arXiv subjects

Xue-Lei Wang

Publications and source records attributed to Xue-Lei Wang.

14 recordsLinked to original sources

arXiv2010

Pair production of Higgs bosons associated with $Z$ boson in the left-right twin Higgs model at the ILC

The left-right twin Higgs(LRTH) model predicts the existence of three additional Higgs bosons: one neutral Higgs $ϕ^{0}$ and a pair of charged Higgs bosons $ϕ^{\pm}$. In this paper, we studied the production of a pair of charged and neutral Higgs bosons associated with standard model gauge boson $Z$ at the ILC, i.e., $e^{+}e^{-}\rightarrow Zϕ^{+}ϕ^{-}$ and $e^{+}e^{-}\rightarrow Zϕ^{0}ϕ^{0}$. We calculate the production rate and present the distributions of the various observables, such as, the distributions of the energy and the transverse momenta of final $Z$-boson and charged Higgs boson $ϕ^{-}$, the differential cross section of the invariant mass of charged Higgs bosons pair, the distribution of the angle between charged Higgs bosons pair and the production angle distributions of $Z$-boson and charged Higgs boson $ϕ^{-}$. Our numerical results show that, for the process $e^{+}e^{-}\rightarrow Zϕ^{+}ϕ^{-}$, the production rates are at the level of $10^{-1} fb$ with reasonable parameter values. For the process of $e^{+}e^{-}\rightarrow Zϕ^{0}ϕ^{0}$, we find that the production cross section are smaller than $6\times 10^{-3} fb$ in most of parameter space. However, the resonance production cross section can be significantly enhanced.

hep-ph↗

arXiv2010

Higgs boson decays and production in the left-right twin Higgs model

The left-right twin Higgs model predicts one neutral Higgs boson $ϕ_{0}$ and it acquires mass $m_{ϕ_{0}}\sim μ_{r}$ with the $μ$ term, which can be lighter than half the SM-like Higgs boson mass in a portion of parameter space. Thus, the SM-like Higgs boson $h$ can dominantly decay into a pair of light neutral Higgs bosons especially when $m_{h}$ is below the $WW$ threshold. First, we examine the branching ratios of the SM-like Higgs boson decays and find that the new decay mode $h\rightarrow ϕ_{0}ϕ_{0}$ is dominant for the case of $m_{h}>2m_{ϕ_{0}}$. Then we study the production via gluon fusion followed by the decay into two photons or two weak gauge bosons and found that the production rate can be significantly suppressed for some part of parameter space. Finally, we comparatively study the process $γγ\rightarrow h \rightarrow b\bar{b}$ at ILC in the cases of $m_{h}>2m_{ϕ_{0}}$ and $m_{h}<2m_{ϕ_{0}}$, respectively. We find that these predictions can significantly deviated from the SM predictions, e.g., the gluon-gluon fusion channel, in the cases of $m_{h}>2m_{ϕ_{0}}$ and $m_{h}<2m_{ϕ_{0}}$, can be suppressed by about 80% and 45%, respectively. Therefor, it is possible to probe the left-right twin Higgs model via these Higgs boson production processes at the LHC experiment or in the future ILC experiment.

hep-ph↗

arXiv2009

Top-Higgs boson production via gluon fusion at LHC in the TC2 model

In our work: 0903.2612, we calculate the production rate of single top-Higgs boson in the TC2 model which is a modified version of the original top-technicolor model. The similar process was discussed in arXiv:hep-ph/9905347v2. The TC2 model, as we discussed in the introduction part remedies some shortcomings and loophole of the old version. The top-Higgs in the TC2 model is a mixture of the top-Higgs of the toptechnicolor model and that of the ETC model, thus a parameter $ε$ is introduced to denote the mixture. Moreover, we vary the mass range of the top-Higgs within 300 to 800 GeV while in arXiv:hep-ph/9905347v2, the mass range was taken as 200 to 400 GeV. In the work, our numerical results show that the production rate of single top-Higgs in the TC2 model is very close to that in the toptecnicolor model within the mass range of 200 to 400 GeV. This manifests that change from the original toptechnicolor model to the new TC2 version does not much affect the production rate of the top-Higgs even though the two top-Higgs in the two models are different. Beyond the 400 GeV, even the TC2 model predicts a negligible production rate at LHC. Since the phenomenological change is indeed not obvious, there is not much new to report. Even though the two models are somehow different, we believe that the result is not worth publishing. Therefore we decide to withdraw our manuscript.

