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The Produce Of Charged Scalar Particles Predicted By TTM Model At LHeC

Posted on:2014-10-02Degree:MasterType:Thesis
Country:ChinaCandidate:J GuoFull Text:PDF
GTID:2250330425469458Subject:Theoretical Physics
Abstract/Summary:PDF Full Text Request
The mechanism of electroweak symmetry breaking (EWSB) and the origin of fermion masses continue to be outstanding mystery. The Standard Model (SM), is recognized as the best low energy effective theory, but there are a lot of questions which can not be solved. Based on the problems of SM, people have explored actively new physics theory beyond SM and pro-posed some new physical models. Recently, people are interested in topcolor model, topcolor-assisted technicolor (TC2) model, higgsless model, top triangle moose (TTM) model and so on. Topcolor (<tt>) can provide a better mechanism understanding the problem of large mass of top quark, but could be responsible for at least part of EWSB. In the frame work of TC2model, the topcolor, a new QCD-like interaction, makes small contributions to EWSB and gives rise to the main part of the top quark mass. Technicolor (TC) provides the bulk of EWSB. The light fermions get masses from the extended technicolor (ETC).Higgsless models have emerged as a novel way of understanding the mechanism of EWSB without the presence of a scalar particle in the spectrum. Also incorporated in Higgsless model is a heavy Dirac partner for every SM fermion. The presence of these new fermions, in particu-lar, the heavy top and bottom quarks, gives rise to new one-loop contributions to△ρ, where Ap is the ratio of the strengths of the low energy isotriplet neutral and charged current interactions. Precision measurements require△ρ<O(10-3) and this constraint, along with the need to obtain the large top quark mass, pushes the heavy quark mass into the multi2TeV range, too high to be seen at the LHC. Recently, combing higgsless and topcolor mechanisms, a deconstructed Hig-gsless model was proposed, called the top triangle moose (TTM) model. In this model, EWSB results largely from the Higgsless mechanism while the top quark massis mainly generated by the topcolor mechanism. The TTM model alleviates the tension between obtaining the correct top quark mass and keeping△ρ small that exists in many Higgsless models.TTM model has predicted some new scalar particles (top-pions and top-higgs). It is well known that the possible signals of these new scalar particles have been extensively studied in the literature. However, most of works have done in the context of the TC2model. More phe-nomenology analysis about the top-pions and top-Higgs predicted by the TTM model is needed. In our article, we have considered photoproduction of the charged top-pion associated with a top quark in the frameworks of the TTM and TC2models and compare the numerical results with each other. Our numerical results show that, in the frameworks of both the TTM model and the TC2model, the charged top-pions πt±can be abundantly produced via yb collision, as long as they are not too heavy. In the TC2model, the production cross section is only sensitive to the model-dependent parameter mπt, while it is sensitive to the free parameters sin ω and mπt in the TTM model. For sin ω<0.3, the cross section of the process ep'tπ1-+X is larger than that in the TC2model. For example, for sin ω=0.2, Ee=150GeV and200GeV≤mπt≤600GeV, the value of σ1(tπt-) for the process ep'tπt-+X is in the range of7.3~995fb, while its value is in the range of5x10-2~5.8×102fb in most of the parameter space of the TC2model.
Keywords/Search Tags:New physics model, Charged scalar particles, LHeC, Produce section
PDF Full Text Request
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