+e^- -> W^+W^- process in the presence of the extra neutral gauge boson at the LC energies. Consideration of the polarizations of the produced W bosons and the beam polarizations provides substantial enhancements of the sensitivity to the Z-Z' mixing angles in various models and the asymmetry variables also give the strict constraints on the mixing angles. We find that the χ-model and the left-right model get the strict constraint from σ_{LL}^{unpol} while the ψ-model and the η-model from the beam polarization asymmetry…
We have computed the two-loop, electroweak corrections to the production of a light and a heavy neutral, scalar Higgs-boson through the important gluon fusion process in the Two-Higgs-Doublet Model. We provide our results in various renormalization schemes for different scenarios and benchmark points, which will be valuable for experimental studies at the LHC. We describe the technicalities of our two-loop calculation and augment it by a phenomenological discussion. Our results are also applicable to the gluonic neutral, scalar Higgs-boson decays.
We study the CP violating asymmetry, the forward-backward asymmetry of the lepton pair and the CP asymmetry in the forward backward asymmetry for the exclusive decay $B --> K^* τ^+ τ^- in the general two Higgs doublet model including the neutral Higgs boson effects. We analyse the dependencies of these quantities on the model III parameters. We found that the physical parameters studied above are at the order of the magnitude 1% and neutral Higgs boson effects are detectable for large values of the coupling \barξ_{N,ττ}^D.
By using a simple thermodynamical method we confirm the finding of Chavanis and Harko that stable Bose-Einstein condensate stars can form. However, by using a thermodynamically consistent boson equation of state, we obtain a less massive Bose-Einstein condensate star compared to the one predicted by Chavanis and Harko. We also obtain that the maximum mass of a boson star is insensitive to the change of matter temperature. However, the mass of boson star with relatively large radius depends significantly on the temperature of the boson matter.
We compute the one loop new physics effects to the CP even triple neutral gauge boson vertices $γ^\star γZ$, $γ^\star Z \,Z$, $Z^\star \,Z\,γ$ and $Z^\star\,Z\,Z$ in the context of Little Higgs models. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a' and compare with the SM and Little Higgs models.
The neutral Higgs sector of the next-to-minimal supersymmetric standard model (NMSSM) with explicit CP violation is investigated at the 1-loop level, using the effective potential method; not only the loops involving the third generation of quarks and scalar quarks, but also the loops involving $W$ boson, charged Higgs boson, and chargino are taken into account. It is found that for some parameter values of the NMSSM the contributions from the $W$ boson, charged Higgs boson, and chargino loops may modify the masses of the neutral Higgs bosons and the mixings among them significantly, depending…
We explore the physics of a new neutral gauge boson, ($Z^\prime$), coupling to only third-generation particles with a mass near the electroweak gauge boson mass poles. A $Z^\prime$ boson produced by top quarks and decaying to tau leptons is considered. With a simple search strategy inspired by existing analyses of the standard model gauge boson production in association with top quarks, we show that the Large Hadron Collider has good exclusionary power over the model parameter space of the $Z^\prime$ boson even at the advent of the high-luminosity era. It is shown that the $t\bar{t}Z^\prime$ p…
Diagrammatic two-loop results are presented for the leading QCD corrections to the masses of the neutral CP-even Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM). The results are valid for arbitrary values of the parameters of the Higgs and scalar top sector of the MSSM. Their impact on a precise prediction for the mass of the lightest Higgs boson is briefly discussed.
In this paper, the b quark pair production events are analyzed as a source of neutral Higgs bosons of the two Higgs doublet model type I at linear colliders. The production mechanism is e+e- -> Z/gamma -> HA -> bbbb assuming a fully hadronic final state. The analysis aim is to identify both scalar and pseudo-scalar Higgs bosons in different benchmark points accommodating moderate boson masses. Due to pair production of Higgs bosons, the analysis is most suitable for a linear collider operating at sqrt(s) = 1 TeV. Results show that in selected benchmark points, signal peaks are observable in th…
With the advent of the ability to create and study antihydrogen, we think it is appropriate to consider the possibility that antiphotons might not be identical to photons. First of all, we will look at the experimental evidence concerning multiple neutral pions and multiple photons. Because of its internal structure, the neutral kaon is not identical to its antiparticle. We will consider internal structures for the neutral pion and photon for which the antiparticle differs from the particle. Interestingly, the antiphoton thus created from neutrinos does not interact with electrons because its …
We provide a full one-loop calculation of the self energies and tadpoles of the neutral Higgs bosons of the NMSSM. In addition, we compute the two-loop O(alpha_t*alpha_s+alpha_b*alpha_s) corrections to the neutral Higgs boson masses in the effective potential approximation. With respect to earlier calculations, the newly-computed corrections can account for shifts of a few GeV in the light scalar and pseudoscalar masses, and they can also sizeably affect the mixing between singlet and MSSM-like Higgs scalars. Taking these corrections into account will be crucial for a meaningful comparison bet…
We review the comparison of the results for the neutral CP-even Higgs-boson masses recently obtained within the Feynman-diagrammatic approach with the previous results based on the renormalization group approach. We show that the results differ by new genuine two-loop contributions present in the Feynman-diagrammatic calculation. The numerical effect of these terms on the result for m_h is briefly discussed.