hep-ph↗

arXiv2008

The NLO corrections of $H_{TC} Π^0$and $Π^ + Π^ - $ pair production at the ILC in the TC2 model

As well known, if the Higgs boson were not observed at LHC, the technicolor model would be the most favorable candidate responsible for the symmetry breaking. To overcome some defects in the previous model, some extended versions have been proposed. In the TC2 model typical signature is existence of heavy $H_{TC}$ and technipion $Π$. A direct proof of validity of the model is to produce them at accelerator. Thus we study the production rates of $ e^ + e^ - \to H_{TC} Π^0 $ and $e^ + e^ - \to Π^ + Π^ -$ at ILC in the topcolor-assisted technicolor (TC2) model. In fact, there is a flood of models belonging to new physics which can result in products with characteristics similar to $H_{TC}+Π$ of the TC2 model. Therefore to distinguish this model from others one may need to investigate some details by calculating the cross section to NLO. We indeed find that the NLO corrections are significant, namely the ratio $δ\equiv (σ_{NLO} - σ_{LO})/σ_{LO} $ in $ e^ + e^ - \to H_{TC} Π^0 $ exceeds 100% within a plausible parameter space.

hep-ph↗

arXiv2007

Pair production of charged Higgs bosons in the Left-Right Twin Higgs model at the ILC and LHC

Left-Right twin Higgs(LRTH) model predicts the existence of a pair of charged Higgs $ϕ^{\pm}$. In this paper, we study the production of the charged Higgs bosons pair $ϕ^{\pm}$ via the process $e^{+}e^{-}\to ϕ^{+}ϕ^{-}$ at the International Linear Collider(ILC). The numerical results show that the production rates are at the level of several tens fb, this process can produce the adequate distinct multi-jet final states and the SM background can be efficiently reduced. We also discuss the charged Higgs boson pair production via the process $q\bar{q}\to ϕ^{+}ϕ^{-}$ at the $CERN$ Large Hadron Collider(LHC) and estimate there production rates. We find that, as long as the charged Higgs bosons are not too heavy, they can be abundantly produced at the LHC. The possible signatures of these new particles might be detected at the ILC and LHC experiments.

hep-ph↗

arXiv2007

Effects of little Higgs models on single top production at the $e^{-}γ$ colliders

In the framework of the littlest Higgs($LH$) model and the littlest Higgs model with T-parity($LHT$), We investigate the single top production process $e^{-}γ\to ν_{e}b\bar{t}$, and calculate the corrections of these two models to the cross section of this process. We find that in the reasonable parameter space, the correction terms for the tree-level $Wtb$ couplings coming from the $LHT$ model can generate significantly corrections to the cross section of this process, which might be detected in the future high energy linear $e^{+}e^{-}$ collider($ILC$) experiments. However, the contributions of the new gauge boson $W^{\pm}_{H}$ predicted by the $LH$ model to this process is very small.

hep-ph↗

arXiv2007

Higgs boson pair production process $e^+e^-\to ZHH$ in the littlest Higgs model at the ILC

The physics prospect at future linear $e^{+}e^{-}$ colliders for the study of the Higgs triple self-coupling via the process of $e^{+}e^{-}\to ZHH$ is investigated. In this paper, we calculate the contribution of the new particles predicted by the littlest Higgs model to the cross sections of this process in the future high energy $e^{+}e^{-}$ collider($ILC$). The results show that, in the favorable parameter spaces preferred by the electroweak precision, the deviation of the total cross sections from its $SM$ value varies from a few percent to tens percent, which may be detected at the future $ILC$ experiments with $\sqrt{s}$=500GeV.

hep-ph↗

arXiv2006

Single production of the vector-like top quark in the littlest Higgs model at TeV energy $e^{-}γ$ colliders

The new colored vector-like heavy fermion $T$ is a crucial prediction in little Higgs models, which plays a key role in breaking the electroweak symmetry. The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs model, we study single production of the new heavy vector-like quark via $e^{-}γ$ collisions and discuss the possibility of detecting this new particle in the TeV energy $e^{+}e^{-}$ collider(LC). We find that the production cross section can vary in a wide range($10^{-3}-10^{1}fb$) in most parameter spaces. For the favorable parameter spaces, the possible signals of the vector-like top quark $T$ can be detected via $e^{-}γ$ collisions in future $LC$ experiment with $\sqrt{s}=3TeV$ and $£=500fb^{-1}$.

hep-ph↗

arXiv2006

The correction of the littlest Higgs model to the Higgs production process $e^{-}γ\to ν_{e}W^{-}H$ in $e^{-}γ$ collisions

