We study the production and signatures of doubly charged Higgs bosons in the process γγH^{- -} H^{++} at the e^-e^+ International Linear Collider and CERN Linear Collider, where the intermediate photons are given by the Weizs[a\ddot]cker-Willians and laser backscattering distributions.
We point out that in a large class of supersymmetric left-right models with automatic R-parity conservation there are a pair of light doubly charged Higgs bosons and Higgsinos. Requiring the mass of these particles to satisfy the LEP Z-width bound implies that $W_R$ mass must be above $10^{9}$ GeV.
Several supersymmetric models with extended gauge structures, motivated by either grand unification or by neutrino mass generation, predict light doubly-charged Higgsinos. In this work we study the signals of doubly-charged Higgsinos at the Tevatron in both pair-- and single--production modes, and show that it is possible, especially from the events containing same-sign same-flavor isolated leptons, to disentangle the effects of doubly-charged Higgsinos in the Tevatron data.
Doubly charged Higgs bosons are very important in particle physics nowadays because they can give mass to neutrinos through seesaw mechanisms. In this work we present the results in the searching for doubly charged Higgs at the CERN LHC for a 3-3-1 model.
The Higgs sector of the standard model can be extended by introducing an $SU(2)_L$ Higgs triplet $Δ$ to generate the tiny neutrino masses in the framework of type-II seesaw mechanism. In this paper, we study the pair production of the introduced Higgs triplet at future $e^{-}p$ colliders. The corresponding production cross sections via vector boson fusion process at FCC-ep and ILC$\otimes$FCC are predicted, where the production of a pair of doubly charged Higgs is found to be dominant and then used to investigate the collider phenomenology of the Higgs triplet. Depending on the size of the Hig…
Production of doubly charged Higgs bosons via the s-channel process e-e- -> H-- -> l-l- at future linear collider energies is studied by taking into account initial state radiation (ISR) and beamstrahlung (ISR + BS), final state radiation (FSR) and detector smearing effects. The discovery bounds of lepton flavour conserving and violating couplings are obtained for doubly charged Higgs bosons. It is found that future linear colliders with centre of mass energies and will be able to probe the doubly charged Higgs bosons with diagonal couplings down to 10^-4 and 10^-3, respectively.
Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying their production and decay characteristics.
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 doubly charged Higgs bosons in the $e^-e^+$ International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.
Using a peculiar version of the SU(3)L x U(1)N electroweak model, we investigate the production of doubly charged Higgs boson at the Large Hadron Collider. Our results include branching ratio calculations for the doubly charged Higgs and for one of the neutral scalar bosons of the model.
We studied the production and signatures of doubly charged Higgs bosons in the process $γe^- \rightarrow H^{--}E^+$, where $E^+$ is a heavy lepton, at the $e^-e^+$ International Linear Collider (ILC) and CERN Linear Collider (CLIC). The intermediate photons are given by the Weizs$\ddot{a}$cker-Williams and laser backscattering distributions. We found that significant signatures are obtained by bremsstrahlung and backward Comptom scattering of laser. A clear signal can be obtained for doubly charged Higgs bosons, doubly charged gauge bosons and heavy leptons.
The Higgs triplet model (HTM) predicts the existence of a pair of doubly charged Higgs bosons $H^{\pm \pm}$. Single production of $H^{\pm \pm}$ via e collision at the next generation e+e- International Linear Collider (ILC) and the Large Hadron electron Collider (LHeC) is considered. The numerical results show that the production cross sections are very sensitive to the neutrino oscillation parameters. Their values for the inverted hierarchy mass spectrum are larger than those for the normal hierarchy mass spectrum at these two kinds of collider experiments. With reasonable values of the relev…
Doubly charged scalars, predicted in many models having exotic Higgs representations, can in general have lepton-number violating (LFV) couplings. We show that by using an associated monoenergetic final state photon seen at a future linear e-e- collider, we can have a clear and distinct signature for a doubly-charged resonance. The strength of the Delta L=2 coupling can also be probed quite effectively as a function of the recoil mass of the doubly-charged scalar.
We reconsider the single production of the doubly charged Higgs bosons Delta_R^{++} and Delta_L^{++} at the LHC and TEVATRON in the framework of the left-right symmetric model and the Higgs triplet model. We show that in the left-right symmetric model the production of Delta_R^{++} by Drell-Yan process via W_R exchange may give the dominant contribution. The same channel for the production of Delta_L^{++} in the Higgs triplet model is insignificant.
