Charged Higgs Research Articles

Searches for Dark Matter via Mono-W Production in Inert Doublet Model at the LHC**Supported by the National Natural Science Foundation of China under Grant Nos. 11205003, 11305001, 11575002, the Key Research Foundation of Education Ministry of Anhui Province of China under Grant Nos. KJ2017A032, KJ2016A749, KJ2013A260, and Natural Science Foundation of West Anhui University under Grant No. WXZR201614

The Inert Doublet Model (IDM) is one of the many beyond Standard Model scenarios with an extended scalar sector, which provide a suitable dark matter particle candidate. Dark matter associated visible particle production at high energy colliders provides a unique way to determine the microscopic properties of the dark matter particle. In this paper, we investigate that the mono-W + missing transverse energy production at the Large Hadron Collider (LHC), where W boson decay to a lepton and a neutrino. We perform the analysis for the signal of mono-W production in the IDM and the Standard Model (SM) backgrounds, and the optimized criteria employing suitable cuts are chosen in kinematic variables to maximize signal significance. We also investigate the discovery potential in several benchmark scenarios at the 14 TeV LHC. When the light Z2 odd scalar higgs of mass is about 65 GeV, charged Higgs is in the mass range from 120 GeV to 250 GeV, it provides the best possibility with a signal significance of about 3σ at an integrated luminosity of about 3000 fb−1.

Charged Higgs production from polarized top-quark decay in the 2HDM considering the general-mass variable-flavor-number scheme

Charged Higgs bosons are predicted by some non-minimal Higgs scenarios, such as models containing Higgs triplets and two-Higgs-doublet models, so that the experimental observation of these bosons would indicate physics beyond the Standard Model. In the present work, we introduce a channel to indirect search for the charged Higgses through the hadronic decay of polarized top quarks where a top quark decays into a charged Higgs H+ and a bottom-flavored meson B via the hadronization process of the produced bottom quark, t(↑)→H++b(→B+jet). To obtain the energy spectrum of produced B-mesons we present, for the first time, an analytical expression for the O(αs) corrections to the differential decay width of the process t→H+b in presence of a massive b-quark in the General-Mass Variable-Flavor-Number (GM-VFN) scheme. We find that the most reliable predictions for the B-hadron energy spectrum are made in the GM-VFN scheme, specifically, when the Type-II 2HDM scenario is concerned.

Enhancement of new physics signal sensitivity with mistagged charm quarks

We investigate the potential for enhancing search sensitivity for signals having charm quarks in the final state, using the sizable bottom-mistagging rate for charm quarks at the LHC. Provided that the relevant background processes contain light quarks instead of charm quarks, the application of b-tagging on charm quark-initiated jets enables us to reject more background events than signal ones due to the relatively small mistagging rate for light quarks. The basic idea is tested with two rare top decay processes: i) t -> c h -> c b bbar and ii) t -> b H+ -> b bbar c where h and H+ denote the Standard Model-like higgs boson and a charged higgs boson, respectively. The major background source is a hadronic top quark decay such as t -> b W+ -> b sbar c. We test our method with Monte Carlo simulation at the LHC 14TeV, and find that the signal-over-background ratio can be increased by a factor of O(6-7) with a suitably designed (heavy) flavor tagging algorithm and scheme.

Some Decays of Neutral Higgs Bosons in the NMSSM

To solve the μ problem of the Minimal Supersymmetric Standard Model (MSSM), a single field S is added to build the Next Minimal Supersymmetric Standard Model (NMSSM). Vacuum enlarged with non-zero vevs of the neutral-even CP is the combination of Hu, Hd and S. In the NMSSM, the higgs sector is increased to 7 higgs (compared with 5 higgs in the MSSM), including three higgs which are even-CP h1,2,3(mh1 < mh2 < mh3), two higgs which are odd-CP a1,2(ma1 < ma2) and a couple of charged higgs H±. The decays higgs into higgs is one of the remarkable new points of the NMSSM. In this paper we study some decays of neutral Higgs bosons. The numerical results are also presented together with evaluations.

Charged Higgs production in association withW±at large hadron colliders

Many new physics models beyond the standard model, such as the littlest higgs models and the left right twin higgs models, predict the existence of the large charged higgs couplings H^-q\bar b and H^+b\bar q, where q=t or the new vector-like heavy quark T; On the other hand, some new physics models like the littlest higgs also predict the gauge-higgs couplings. Such couplings may have rich collider phenomenology. We focus our attention on these couplings induced by the littlest higgs models and the left right twin higgs models models and consider their contributions to the production cross section for W^\pm H^\mp production at the large hadron colliders. We find that the cross sections, in the littlest higgs models, on the parton level gg \to W^\pm H^\mp and q\bar q \to W^\pm H^\mp (q=u,d,s,c,b) may reach tens of several dozen femtobarns in reasonable parameters space at the collision energy of 14 TeV and that the total cross section can even reach a few hundred femtobarns in certain favored space. While in the left right twin higgs models, the production rates are basically one order lower than these in littlest higgs. Therefore, due to the large cross sections of that in the littlest higgs, it may be possible to probe the charged higgs via this process in a large parameter space.

Charged higgs production at photon colliders in 2HDM-III

We study charged Higgs production in the process $\gamma\gamma\to A^0\to W^- H^+$. The processes $\gamma\gamma\to A^0$ are loop mediated in a 2HDM. This is due to the fact that photons only couple directly to charged particles and the Higgs only couples to particles with mass acquired via Higgs mechanism. Although in MSSM the contribution from the process $\gamma\gamma\to A^0$ is too small, it has been found that in a more general 2HDM it could be enhanced. On the other hand, the boson $A^0$ can decay in $W^- H^+$ at tree level and the charged Higgs can decay in fermions. So, the whole process under study is $\gamma\gamma\to A^0\to (W^-\to l\nu) (H^+\to f_if_j)$ in 2HDM-III. Evidence about charged Higgs existence could demonstrate that structure of the Higgs sector has several multiplets.