In this paper, we review the production cross section for charged and neutral Higgs bosons pairs in $e^{+}e^{-}$ collisions beyond the tree level, in the framework of the Minimal Supersymmetric Standard Model (MSSM). A complete list of formulas for all electroweak contributions at the one loop level is given. A numerical code has been developed in order to compute them accurately and, in turn, to compare the MSSM Higgs bosons pair production cross sections at tree level and at the one loop level.
We review the phenomenology of light Higgs scalars in supersymmetric left-right models. We consider models with minimal particle content (with and without non-renormalizable higher-dimensional terms) and with additional Higgs superfields. The upper bound on the lightest CP-even neutral Higgs boson in these models is larger than in the minimal supersymmetric standard model, and the Higgs couplings to fermions approach those of the Standard Model. Possibly light doubly charged Higgs boson may provide the best signature of these models.
Small neutrino masses can arise in some grand unified models or superstring theories. We consider a model with an enhanced fermion sector containing Dirac neutral heavy leptons. The dependence on the mass and mixing parameters of these new fermions is investigated for several measurable quantities. We study the flavor-conserving leptonic decays of the Z boson and universality breaking in these decays. We also consider the W boson mass dependence on neutral heavy lepton parameters.
Neutral Higgs-boson pair production provides the possibility of studying the trilinear Higgs couplings at future high-energy colliders. We present the QCD corrections to the gluon-initiated processes in the limit of a heavy top quark in the loops and the Drell-Yan-like pair production of scalar and pseudoscalar Higgs particles. The pp cross sections are discussed for LHC energies within the Standard Model and its minimal supersymmetric extension. The QCD corrections are large, enhancing the total cross sections significantly.
In the framework of the Inert Higgs Doublet model (IHDM), we have investigated, in the center of mass frame, the neutral Higgs-boson pair production in the presence of an intense and circularly polarized laser field via ${e}^{+} {e}^{-}$ annihilation $({e}^{+} {e}^{-}\rightarrow H^{0}A^{0})$ at the lowest order. By using the scattering matrix method, we have derived the analytical expression of the differential cross section. The latter is numerically integrated over the solid angle to obtain the total cross section. Then, we have shown how this total cross section depends on the outgoing part…
We consider the measurement of the trilinear couplings of the neutral Higgs bosons in the Minimal Supersymmetric Standard Model~(MSSM) at a high energy $e^+ e^-$ linear collider in the light of the discovery of a Higgs boson at the CERN Large Hadron Collider~(LHC). We identify the state observed at the LHC with the lightest Higgs boson~($h^0$) of the MSSM, and impose the constraints following from this identification, as well as other experimental constraints on the MSSM parameter space. In order to measure trilinear neutral Higgs couplings, we consider different processes where the heavier Hi…
With $μ\to eγ$ decay forbidden by multiplicative lepton number conservation, we study muonium--antimuonium transitions induced by neutral scalar bosons. Pseudoscalars do not induce conversion for triplet muonium, while for singlet muonium, pseudoscalar and scalar contributions add constructively. This is in contrast to the usual case of doubly charged scalar exchange, where the conversion rate is the same for both singlet and triplet muonium. Complementary to muonium conversion studies, high energy $μ^+e^- \to μ^- e^+$ and $e^-e^- \to μ^- μ^-$ collisions could reveal spectacular resonance peak…
We analyze the correlation of QCD one-loop effects on the partial widths of the three neutral Higgs bosons of the MSSM decaying into quark-antiquark pairs. The SUSY-QCD effects turn out to be comparable or even larger than the standard QCD effects and are slowly decoupling in a wide window of the parameter space. Our study is aimed at elucidating the possible supersymmetric nature of the neutral Higgs bosons that might be discovered in the near future at the Tevatron and/or at the LHC. In particular, we point out the presence of potentially large SUSY corrections to the various neutral Higgs p…
We investigate the CP violating form factor of the ZZZ$ and $ZZγ$ vertices in the pair production of $Z^0$ bosons. Useful observables in azimuthal distributions are constructed to probe $CP$ nonconservation which may originate from these vertices. A simple Two Higgs Model of $CP$ violation is used as an illustration.
We show that a supersymmetric neutral Higgs boson with a mass of about 115 GeV and with the other prerequisites required by the LEP Higgs events would be compatible with the detection of relic neutralinos in current set-ups for WIMP direct search. Thus this putative Higgs would fit remarkably well in an interpretation in terms of relic neutralinos of the annual-modulation effect recently measured in a WIMP direct experiment. We also show that the cosmological abundance of the relevant neutralinos reaches values of cosmological interest.
