arXiv subjects

Xuelei Wang

Publications and source records attributed to Xuelei Wang.

33 records · Page 2Linked to original sources

arXiv2006

The correction of the littlest Higgs model to the Higgs production process $e^+e^-\to e^+e^-H$ at the ILC

The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs model, we study the process $e^{+}e^{-}\to e^{+}e^{-}H$ at the ILC and calculate the correction of the littlest Higgs model to the cross section of this process. The results show that, in the favorable parameter spaces preferred by the electroweak precision data, the value of the relative correction is in the range from a few percent to tens percent. In most case, the correction is large enough to reach the measurement precision of the ILC. Therefore, the correction of the littlest Higgs model to the process $e^{+}e^{-}\to e^{+}e^{-}H$ might be detected at the ILC which will give an ideal way to test the model.

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arXiv2006

New gauge boson $B_{H}$ production associated with W boson pair via $γγ$ collision in the littlest Higgs model

The littlest Higgs model is the most economical little Higgs model. The observation of the new gauge bosons predicted by the littlest Higgs model could serve as a robust signature of the model. The ILC, with the high energy and luminosity, can open an ideal window to probe these new gauge bosons, specially, the lightest $B_H$. In the framework of the littlest Higgs model, we study a gauge boson $B_{H}$ production process $γγ\to W^{+}W^{-}B_H$. The study shows that the cross section of the process can vary in a wide range($10^{-1}-10^1$ fb) in most parameter spaces preferred by the electroweak precision data. The high c.m. energy(For example, $\sqrt{s}=1500$ GeV) can obviously enhance the cross section to the level of tens fb. For the favorable parameter spaces, the sufficient typical events could be assumed at the ILC. Therefore, our study about the process $γγ\to W^{+}W^{-}B_H$ could provide a useful theoretical instruction for probing $B_H$ experimentally at ILC. Furthermore, such process would offer a good chance to study the triple and quartic gauge couplings involving $B_H$ and the SM gauge bosons which shed important light on the symmetry breaking features of the littlest Higgs model.

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arXiv2005

$H_{TC}Π^0$ and $Π^+Π^-$ pair productions at the planned $e^ + e^ -$ colliders in the topcolor-assisted technicolor model

The top-pions($Π^{0,\pm}$) and the top-Higgs($H_{TC}$) are the typical particles predicted by the topcolor-assisted technicolor (TC2) model and the observation of these particles can be regarded as the direct evidence of the TC2 model. In this paper, we study two pair production processes of these new particles, i.e., $e^ + e^ - \to H_{TC}Π^0$ and $e^+e^-\to Π^+Π^-$. The results show that the production rates are at the level of serval fb for $e^ + e^ - \to H_{TC}Π^0$ and tens fb for $e^+e^-\to Π^+Π^-$. These processes can produce the adequate distinct multi-jet final states and the SM background can be efficiently reduced. So, with the high luminosity at the planned linear colliders, the top-pions and top-Higgs can be observable via these two pair production processes without double.

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arXiv2005

Study of the single neutral top-pion production process at $γγ$ collider

$γγ\to Π_t^0$ is the major production mechanism of neutral top-pion at the linear colliders. In this paper, we calculate the cross section of the process $γγ\to Π^0_t$ and discuss the potential to observe the neutral top-pion via its various decay modes at the planned ILC. The study show that, among the various neutral top-pion production processes at the linear colliders, the cross section of $γγ\to Π_t^0$ is the largest one which can reach the level of $10^1-10^2$ fb. Due to the existence of the tree-level flavor-changing coupling $Π_t^0 t\bar{c}$, $γγ\to Π_t^0 \to t\bar{c}$ can provide enough number of typical signals to identify the neutral top-pion with the clean SM background. Therefore, the process $γγ\to Π_t^0$ play an important role in searching for the neutral top-pion and test the TC2 model.

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arXiv2005

Studying top quark decay into the polarized W-boson in the TC2 model

We study the decay mode of top quark decaying into Wb in the TC2 model where the top quark is distinguished from other fermions by participating in a strong interaction. We find that the TC2 correction to the decay width $Γ(t \to b W) $ is generally several percent and maximum value can reach 8% for the currently allowed parameters. The magnitude of such correction is comparable with QCD correction and larger than that of minimal supersymmetric model. Such correction might be observable in the future colliders. We also study the TC2 correction to the branching ratio of top quark decay into the polarized W bosons and find the correction is below $ 1 % $. After considering the TC2 correction, we find that our theoretical predictions about the decay branching ratio are also consistent with the experimental data.

