跳至主要内容

Search for Signatures of New Heavy Top Quark of the Fourth Generation at the Hadron Colliders

Read full paper at：
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=50853#.VE3aUlfHRK0

The Fourth Generation and Vector Like Quark (VLQ) models are extensions of the Standard Model of particles physics. These models predict the existence of new heavy quarks like heavy top quark t' with electric charge 2/3 and heavy bottom quark b' with electric charge -1/3. The t' and b' will act the fourth generation quarks. In current work we present a search for a pair production of a fourth generation quark, t' quark and its antiparticle, followed by their decays to Z, W bosons followed by decays to trilepton  plus jets and missing transverse energy in the final state according to the process . We use Monte Carlo simulation techniques Pythia8, MadGraph5 and CalcHEP to simulate this process at both the Large Hadron Collider at CERN (proton-proton collisions) and the Fermilab Tevatron Collider (proton-antiproton collisions). We assume that the t' quark is a narrow state that always decay to a W and Z bosons plus jets. We select 2 electrons + jets+ missing energy final states with one isolated  with high transverse momentum. The three charged leptons plus missing energy in the final state offer the best discovery potential at the hadron colliders for new heavy top quark mass of 500 GeV. We study the possible signals at both the LHC and the Tevatron of new quarks t' coupled to the third generation quarks in the context of fourth generation and vector like quark models under the assumption of a branching ratios  and . Heavy quark pair production gives interesting signals in final states with three charged leptons plus missing energy. Finally, from our analysis the new heavy fourth generation quark t' can be discovered at both the Tevatron and the LHC with mass 500 GeV.
Cite this paper
Bakhet, N. , Khlopov, M. and Hussein, T. (2014) Search for Signatures of New Heavy Top Quark of the Fourth Generation at the Hadron Colliders. Open Journal of Microphysics, 4, 35-45. doi: 10.4236/ojm.2014.44006.

[1] ATLAS Collaboration (2012) Observation of a New Particle in the Search for the Standard Model Higgs Boson with the ATLAS Detector at the LHC. Physics Letters B, 716, 1-29.
http://dx.doi.org/10.1016/j.physletb.2012.08.020
[2] CMS Collaboration (2012) Observation of a New Boson at a Mass of 125 GeV with the CMS Experiment at the LHC. Physics Letters B, 716, 30-61. http://dx.doi.org/10.1016/j.physletb.2012.08.021
[3] Djouadi, A. and Lenz, A. (2012) Sealing the Fate of a Fourth Generation of Fermions. arXiv:1204.1252v2
[4] ATLAS Collaboration (2011) Update of the Combination of Higgs Boson Searches in pp Collisions at Sqrt(s) = 7 TeV with the ATLAS Experiment at the LHC ATLAS-CONF-2011-135, 2011.
[5] CMS Collaboration (2012) Combined Results of Searches for a Higgs Boson in the Context of the Standard Model and beyond Standard Models. CMS PAS HIG-12-008.
[6] Cetin, S.A., et al. (2011) Status of the Fourth Generation—A Brief Summary of B3SM-III Workshop in Four Parts. arXiv: 1112.2907 [hep-ex].
[7] Aguilar-Saavedra, J.A. JHEP 0911 (2009) Identifying top Partners at LHC. 030.
http://dx.doi.org/10.1088/1126-6708/2009/11/030
[8] Abachi, S. et al. (D0 Collaboration) (1995) Observation of the Top Quark. Physical Review Letters, 74, 2632.
http://dx.doi.org/10.1103/PhysRevLett.74.2632
[9] CMS Collaboration (2012) Search for Pair Produced Fourth-Generation Up-Type Quarks in pp Collisions at Sqrt(s) = 7 TeV with a Lepton in the Final State. CERN-PH-EP/2012-244.
[10] CMS Collaboration (2012) Search for Heavy, Top-Like Quark Pair Production in the Dilepton Final State in pp Collisions at Sqrt(s) = 7. Physics Letters B, 716, 103-121.
http://dx.doi.org/10.1016/j.physletb.2012.07.059
[11] D0 Collaboration (2011) Search for a Fourth Generation t’ Quark in ppbar Collisions at Sqrt(s) =1.96 TeV. arXiv: 1104.4522v.1
[12] Kidonakis, N. (2006) Single Top Quark Production at the Fermilab Tevatron: Threshold Resummation and Finite-Order Soft Gluon Corrections. Physical Review D, 74, 114012.
http://dx.doi.org/10.1103/PhysRevD.74.114012
[13] Campbell, J. and Ellis, R.K. (2002) Next-to-Leading Order Corrections to W + 2 Jet and Z + 2 Jet Production at Hadron Colliders. Physical Review D, 65,113007.
http://dx.doi.org/10.1103/PhysRevD.65.113007
[14] Chatrchyan, S., et al. (CMS Collaboration) (2011) Measurement of the Production Cross Section in pp Collisions at 7 TeV in Lepton + Jets Events Using b-Quark Jet Identification. Physical Review D, 84, 092004.
http://dx.doi.org/10.1103/PhysRevD.84.092004
[15] Kidonakis, N. (2009) Single Top Quark Production at the Fermilab Tevatron: Threshold Resummation and Finite-Order Soft Gluon Corrections. arXiv: 0909.0037.
[16] Alwall, J., et al. (2011) MadGraph 5: Going Beyond. Journal of High Energy Physics, 128.
http://dx.doi.org/10.1007/JHEP06(2011)128
[17] Sjostrand, T. (2006) 026 PYTHIA 6.4 Physics and Manual. JHEP 05 026.
[18] Belyaev, A. (2012) CalcHEP 3.4 for Collider Physics within and beyond the Standard Model. arXiv:1207.6082                           eww141027lx
标签：

评论

发表评论

此博客中的热门博文

Does Immigration Promote the Investment of the Monopolistic Firm?

In the present paper, we examine the effect of increasing uncertainty of immigrants’ growth on the optimal timing of investment of a firm that has a monopolistic power over the labor market. It is revealed that when the uncertainty of immigrants’ growth is more than a threshold level, increasing uncertainty of immigrants’ growth accelerates the optimal timing of firms’ investment and enhances the economic growth, even if the uncertainty of immigrants’ growth is formulated by the geometric Brownian motion, which is in sharp contrast to the standard result that an increase in the uncertainty postpones the optimal timing. With an increase in the immigrants over the past ten years, workforces in the host countries have been growing significantly to the extent that the immigrants represent 70% of the increase in the workforce in Europe, and 47% in the United States as OECD indicates. In the present paper, we attempted to investigate the effect of increased uncertainty caused by the growi...
发表评论
阅读全文

Education Policy Implementation: A Mechanism for Enhancing Primary Education Development in Zanzibar

Education is one of the fundamental rights of individuals; therefore, the government of a country needs to develop and strengthen educational policy and quality as well as to ensure that everyone has equal access to basic education. The improvement of access and quality of education in the world is becoming as an essential factor in development, whereas the basic education (primary school), is acknowledged as a foundation of the higher educational development for every country. To fulfill this goal, governments introduce several policies and procedures; however, it requires some reforms and participation from the politician, policymakers, and other stakeholders to re-examine educational policy so that it can lead to multiplication and betterment of the reforms. Educational reforms actually focus on accountability. A positive educational development and reform is very challenging and needs more effort and strategy on how to use and utilize the resources effectively as such it can achie...
发表评论
阅读全文