The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs(LH) model, we study the process $e^{-}γ\to ν_{e}W^{-}H$ and calculate the contributions of the LH model to the cross section of this process. The results show that, in most of parameter spaces preferred by the electroweak precision data, the value of the relative correction is larger than 10%. Such correction to the process $e^{-}γ\to ν_{e}W^{-}H$ is large enough to be detected via $e^{-}γ$ collisions in the future high energy linear $e^{+}e^{-}$ collider($LC$) experiment with the c.m energy $\sqrt{s}$=500 GeV and a yearly integrated luminosity $£=100fb^{-1}$, which will give an ideal way to test the model.

hep-ph↗

arXiv2000

Reexamination of the Constraint on Topcolor-Assisted Technicolor Models from R_b

Recent study on the charged top-pion correction to R_b shows that it is negative and large, so that the precision experimental value of R_b gives rise to a severe constraint on the topcolor-assisted technicolor models such that the top-pion mass should be of the order of 1 TeV. In this paper, we restudy this constraint by further taking account the extended technicolor gauge boson correction which is positive. With this positive contribution to R_b, the constraint on the topcolor-assisted technicolor models from R_b changes significantly. The top-pion mass is allowed to be in the region of a few hundred GeV depending on the models.

hep-ph↗

arXiv2000

Pseudo-Goldstone Boson Effects in Top-Antitop Productions at High Energy Hadron Colliders and Testing Technicolor Models

We study the top quark pair production process p+p(anti-p)-->top+antitop in various kinds of technicolor (TC) models at the Fermilab Tevatron Run II and the CERN LHC. The s-channel neutral pseudo-Goldstone bosons (PGB's) contribute dominately to the production amplitudes from its coupling to the gluons through the triangle loops of techniquarks and the top quark. Cross sections in different TC models with s-channel PGB contributions are calculated. It is shown that the PGB effects can be experimentally tested and different TC models under consideration can be distinguished at the LHC. Therefore, the p+p-->top+antitop process at the LHC provides feasible tests of the TC models.

hep-ph↗

arXiv1999

Derivation of the Effective Chiral Lagrangian for Pseudoscalar Mesons from QCD

We formally derive the chiral Lagrangian for low lying pseudoscalar mesons from the first principles of QCD considering the contributions from the normal part of the theory without taking approximations. The derivation is based on the standard generating functional of QCD in the path integral formalism. The gluon-field integration is formally carried out by expressing the result in terms of physical Green's functions of the gluon. To integrate over the quark-field, we introduce a bilocal auxiliary field Phi(x,y) representing the mesons. We then develop a consistent way of extracting the local pseudoscalar degree of freedom U(x) in Phi(x,y) and integrating out the rest degrees of freedom such that the complete pseudoscalar degree of freedom resides in U(x). With certain techniques, we work out the explicit U(x)-dependence of the effective action up to the p^4-terms in the momentum expansion, which leads to the desired chiral Lagrangian in which all the coefficients contributed from the normal part of the theory are expressed in terms of certain Green's functions in QCD. Together with the existing QCD formulae for the anomaly contributions, the present results leads to the complete QCD definition of the coefficients in the chiral Lagrangian. The relation between the present QCD definition of the p^2-order coefficient F_0^2 and the well-known approximate result given by Pagels and Stokar is discussed.

hep-ph↗

arXiv1999

Derivation of the Gasser-Leutwyler Lagrangian from QCD

The normal part of the Gasser-Leutwyler formulation of the chiral Lagrangian is formally derived from the first principles of QCD without taking approximations. All the coefficients are expressed in terms of certain Green's functions in QCD, which can be regarded as the general QCD definitions of the normal part of the coefficients. The approximate values of the coefficients are also presented.

hep-ph↗

arXiv1999

Single top Quark Production in e-gamma Collisions and Testing Technicolor Models

We study the single top quark production process in various kinds of technicolor models in high energy positron photon collisions at the future electron positron linear colliders. It is shown that if there is certain charged pseudo Goldstone boson (PGB) coupling to t(anti-b), the t(anti-b)-channel PGB contribution is dominant, but the situation is quite different from that in the neutral channel, t(anti-t) production in photon photon collisions, due to the destructive nature of different amplitudes. At the DESY limear collider TESLA, the event rates in models with t(anti-b)-channel PGB contributions, such as the top-color-assisted technicolor model, etc. are experimentally measurable. This process provides a feasible test of technicolor models with t(abti-b)-channel PGB contributions.

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