Inclusive Search for New Physics with Like-Sign Dilepton Events in $p\overline{p}$ Collisions at $\sqrt{s}=1.96\mathrm{TeV}$

We describe a search for anomalous production of events with two leptons ($e$ or $\mu$) of the same electric charge in $p\overline{p}$ collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two leptons of the same electric charge. This search has a significant increase in sensitivity compared to earlier searches. Using a data sample corresponding to $1{\mathrm{fb}}^{-1}$ of integrated luminosity recorded by the CDF II detector, we observe no significant excess in an inclusive selection (expect $33.2\pm 4.7$ events, observe 44) or in a supersymmetry-optimized selection (expect $7.8\pm 1.1$ events, observe 13.)

Figure 1

Invariant mass distribution $m_{\ell \ell }$ of the selected leptons (a), ${\mathrm{E̸}}_T$ (b), leading (c), and subleading (d) lepton transverse momentum in data and simulation. The rightmost bins are overflow bins. The peak at $m_{\ell \ell }\approx 90\mathrm{GeV}$ is mostly due to Drell-Yan di-electron production with hard radiation off one electron, followed by an asymmetric conversion.