Measurement of the top production cross section rate from gluon-gluon fusion at CDF

We present a measurement of the ratio of top-antitop production cross section via gluon-fusion to the total production cross section in proton-antiproton collisions with $\sqrt(s)$ = 1.96 TeV at the Fermilab Tevatron. The data sample, recorded by CDF II, has an integrated luminosity of 955 pb$^{-1}$. Using an artificial neural network trained on the kinematics to discriminate the gluon-fusion events, we find the ratio of the gluon-fusion cross section to the total cross section to be $<0.33$ at the 68$\%$ confidence level and $< 0.61$ at the 95$\%$ confidence level. Additionally, we combine this measurement with a complementary analysis using the charged particle multiplicity in top-antitop evens and find the ratio to be 0.07+0.15-0.07.