Detection of two-photon exclusive production of supersymmetric pairs at the LHC

The detection of pairs of sleptons, charginos and charged higgs bosons produced via photon-photon fusion at the LHC is studied, assuming a couple of benchmark points of the MSSM model. Due to low cross sections, it requires large integrated luminosity, but thanks to the striking signature of these exclusive processes the backgrounds are low, and are well known. Very forward proton detectors can be used to measure the photon energies, allowing for direct determination of masses of the lightest SUSY particle, of selectrons and smuons with a few GeV resolution. Finally, the detection and mass measurement of quasi-stable particles predicted by the so-called sweet spot supersymmetry is discussed. Comment: 9 pages, 5 tables, 8 figures. Talk given at the Workshop on High-energy photon collisions at the LHC, April 22-25, 2008, CERN, Switzerland. To appear in the proceedings

New particle searches with τ at DELPHI

The τ lepton has played an important role in many new physics searches performed at the DELPHI experiment at LEP. In this paper the basic selection and identification techniques are outlined. Some of the most interesting searches are described: charged higgs, doubly charged higgs, sleptons or excited leptons.

Direct search for charged higgs bosons in decays of top quarks.

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Search for charged higgs bosons in e+e− collisions at DELPHI

A search for pair produced charged Higgs bosons was performed using the data collected by the DELPHI detector at LEP II at centre-of-mass energies up to 208 GeV. The three different final states, τντν, c s τν and c s c s were considered. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 75.0 GeV/ c 2 has been excluded at 95% confidence level.

The Voloshin-Vysotski-Okun solution to the solar-neutrino problem in a left-right model

The apparent anticorrelation between the solarneutrino flux and the sun-spot number can be explained if electron neutrino has a large magnetic moment. A model with SU(2) L ×SU(2) R ×U(1) B−l gauge interaction is presented in which the electron neutrino has a large magnetic moment. The ingredients of the model are (i) the absence of the usual discrete left-right symmetry, (ii) new fermions that are singlets under SU(2) L and SU(2) R and (iii) two doublets and a charged singlet of higgs. The model utilises the see-saw mechanism of Gell-Mann, Ramond and Slansky give masses to all quarks and leptons. The large magnetic moment of the electron neutrino is achieved through charged singlet higgs fields.

Charged higgs contributions to rare weak processes in a supergravity model

Charged Higgs contributions to\(Z^0 \to b\bar s + \bar bs\) andb→sγ are examined in a no-scaleN=1 suppergravity model taking into account the constraints typical of the model. Even with these rather restrictive constraints, such contributions can very well dominate over the gluino-induced effects.

New limits on charged higgs boson mass with cello at petra and status of the neutral Higgs boson search

A search has been performed for charged Higgs bosons in e +e − annihilation at center of mass energies up to 46.8 GeV. From absence of both hadronic and leptonic signatures, we exclude them up to a mass of 19 GeV/c 2, independently of the hadronic and leptonic branching ratios. The situation of the neutral Higgs search is briefly reviewed. Presently, only some ranges in its mass spectrum are excluded, so that its search is interesting both at low and high energy.

An upper limit on the masses of the charged higgs bosons in the Gelmini-Roncadelli model

The Gelmini-Roncadelli model allows neutrino masses via an enlarged Higgs sector. One-loop corrections to W ± and Z masses from the Higgs potential of this model are calculated, to leading order in heavy Higgs masses. Using the value of the ϱ parameter, the masses of the charged scalars are bounded.

Production of charged and neutral higgs bosons in high energy lepton-nucleon interactions

We give a detailed calculation for the production of charged and neutral Higgs bosons in lepton-nucleon collisions in the framework of simple extended Weinberg-Salam models. The production cross section in the doublet-doublet models is in general much larger than that in the doublet-triplet models. In the doublet-doublet models the production cross section of neutral Higgs bosons through bremstralung off heavy quarks may be by an order of magnitude larger than that of the neutral Higgs boson in the Weinberg-Salam model, and by several times smaller than that of the charged Higgs boson in the doublet-doublet models. In the HERAep collider withs∼105 GeV2, there may be 1 event per 2 to 7 days for the production of a charged Higgs boson withm H ≲20 GeV.

Bounds on charged higgs properties from CP violation

We examine bounds from CP violation in the neutral K system on charged Higgs masses and couplings in models with two Higgs doublets. While CP violation is still due only to a non-zero phase in the Kobayashi-Maskawa matrix, there are additional short-distance contributions involving charged Higgs exchange rather than W exchange. By having CP violation in the mass matrix, but not in K → ππ decay amplitude, largely due to Higgs exchange, it is possible to obtain a small value of ϵ′/ ϵ.

Charged hyperpions, charged higgs bosons and the leptonic decays of the heavy open-top mesonsT b * andT b

We study the leptonic decay modes of the vectorTb* and pseudoscalarTb t-flavored mesons in the framework of some extended technicolor models and for the standardSU(2)×U(1) model with two complex Higgs doublets. We find that the ratioГ(Tb* →l vГ(T →l v) bcan help in discriminating among these models but, unfortunately, the experimental prospects for detecting these decay modes are not very bright.

Search for charged higgs and technipions at petra

We have searched for hadronic decay modes of unstable pointlike charged spin-zero particles such as charged Higgs bosons or technipions, produced in pairs in e +e − annihilation. Together with previous results on leptonic decay modes from other experiments, we conclude that at the 95% confidence level such particles do not exist in the mass range of 5 to 13 GeV.