Tuesday, September 18, 2012

1209.3636 (Sukanta Dutta et al.)

Top quark physics in Vector Color-Octet Model    [PDF]

Sukanta Dutta, Ashok Goyal, Mukesh Kumar
We study and constrain the parameter space of the color octet vector model from the observed data at TeVatron by studying the top quark pair production and associated observables \afbt and spin-correlation. In particular we study the invariant mass and rapidity dependence of \afbt at TeVatron. In addition to the flavor conserving (FC) couplings we extend our study to include the flavor violating (FV) coupling involving the first and third generation quarks for both these processes. We also explore the contribution of this model to the single top quark production mediated by charged and neutral color vector bosons. FV couplings introduced then induce the same sign top pair production process which is analyzed for TeVatron. Our study includes the impact of the decay width of color octets on these cross-sections. We find that it is possible to explain the observed \afbt anomaly in the color octet vector model without transgressing the production cross-sections of all these processes both through FC and FV couplings. We also predict the best point-sets in the model parameter space for specific choices of color octet masses corresponding to $\chi^2_{\rm min}$ evaluated using the \mttb ~ and \dyy spectrum of \afbt from the observed data set of Run II of TeVatron at the integrated luminosity 8.7 fb$^{-1}$. We find that the single top quark production is more sensitive to the FC and FV couplings in comparison to the top-pair production. We provide 95% exclusion contours on the plane of FV chiral couplings from the recent data at TeVatron, CMS and ATLAS corresponding to the non-observability of large same sign di-lepton events.
View original: http://arxiv.org/abs/1209.3636

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