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arXiv2004

The study of the charged top-pion decay processes

In the framework of top-color assisted technicolor(TC2) theory, we study the four decay processes of charged top-pion, i.e., $Π^{+}_{t}\to t\bar{b}$, $Π^{+}_{t}\to c\bar{b}$, $Π^{+}_{t}\to W^{+}γ$, $Π^{+}_{t}\to W^{+}Z^{0}$, the decay branching ratio of these modes are calculated. The results show that the main decay channels of charged top-pion are the tree level modes: $Π_t^+ \to t\bar{b}$ and $Π_t^+ \to c\bar{b}$. Light $Π_t^+$ is easier to be detected than heavy one at future coliders. So, the study provides us some useful information to search for charged top-pion.

hep-ph↗

arXiv2004

Detecting the neutral top-pion at $e^{+}e^{-}$ colliders

We investigate some processes of the associated production of a neutral top-pion $Π^{0}_{t}$ with a pair of fermions($e^{+}e^{-}\to f\bar{f}Π^{0}_{t}$) in the context of top-color-assisted technicolor(TC2) theory at future $e^{+}e^{-}$ colliders. The studies show that the largest cross sections of the processes $e^{+}e^{-}\to f'\bar{f'}Π^{0}_{t}(f'=u,d,c,s,μ,τ)$ could only reach the level of 0.01fb, we can hardly detect a neutral top-pion through these processes. For the processes $e^{+}e^{-}\to e^{+}e^{-}Π^{0}_{t}$, $e^{+}e^{-}\to t\bar{t}Π^{0}_{t}$ and $e^{+}e^{-}\to b\bar{b}Π^{0}_{t}$, the cross sections of these processes are at the level of a few fb for the favorable parameters and a few tens, even hundreds, of neutral top-pion events can be produced at future $e^{+}e^{-}$ colliders each year through these processes. With the clean background of the flavor-changing $t\bar{c}$ channel, the top-pion events can possibly be detected at the planned high luminosity $e^{+}e^{-}$ colliders. Therefore, such neutral top-pion production processes provide a useful way to detect a neutral top-pion and test the TC2 model directly.

hep-ph↗

arXiv2003

Probing neutral top-pion via a flavor-changing process $γγ\to t\bar{c}Π_{t}^{0}$

In the framework of topcolor-assisted-technicolor model(TC2), we study a flavor-changing neutral top-pion production process $γγ\to t\bar{c}Π_{t}^{0}$. The study shows that there exists a resonance effect which can enhance the cross section up to a few fb even tens fb. For a yearly luminosity 100 $fb^{-1}$ at future linear colliders, there might be hundreds even thousands events to be produced. On the other hand, the background of such flavor-changing process is very clean due to the GIM mechanism in SM . With such sufficient events and clean background, neutral toppion could be detected at future linear colliders with high center of energy and luminosity. Our study provides a possible way to test TC2 model.

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arXiv2003

The rare top quark decays $t\to cV$ in the topcolor-assisted technicolor model

We consider the rare top quark decays in the framework of topcolor-assisted technicolor (TC2) model. We find that the contributions of top-pions and top-Higgs predicted by the TC2 model can enhance the SM branching ratios by as much as 6-9 orders of magnitude. i.e., in the most case, the orders of magnitude of branching ratios are $Br(t\to c g)\sim 10^{-5}$, $Br(t\to c Z)\sim 10^{-5}$, $Br(t\to c γ)\sim 10^{-7}$. With the reasonable values of the parameters in TC2 model, such rare top quark decays may be testable in the future experiments. So, rare top quark decays provide us a unique way to test TC2 model.

hep-ph↗

arXiv2002

Associated production of neutral toppion with a pair of heavy quarks in $γγ$ collisions

We have studied a neutral toppion production process $γγ\to f\bar{f}Π_{t}^{0}(f=t,b)$ in the topcolor-assisted technicolor(TC2) model. We find that the cross section of $γγ\to t\bar{t}Π_{t}^{0}$ is much larger than that of $γγ\to b\bar{b}Π_{t}^{0}$. On the other hand, the cross section can be obviously enhanced with the increasing of c.m.energy. With $\sqrt{s}=1600$ GeV, the cross section of $t\bar{t}Π_t^0$ production can reach the level of a few fb. The results show that $γγ\to t\bar{t}Π^0_t \to t\bar{t}(t\bar{c})$ is the most ideal channel to detect neutral toppion due to the clean SM background. With such sufficient signals and clean background, neutral toppion could be detected at TESLA with high c.m.energy.

