Search for like-sign top quark pair production at CDF with 6.1 fb$^{-1}$

# Search for like-sign top quark pair production at CDF with 6.1 fb$^{-1}$

V. Rusu, FNAL
D. Whiteson and R. Porter, UC Irvine
P. Wittich and P. Kittiwisit, Cornell
### Abstract: We search for production of same-sign top quark at CDF in data with 6.1 fb$^{-1}$ of luminosity. The observed data agree with the standard model predictions. We present limits on same-sign top quark pair production at CDF using effective operators.
 (Click each plot for EPS) Distribution of missing transverse energy for observed events with two like-sign lepton and at least two jets (points). Stacked histograms indicate the expected background contributions, see Table~\ref{tab:yieldsjj (Click each plot for EPS) Distribution of $H_T$ for observed events with two like-sign lepton and at least two jets (points). Stacked histograms indicate the expected background contributions, see Table~\ref{tab:yieldsjj (Click each plot for EPS) Distribution of expected and observed data in $H_T$, with expected same-sign topquark pair signal overlaid. (Click each plot for EPS) Limits on same-sign top quark pair production in left-left, left-right, and right-right chirality modes. Left, in terms of cross-sections, compared to theory predictions for $C=1$. Right, expressed as limits on the $C$ coefficients. See Table~\ref{tab:res (Click each plot for EPS) Limits on two of four operator coefficients assuming the rest is zero. These make the conservative assumption that the kinematics of a combination of two modes ($LL$,$LR$,$RR$) can be described by the mode with the smallest efficiency, $LL$. (Click each plot for PDF) Relation between $A_{fb}$ and the coefficient $|C_{RR}|/\Lambda^{2}$ for flavour-violating $Z'$ model