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.
In supersymmetric grand unified theories, light higgsino multiplets generally exist in addition to the familiar chargino/neutralino multiplets of the minimal supersymmetric extension of the Standard Model. The new multiplets may include doubly charged states $\tildeΔ^{\pm\pm}$ and $\tildeδ^{\pm\pm}$. We study the properties and the production channels of these novel higgsinos in $e^+e^-$ and $γγ$ collisions, and investigate how their properties can be analyzed experimentally.
We studied the signatures of an electroweak SU(2) lepton triplet which contains a doubly charged heavy lepton. The most interesting and easily detected final states are originating from the doubly charged lepton pair and single production, that we analyzed at a center of mass energy of 14 TeV. We propose useful kinematic cuts to reduce the backgrounds and computed the integrated luminosity needed to discover or exclude the doubly charged leptons for various masses.
The production of a single exotic Higgs particle is studied at Hera. Within the present limits on the Yukawa couplings this doubly charged particle, suggested by the left-right symmetric models, can be observed at Hera up to values of its mass of about 150 GeV.
We analyze the next-to-leading order QCD corrections to the production of doubly-charged Higgs particles at hadron colliders in extensions of the SM with Higgs isospin triplets. At both the Tevatron and the LHC, these corrections are found to be moderate in size increasing the cross sections by about 20--30%. The residual theoretical uncertainties are of the order of 10--15% which is sufficient for experimental searches for these particles at the Tevatron and LHC.
We studied the signatures at the LHC of the electroweak SU(2) lepton doublet which embeds a doubly charged lepton. The doubly charged lepton pair and single production rates, which are different from the triplet case, are studied and all the detectable decay modes are considered. We also applied the same kinematic cuts as in triplet case to reduce the background at LHC and the needed integrated luminosities to find the doubly charged leptons with different masses are analyzed. We also suggested a method to distinguish the exotic lepton doublet and triplet.
The rate for the lepton-number-violating decay K+ to pi- mu+mu+ is calculated in a model which incorporates doubly-charged Higgs bosons. We find that for reasonable values of the parameters the decay branching ratio may be as large as 2E-16. Although this is a discouragingly small number, it is of the same order of magnitude as the rate mediated by massive Majorana neutrinos.
Production of a single doubly charged Higgs boson $Delta^{--}$ in polarized $e^+e^-$ and $e^+γ$ collision modes of the linear collider have been investigated. The mass range of $Delta^{--}$ to be probed extends up to the collision energy. The diagonal lepton number violating Yukawa coupling $h_{ee}$ will be tested at least three orders of magnitude more strictly than in present experiments.
Several extended supersymmetric models, motivated by either grand unification, or by neutrino mass generation, predict light doubly charged higgsinos. We study the production of a single doubly charged higgsino and its decay channels at the International Linear Collider (ILC) operating in the e-e- mode. We analyze the production cross section for e-e- --> tilde{Delta}^{--}_{L,R} chi^0_1 as a function of different kinematic variables, followed by the decay, through several channels, of the doubly charged higgsino into a final state of two leptons plus missing energy. We include the standard mod…
In the framework of Higgs triplet model (HTM), we study the pair production process of doubly charged Higgs bosons via $e^{+}e^{-}$ annihilation in the presence of a laser field with circular polarization . We begin our work by presenting the theoretical calculation of the differential cross section in the centre of mass frame including both $Z$ and $γ$ diagrams. Then, from the numerical analysis of the production cross section's dependence on the laser field parameters, we have shown that the laser-assisted total cross section decreases as far as the electromagnetic field intensity enhances o…
We estimate the potential for observation at the LHC of a doubly charged Higgs boson, as predicted in Left-Right symmetric models. Single production by vector boson fusion, $W^+W^+ \to Δ_{L,R}^{++}$ and pair production by the Drell-Yan process $q \bar q \to Δ_{L,R}^{++}Δ_{L,R}^{--}$ are considered. Various decay channels are investigated: dileptons, including pairs of $τ$'s, as well as $WW$
We study a model with Majorana neutrino masses generated through doubly charged scalars at two-loop level. We give explicit relationships between the neutrino masses and the same sign dilepton decays of the doubly charged scalars. In particular, we demonstrate that at the tribimaximal limit of the neutrino mixings, the absolute neutrino masses and Majorana phases can be extracted through the measurements of the dilepton modes at colliders.
Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly charged scalars assuming they decay promptly and exclusively into charged leptons. Our study focuses on the fit to the same-sign dilepton mass spectra and it is based on proton-proton collisions at $13$ TeV, $14$ TeV and $27$ TeV with integrated luminosity of $\mathcal{L}=139 fb^{-1}, 3 $ab$^{-1}$ and $15$ab$^{-1}$. We find that HL-LHC may probe doubly charge…
Rates for productions of neutral and doubly charged partners of D_{s0}^+(2317) in B meson decays are studied by using a hard D meson approximation in the infinite momentum frame, and the results are of the same order of magnitude as that of D_{s0}^+(2317). Because the bottom-strange X^{+-}(5568) which can be interpreted as iso-triplet bottom partners of D_{s0}^+(2317) have recently been discovered, observations of neutral and doubly charged partners of D_{s0}^+(2317) are strongly desired.
It is suggested that the observed excess of muons in studies of $p \bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV arises from the decay of doubly-charged bosons. Such particles are predicted in the 3-3-1 model where the electroweak gauge group is extended to $SU(3) \times U(1)$.
The lepton-number-violating decays of $B^+, D^+$ and $D_s^+$ mesons induced by the doubly charged Higgs boson have been studied. It is found that although the yielded results of the branch ratio are much smaller than the present limits from the data they are consistent with the previous conclusions calculated in the framwork of relativistic quark model where the processes happened via the light Majorana neutrinos.
We search for lepton flavour violating couplings via doubly charged bilepton (or doubly charged Higgs) exchange in electron-positron annihilation process $ \text{e}^{+}\text{e}^{-}\to μ^{+}μ^{-}, τ^{+}τ^{-}$ using CERN LEP data at the center of mass energies between 189-207 GeV. Standard model program ZFITTER has been used to calculate radiative corrections. We find that $g_{L}^{2}/M_{L}^{2}<O(10^{-6})GeV^{-2}$ at 95% C.L. for flavour violating scalar and vector bilepton couplings.
We present a detailed and complete calculation of the doubly charged Higgsino contribution to the decays mu--> e photon and mu--> 3e and to the anomalous magnetic moment of the muon within the left-right supersymmetric model. We include the mixing of the scalar partners of the left and right handed leptons, and show that it leads to a strong enhancement of the decay modes in certain scenarios. We find that the contribution of the doubly charged Higgsino can be close to the known experimental values and are reachable by future experiments.
We study the production of doubly charged excited leptons at the LHC. These exotic states are predicted in extended weak isospin composite models. A recent analysis of such exotic states was based on a pure gauge model with magnetic type interactions. We include here the mechanism of contact interactions and show that this turns out to dominate the production of the doubly charged leptons. We perform a feasibility analysis of the observation of the tri-lepton signature associated with the production of the exotic doubly charged lepton simulating the response of a generic detector. We give excl…
We study the leptonic decays of a doubly charged Higgs bosons class which is predicted by a model based on the SU(3)_C\otimesSU(2)_L\otimesU(1)_N electroweak gauge symmetry. In contrast to other models, decays into taus are largely dominant (99.5 % or more). Coupling of these scalars to two standard charged gauge bosons are either zero or very suppressed. Couplings to two different flavor of charged leptons do not occur. Some coupling features imposed by symmetry and representation content lead to simple relationships between decay rates and doubly charged Higgs masses. Some of the parameters …
The Higgs Triplet Model (HTM) of neutrino mass generation predicts the existence of doubly charged Higgs bosons (H^{\pm\pm}). In the HTM a scalar eigenstate (H_2) is dominantly composed of the scalar field from the isospin doublet, and could be significantly heavier than H^{\pm\pm}. Such a scenario would allow the possibility of a large branching ratio for the decay H_2-> H^{++}H^{--}. From the production mechanism of gluon-gluon fusion, gg-> H_2, the above decay mode would give rise to pair production of doubly charged Higgs bosons (H^{++}H^{--}) with a cross section which could be significan…
We discuss the possibility of observing doubly charged Higgs bosons in $γγ$ collisions. We find that one can increase the range of observability close to the kinematic limit by a judicious choice of the polarisations of the initial $e^-/ e^+$ beams as well as the initial laser beam photons which are made to back-scatter from the former. We also note that, in a large region of parameter space, the generally used lepton number violating decay mode is dominated by the decay into a singly charged Higgs and a real or virtual $W$-boson, giving rise to a large number of fermions in the final state. T…
Upper limits on doubly charged bilepton couplings and masses are extracted from LEP data for Bhabha scattering at energy range $\sqrt{s}=183-202$ GeV using standard model program ZFITTER which calculates radiative corrections. We find that $g_{L}^{2}/M_{L}^{2}<O(10^{-5})GeV^{-2}$ at 95% C.L. for scalar and vector bileptons.
