Search

Models with extra gauge bosons are well motivated extensions of the standard model (SM) because of their connection with several unification schemes. These models include an extended Higgs sector in order to break the gauge symmetry and generate the required masses. The resulting spectrum of Higgs bosons could be searched for at current and future colliders using SM-like production mechanisms. However, the existence of the new gauge bosons could provide new production mechanisms, which could be used to probe the non-standard properties of Higgs particles. In this paper, we study the 3-body decays of the Z′ associated with a model with an extra U(1)′, which could be used as a source of Higgs bosons. We find that the decays of a Z′ into a Higgs boson and a top–anti-top pair, namely , can reach branching ratios (Br′s) as high as 10−3, which could be detected at future colliders. We also study the production of Higgs bosons in association with the Z vector boson at a linear collider, through the reaction e+e− → Z, Z′ → Z + h, including both the resonant and non-resonant effects. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider (LHC), now close to completion at CERN will provide proton-proton collisions with unprecedented luminosity and energy. It will allow the Standard Model of physics to be explored in an energy range where new phenomena can be studied. This includes the validity of the Higgs mechanism, supersymmetry and CP violation. The machine presents a number of novel features discussed in detail below. [ABSTRACT FROM AUTHOR]

In this study, assuming the type-I 2HDM at standard model-like scenario, observability of heavy neutral CP-even and CP-odd Higgs bosons H and A at a linear collider operating at TeV is investigated through the signal process chain where the Z boson experiences a leptonic ( or ) decay and the H Higgs boson is assumed to decay into a di-photon. This signal process is motivated especially by the clean signature which leptonic and photonic events can provide at colliders, and also by the enhancement due to the charged Higgs-mediated contribution to H di-photon decay at large values. The simulation is based on four benchmark points according to which the Higgs mass mH (mA) varies within the range 150–300 (200–400) GeV. Energy smearing of jets and photons is performed, and momentum smearing is also applied to leptons. Results indicate that, for all of the assumed benchmark points, the Higgs bosons H and A are observable with measurable masses, and with signals exceeding 5σ at integrated luminosities 99 and , respectively. Such luminosities are easily accessible to future linear colliders. [ABSTRACT FROM AUTHOR]

The Circular Electron–Positron Collider (CEPC) is a future Higgs factory proposed by the Chinese high energy physics community. It will operate at a center-of-mass energy of 240–250 GeV. The CEPC will accumulate an integrated luminosity of 5 ab in ten years’ operation. With GEANT4-based full simulation samples for the CEPC, the Higgs boson decaying into an electron pair is studied at the CEPC. The upper limit of could reach 0.024% at 95% confidence level. The signal process is generated by MadGraph, with initial state radiation implemented6, as a first step to adjusting MadGraph for an electron–positron collider. [ABSTRACT FROM AUTHOR]

The gauge extension of the standard model with thesymmetry predicts the existence of a light gauge bosonwith small couplings to ordinary fermions. We discuss its contributions to the muon anomalous magnetic moment . Taking account of the constraints on the relevant free parameters, we further calculate the contributions of the light gauge bosonto the Higgs-strahlung processesand . [ABSTRACT FROM AUTHOR]

A detection at the large hadron collider of a light Higgs pseudoscalar would, if interpreted in a supersymmetric framework, be a smoking gun signature of non-minimal supersymmetry. In this work in the framework of the next-to-minimal supersymmetric standard model we focus on vector boson fusion and Higgs-strahlung production of heavier scalars that subsequently decay into pairs of light pseudoscalars. We demonstrate that although these channels have in general very limited reach, they are viable for the detection of light pseudoscalars in some parts of parameter space and can serve as an important complementary probe to the dominant gluon-fusion production mode. We also demonstrate that in a Higgs factory these channels may reach sensitivities comparable to or even exceeding the gluon fusion channels at the Large Hadron Collider, thus possibly rendering this our best option to discover a light pseudoscalar. It is also worth mentioning that for the singlet dominated scalar this may be the only way to measure its couplings to gauge bosons. Especially promising are channels where the initial scalar is radiated off a W as these events have relatively high rates and provide substantial background suppression due to leptons from the W. We identify three benchmark points that well represent the above scenarios. Assuming that the masses of the scalars and pseudoscalars are already measured in the gluon-fusion channel, the event kinematics can be further constrained, hence significantly improving detection prospects. This is especially important in the Higgs-strahlung channels with rather heavy scalars, and results in possible detection at 200 fb−1 for the most favoured parts of the parameter space. [ABSTRACT FROM AUTHOR]

The differential cross sections for Higgs-portal scalar singlet production following Higgs production in proton colliders are presented, using both the gluon fusion and electroweak vector boson fusion production mechanisms. The treatment is fully partonic, using the effective vector boson approximation to obtain parton distribution functions for electroweak vector bosons. Results are presented both in semi-analytic and numerical forms. We find that missing energy signatures of low mass singlets are far more likely to be observed than those of higher mass singlets, and that any signal observed will be peaked at zero singlet momentum. [ABSTRACT FROM AUTHOR]

The charged and doubly charged Higgs bosons ( and ) are the typical particles predicted by the Higgs triplet model (HTM) and the observation of these particles might be regarded as direct evidence of the HTM. In this paper, we investigate the pair production of the charged and doubly Higgs bosons at the International Linear Collider (ILC): and . We present the production cross sections and the distributions of the various observables, i.e., the distributions of the transverse momenta and the rapidity distributions for out-going particles. Our numerical results show that, as long as the charged and doubly charged Higgs bosons masses are not too heavy, their possible signals might be detected via these processes in future ILC experiments. A simply phenomenological analysis is also given. [ABSTRACT FROM AUTHOR]