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arXiv2002

Production of the neutral toppion at the e gamma colliders

In the framework of topcolor-assisted technicolor(TC2) model, we study a neutral toppion production process $e^{-}γ\to e^{-}Π^{0}_{t}$ in this paper. Our results show that the production cross section of $e^{-}γ\to e^{-}Π^{0}_{t}$ can reach the level of several tens fb, and over $10^{3}$ neutral toppion events can be produced in the planned $e^+e^-$ linear colliders each year. Therefore, such a toppion production process provides us a unique chance to detect toppion events and test the TC2 model. On the other hand, the cross section of $e^{-}γ\to e^{-}Π^{0}_{t}$ is about one order of magnitude larger than those of some similar processes in SM and MSSM(i.e., $e^{-}γ\to e^{-}H$ in SM and $e^{-}γ\to e^{-}H^{0}(A^0,h^0)$ in MSSM). So, we can easily distinguish the neutral toppion from other neutral Higgs bosons in SM and MSSM.

hep-ph↗

arXiv2002

The study of a flavor-changing neutral toppion production process $e^+e^-\to t\bar{c}Π_t^0$

We have studied a flavor-changing toppion production process $e^{+}e^{-}\to t\bar{c}Π^{0}_{t}$ in the topcolor-assisted technicolor(TC2) model. The studies show that, with high centre of mass energy in TESLA collider, the production cross section of $e^{+}e^{-}\to t\bar{c}Π^{0}_{t}$ is at the order of magnitude 0.1 fb in most parameter regions of TC2 model and a few tens events of toppion can be produced each year. The resonance effect can enhance the cross section to a few fb when toppion mass is small. With clean background, the toppion events can possibly be detected at TESLA collider. On the other hand, we find that there exists a narrow peak near $m_t-m_c$ in the toppion-charm invariant mass distribution which could be clearly detected. Therefore, such a toppion production process $e^{+}e^{-}\to t\bar{c}Π^{0}_{t}$ provides a unique chance to detect toppion events and test the TC2 model.

hep-ph↗

arXiv2001

Signatures of the neutral top-pion in $eγ$ collisions

We calculate the contributions of the neutral top-pion $π_{t}^0$ to the process $e^-γ\to e^-\bar{t}c$ in the framework of topcolor-assisted technicolor(TC2) models and discuss the possible of detecting $π_t^0$ at the high energy linear $e^+e^-$ collider(LC). Our results show that $π_t^0$ can give significant contributions to this process. With reasonable values of the parameters in TC2 models, the cross section $σ$ can reach 0.19 fb which may be detected at the $eγ$ collisions based on the future LC experiments.

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arXiv1996

Precision Data and Implications on the Parameters of TC theory

Assuming that the actual values of $m_t$ and the data set ($Γ_b$, $Γ_h$, $Γ_Z$, $R_b$, $R_c$, $R_l$) are within their $1-σ$ errors as reported by CDF, D0 and by LEP Collaborations, the parameter $Δ^{new}_b$ which measures the nonoblique corrections on the $Zb\overline{b}$ vertex from new physics can be determined experimentally. According to the precision data one can obtain updated constraints on the parameters $ξ$ and the masses of the charged PGBs.

hep-ph↗

arXiv1995

Pseudo-Goldstone Bosons in Technicolor Models and the Phenomenology

In this report we present a review of recent developments in the TC/ETC theories, concentrating on the theoretical estimations and the phenomenological analysis about the Non-Oblique corrections on the $Zb\overline{b}$ vertex from ETC dynamics and Pseudo-Goldstone Bosons. The relevant studies about the vertex corrections on other processes from the PGBs were also considered.

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