Several supersymmetric models with extended gauge structures, motivated by either grand unification or by neutrino mass generation, predict light doubly-charged Higgsinos. In this work we study productions and decays of doubly-charged Higgsinos present in left-right supersymmetric models, and show that they invariably lead to novel collider signals not found in the minimal supersymmetric model (MSSM) or in any of its extensions motivated by the μproblem or even in extra dimensional theories. We investigate their distinctive signatures at the Large Hadron Collider (LHC) in both pair-- and singl…
We consider a fermionic dark matter (DM) in the left-right symmetric framework by introducing a pair of vector-like (VL) doublets in the particle spectrum. The stability of the DM is ensured through an unbroken $\mathcal{Z}_2$ symmetry. We explore the parameter space of the model compatible with the observed relic density and direct and indirect detection cross sections. The presence of charged dark fermions opens up an interesting possibility for the doubly charged Higgs signal at LHC and ILC. The signal for the doubly charged scalar decaying into the dark sector is analyzed in multilepton fi…
Doubly charged Higgs s-channel resonances are analyzed in the $e^-e^- \to W^-W^-$ process. In our analysis recent stringent constraint on an effective neutrino mass $<m_ν>$ coming from neutrinoless double-$β$ decay is implemented. It is shown that due to a very restrictive limit on $<m_ν>$ the doubly charged Higgs resonance predicted by the Standard Model with additional Higgs triplets is below the detection limit. For the same reason also the $Δ_L^{--}$ resonance can not be visible in the framework of the conventional Left-Right symmetric model. The situation is quite different for the $Δ_R^{…
In this work we investigate the production and signatures of doubly-charged particles at the Large Hadron Collider. We start with the Standard Model particle content and representations and add generic doubly-charged exotic particles. We classify these doubly-charged states according to their spin, considering scalar, fermionic and vectorial fields, and according to their SU(2)L representation, being chosen to be either trivial, fundamental, or adjoint. We write the most general interactions between them and the Standard Model sector and study their production modes and possible decay channels…
We discuss the parity-violating left-right asymmetries (LRAs) in Möller scattering at the International Linear Collider (ILC) induced by doubly charged Higgs bosons in models with $SU(2)_L$ triplet and singlet scalar bosons, which couple to the left- and right-handed charged leptons, respectively. These bosons are important in the scenarios for the generation of the neutrino mass. We demonstrate that the contributions to the LRAs from the triplet and singlet bosons are opposite to each other. In particular, we show that the doubly charged Higgs boson from the singlet scalar can be tested at th…
Doubly charged scalars, predicted in many models having exotic Higgs representations, can in general have lepton-number violating (LFV) couplings. The basis of most searches for this charged scalar has been to look for its direct production and its subsequent decay to like-sign final state leptons. In this work we show that by using an associated monoenergetic final state photon seen at a future linear e-e- collider, we can have a clear and distinct signature for a doubly-charged resonance and also determine its mass rather precisely. We also estimate the strength of the Delta L=2 coupling whi…
Single production of the doubly charged scalars $Φ^{\pm\pm}$ via $eγ$, $ep$ and $pp$ collisions is studied in the context of the little Higgs$(LH)$ model. Our numerical results show that the new particles $Φ^{\pm\pm}$ can be abundantly produced and their possible signatures should be detected in future high energy linear $e^{+}e^{-}$ collider$(ILC)$. The cross section for single production of $Φ^{\pm\pm}$ at the $LHC$ is much smaller than that at the $ILC$ or the $THERA$.
