CDF CHAMPs Search

Under some circumstances, new massive particles arising from physics beyond the Standard Model will have lifetimes that are long compared to the transit time through the detector. In these cases, direct searches for decay products will fail, and the limits obtained will not hold. If such a particle is charged, it will appear in the detector as a slowly moving, highly ionizing and highly penentrating particle with large transverse momentum that will typically be reconstructed as a muon. We present the results of a model-independent search for charged massive stable particles by measuring the time-of-flight of high transverse momentum tracks in events collected using a high transverse momentum muon trigger. Our results, based upon 1.03 fb-1 of pbar-p collisions at sqrt{s} = 1.9 TeV, are consistent with background. We set a model independent limit on the production cross section of a single fiducial strongly interacting CHAMP of 48 fb at 95% C.L., and 10 fb for a single fiducial weakly interacting CHAMP. Within the context of a general model of stable stop pair production, we set a lower stop mass limit of 250 GeV/c2 at 95% C.L.

## Plots and Tables:

 Momentum_Sig_Ctl_Lin Momentum for the control region and signal region in the $W\to e\nu$ dataset. eps pdf gif TOF_beta_Sig_Ctl_Lin TOF beta for the control region and signal region in the $W\to e\nu$ dataset. eps pdf gif TOFmass_Sig_Ctl_Linear TOF mass for the control region and signal region in the $W\to e\nu$ dataset. eps pdf gif t0DiffCut TOF $t_0$ $-$ COT $t_0$ in the $W\to e\nu$ dataset. eps pdf gif TOFmass_Ctl_pred_cut_Wenu Control-region mass (after cleanup cuts) calculated from $\beta_{\rm TOF}$ and the track momentum for the $W\to e\nu$ dataset. The histogram is for all control-region events, while the red line is the prediction. eps pdf gif TOFmass_Signal_pred_cut_Wenu0 Signal-region mass calculated from $\beta_{\rm TOF}$ and the track momentum for the $W\to e\nu$ dataset. The histogram is for events after cleanup cuts, while the red line is the prediction using the control-region $\beta$. eps pdf gif TOFmass_Signal_pred_Int_cut_Wenu Signal-region mass calculated from $\beta_{\rm TOF}$ and the track momentum for the $W\to e\nu$ dataset. The histogram is for events after cleanup cuts, while the red line is the prediction using the control-region $\beta$. eps pdf gif Momentum_Sig_Ctl_Lin_CMUP Momentum for the control region and signal region in the central muon dataset. eps pdf gif TOF_beta_Sig_Ctl_cut_Lin_CMUP TOF beta for the control region and signal region in the central muon dataset. eps pdf gif TOFmass_pred_cut_CMUP Mass calculated from $\beta_{\rm TOF}$ and the track momentum for the central muon dataset. The histogram is for events after cleanup cuts, while the red line is the prediction using the $20 < p_T < 40$ GeV control-region $\beta$. eps pdf gif TOFmass_pred_cut_CMUP_Stop Mass calculated from $\beta_{\rm TOF}$ and the track momentum for the central muon dataset. The histogram is for events after cleanup cuts, while the red line is the prediction using the $20 < p_T < 40$ GeV control-region $\beta$. The blue line shows the additional events expected for a 220 GeV/$/c^{2}$, and the magenta line shows the addtional events expected for a 220 GeV/$/c^{2}$ stop.} eps pdf gif TOFmass_pred_Int_cut_CMUP Mass calculated from $\beta_{\rm TOF}$ and the track momentum for the central muon dataset. The histogram is for events after cleanup cuts, while the red line is the prediction using the $20 < p_T < 40$ GeV control-region $\beta$. eps pdf gif ExpectedStop Stop expected signal as a function of stop mass. eps pdf gif expectedLimit The theoretical NLO cross section for stop production, calculated using the Prospino program, is plotted as a function of stop mass (red), along with the limits expected for this analysis. eps pdf gif StopXSecLimitCMUP The theoretical NLO cross section for stop production, calculated using the Prospino program~\cite{prospino}, is plotted as a function of stop mass (red), along with the cross section limit for the observed CMUP result. eps pdf gif

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