Search for High Transverse Momentum Lepton Pairs in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV

A new signature-based search has been devised, sensitive to an excess of opposite-sign electron or muon pairs at high dilepton transverse momentum~($q_T$) and moderate di-lepton mass~($M_{\ell\ell}$). Such pairs would be expected in the associated production of~$\tilde{\chi}^+_1\tilde{\chi}^0_2$, for example. The technique is completely new, with several advantages over the classical `tri-lepton' search, which it complements. The key component is the comparison of events in a given range of~$M_{\ell\ell}$ to those in the region of the $Z$-resonance, as a function of~$q_T$. We have obtained a preliminary result in the di-muon channel, based on approximately $325$ pb$^{-1}$ of~$p\bar{p}$ collisions recorded with the CDF~II detector.