We present an analysis of supersymmetric left-right symmetric models with Higgs fields lying in the adjoint representation of $SU(2)_R$. These models feature a doubly-charged Higgs boson which gets its mass only at the loop level. We present, for the first time, a complete one-loop calculation of this mass and show that contributions that have been neglected so far can shift it by a few hundreds of GeV. We then combine this observation with LHC bounds deduced from extra charged gauge boson and doubly-charged Higgs boson searches. In particular, we point out that existing limits get substantial…
We study the sensitivity to doubly charged Higgs bosons, $Δ^{--}$, in the process $e^-γ\to e^+ μ^-μ^-$ for centre of mass energies appropriate to future high energy $e^+e^-$ collider proposals. For $M_Δ< \sqrt{s_{eγ}}$ discovery is likely for even relatively small values of the Yukawa coupling to leptons. However, even far above threshold, evidence for the $Δ$ can be seen due to contributions from virtual intermediate $Δ$'s although, in this case, $μ^-μ^-$ final states can only be produced in sufficient numbers for discovery for relatively large values of the Yukawa couplings.
We analyze the signal at the Tevatron for the doubly charged Higgs superfield of supersymmetric left-right models with gauge mediated supersymmetry breaking. Due to the presence of a new coupling, the lighter stau is usually less massive than the lightest neutralino and is frequently the NLSP. The fermionic part of the doubly charged Higgs field decays dominantly into two tau leptons plus missing energy (gravitino). We find that the inclusive two tau jets and three tau jets plus missing energy signatures could be observable at Run II of the Tevatron. We also find that the distribution in angle…
In this paper, we study the lepton number violation processes of $B_c$ meson induced by possible doubly-charged scalars. Both the three-body decay channels and the four-body decay channels are considered. For the former, $Br\times\left(\frac{s_Δh_{ij}}{M_Δ^2}\right)^{-2}$ is of the order of $10^{-7}\sim 10^{-9}$, and for the later channels, $Br\times\left(\frac{s_Δh_{ij}}{M_Δ^2}\right)^{-2}$ is of the order of $10^{-12}\sim 10^{-20}$, where $s_Δ$, $h_{ij}$, $M_Δ$ are the constants related to the doubly-charged boson.
Doubly charged Higgs bosons, H^{\pm\pm}, are being searched for in the Tevatron experiments. The most recent search by the D0 collaboration seeks three muons (mu^\pmμ^\pmμ^\mp), which are assumed to originate from the pair-production process, q\overline q\to H^{++}H^{--}, followed by the decay H^{\pm\pm} \to μ^\pm μ^\pm. In this three-lepton (3l) channel there are six distinct signatures for l=e or μ. In the context of the Higgs Triplet Model, we quantify the dependence of the event numbers for the 3l channels on the parameters of the neutrino mass matrix. It is also shown that the inclusion o…
The Georgi-Machacek model is one of many beyond Standard Model scenarios with an extended scalar sector which can group under the custodial $\rm SU(2)_C$ symmetry. There are 5-plet, 3-plet and singlet Higgs bosons under the classification of such symmetry in addition to the Standard Model Higgs boson. In this paper, we study the prospects for detecting the doubly-charged Higgs boson ($\rm H_5^{\pm\pm}$) through the vector boson fusion production at the electron-proton (ep) colliders. We concentrate on our analysis through $μ$-lepton pair production via pair of same-sign W bosons decay. The $\r…
We study lepton-number-violating (LNV) decays of heavy flavors ($τ$ lepton and top quark) induced by doubly-charged Higgs boson in the Higgs triplet model. It is found that the branching fractions of LNV $τ^- \to \ell^{+}M_1^-M_2^-$ decays are highly suppressed compared with the current experimental limits. On the other hand, for LNV top quark decays, the most optimistic branching ratios for $t \to b\ell^{+}\ell^{+}W^{-}$ turn out to be at the level of $\sim 10^{-7} - 10^{-8}$. The observation of these rare top quark decays would be a clear signal of LNV processes, and their non-observation wo…
We examine the slepton masses of SUSYLR models and how they change due the presence of light-doubly charged higgs bosons. We discover that the measurement of the slepton masses could bound and even predict the value of the third generation Yukawa coupling of leptons to the SU(2)_R Triplets. We also consider the unification prospects for this model with the addition of left-handed, B - L = 0 triplets--a model we call the Triplet Extended Supersymmetric Standard Model (TESSM). Finally, we discuss the changes in the slepton masses due to the presence of the SU(2)_L triplets.
