Prospects of Searches for Neutral, Long-Lived Particles which Decay to Photons using Timing at CDF

Abstract

We present the prospects of searches for neutral, long-lived particles which decay to photons using their time of arrival measured with a newly installed timing system on the electromagnetic calorimeter (EMTiming) of the Collider Detector at Fermilab (CDF). A Monte Carlo simulation shows that EMTiming can provide separation between decay photons from particles with both a long lifetime and a low boost, and prompt photons from Standard Model backgrounds. Using a gauge mediated supersymmetry breaking (GMSB) $\tilde{\chi}_{1}^{0}\to\gamma\tilde{G}$ model we estimate a quasi-model-independent sensitivity using only direct neutralino pair production, and also estimate the expected 95% confidence level exclusion regions for all superpartner production as a function of the neutralino mass and lifetime. We find that a combination of single photon and diphoton analyses should allow the Tevatron in run II to easily extend the exclusion regions from LEP II at high neutralino masses and lifetimes, and cover much, if not all, of the theoretically favored $m_{\tilde{G}}$ < 1 keV/c^2 parameter space for neutralino masses less than 150 GeV/c^2.