We show that the accumulated LEP-II data taken at $\sqrt{s} =$ 130 to 206 GeV can establish more restrictive bounds on doubly charged bileptons couplings and masses than any other experiment so far. We also analyze the discovery potential of a prospective linear collider operating in both $e^+ e^-$ and $e γ$ modes.
The doubly charged Higgs bosons $Δ^{--}$ that are present in exotic Higgs representations can have lepton-number-violating couplings to $e^-e^-$. We discuss general constraints and phenomenology for the $Δ^{--}$ and demonstrate that extremely small values for the $e^-e^-\rightarrowΔ^{--}$ coupling (some 8 orders of magnitude smaller than the current limit) would produce observable signals for $Δ^{--}$ production in direct $s$-channel production at an $e^-e^-$ collider.
The Georgi-Machacek model is one of many beyond Standard Model scenarios with an extended scalar sector which can group under the custodial $\rm SU(2)_C$ symmetry. There are 5-plet, 3-plet and singlet Higgs bosons under the classification of such symmetry in addition to the Standard Model Higgs boson. Here we study the prospects for detecting the doubly-charged Higgs boson ($\rm H_5^{\pm\pm}$) through the vector boson fusion production at the electron-proton colliders. Typically, we concentrate on our analysis through $μ$-lepton pair production via pair of same-sign W bosons decay. The discove…
The doubly-charged scalar boson H^{--} is involved in several new physics models for generating neutrino masses. Depending on new physics models, H^{--} has the Yukawa interaction with a pair of left-handed charged leptons or a pair of right-handed ones. In this talk, we see that these two Yukawa interactions can be distinguished by measuring energy distributions of charged pions produced by decays of tau leptons if pair-produced H^{++} H^{--} can decay sufficiently into four charged leptons which involve one or two tau leptons. The information on the Yukawa interaction of H^{--} will help to …
We propose a new type of a three-loop induced neutrino mass model with dark matter candidates which are required for the neutrino mass generation. The smallness of neutrino masses can be naturally explained without introducing super heavy particles, namely, much heavier than a TeV scale and quite small couplings as compared to the gauge couplings. We find that as a bonus, the anomaly of the muon anomalous magnetic moment can simultaneously be explained by loop effects of new particles. In our model, there are doubly charged scalar bosons and leptons from isospin doublet fields which give chara…
We discuss a 331 model with three scalar triplets and neutral fermion singlets. We show that in the 331 model with right-handed neutrinos, it is possible to obtain small active neutrino masses via the double and inverse seesaw mechanisms, without the use of scalar sextets or triplets with doubly-charged Higgs. Two types of models are discussed. If we have a large Majorana mass matrix for the singlets, the spectrum of neutrinos presents light, heavy and very heavy masses. The other possibility is a small (zero) Majorana mass matrix, which leads to pseudo-Dirac (Dirac) heavy neutrinos in the TeV…
We study the pair production of doubly charged Higgs bosons at the Large Hadron Collider (LHC), assuming the doubly charged Higgs to be part of an SU(2)_L triplet which generates Majorana masses for left-handed neutrinos. Such pair-production has the advantage that it is not constrained by the triplet vacuum expectation value, which tends to make the single production rate rather small. We point out that, in addition to the Drell-Yan (DY) production mechanism, two-photon processes also contribute to H++H++ production at a level comparable to the QCD corrections to the DY channel. Decays of the…
We search for doubly charged scalar bileptons via $ \text{e}^{-}\text{e}^{-}\to μ^{-}μ^{-}$ and $ \text{e}^{-}\text{e}^{-}\to \text{e}^{-}\text{e}^{-}$ processes at linear collider energies by considering initial and final state electromagnetic radiative corrections (ISR, FSR). Moreover, smeared cross section is used for finite energy resolution. We show that ISR+FSR and smearing reduce cross sections remarkably depending on the smearing parameter due to narrow decay width of bileptons. We obtain realistic discovery contours of couplings and masses for the lepton flavour conserving and violati…